1 | =head1 NAME
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2 |
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3 | perl561delta - what's new for perl v5.6.x
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4 |
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5 | =head1 DESCRIPTION
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6 |
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7 | This document describes differences between the 5.005 release and the 5.6.1
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8 | release.
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9 |
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10 | =head1 Summary of changes between 5.6.0 and 5.6.1
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11 |
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12 | This section contains a summary of the changes between the 5.6.0 release
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13 | and the 5.6.1 release. More details about the changes mentioned here
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14 | may be found in the F<Changes> files that accompany the Perl source
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15 | distribution. See L<perlhack> for pointers to online resources where you
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16 | can inspect the individual patches described by these changes.
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17 |
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18 | =head2 Security Issues
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19 |
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20 | suidperl will not run /bin/mail anymore, because some platforms have
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21 | a /bin/mail that is vulnerable to buffer overflow attacks.
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22 |
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23 | Note that suidperl is neither built nor installed by default in
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24 | any recent version of perl. Use of suidperl is highly discouraged.
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25 | If you think you need it, try alternatives such as sudo first.
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26 | See http://www.courtesan.com/sudo/ .
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27 |
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28 | =head2 Core bug fixes
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29 |
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30 | This is not an exhaustive list. It is intended to cover only the
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31 | significant user-visible changes.
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32 |
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33 | =over
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34 |
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35 | =item C<UNIVERSAL::isa()>
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36 |
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37 | A bug in the caching mechanism used by C<UNIVERSAL::isa()> that affected
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38 | base.pm has been fixed. The bug has existed since the 5.005 releases,
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39 | but wasn't tickled by base.pm in those releases.
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40 |
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41 | =item Memory leaks
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42 |
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43 | Various cases of memory leaks and attempts to access uninitialized memory
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44 | have been cured. See L</"Known Problems"> below for further issues.
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45 |
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46 | =item Numeric conversions
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47 |
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48 | Numeric conversions did not recognize changes in the string value
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49 | properly in certain circumstances.
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50 |
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51 | In other situations, large unsigned numbers (those above 2**31) could
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52 | sometimes lose their unsignedness, causing bogus results in arithmetic
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53 | operations.
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54 |
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55 | Integer modulus on large unsigned integers sometimes returned
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56 | incorrect values.
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57 |
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58 | Perl 5.6.0 generated "not a number" warnings on certain conversions where
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59 | previous versions didn't.
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60 |
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61 | These problems have all been rectified.
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62 |
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63 | Infinity is now recognized as a number.
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64 |
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65 | =item qw(a\\b)
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66 |
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67 | In Perl 5.6.0, qw(a\\b) produced a string with two backslashes instead
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68 | of one, in a departure from the behavior in previous versions. The
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69 | older behavior has been reinstated.
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70 |
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71 | =item caller()
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72 |
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73 | caller() could cause core dumps in certain situations. Carp was sometimes
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74 | affected by this problem.
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75 |
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76 | =item Bugs in regular expressions
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77 |
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78 | Pattern matches on overloaded values are now handled correctly.
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79 |
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80 | Perl 5.6.0 parsed m/\x{ab}/ incorrectly, leading to spurious warnings.
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81 | This has been corrected.
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82 |
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83 | The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
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84 | of simple pattern matches. These are now handled better.
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85 |
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86 | Regular expression debug output (whether through C<use re 'debug'>
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87 | or via C<-Dr>) now looks better.
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88 |
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89 | Multi-line matches like C<"a\nxb\n" =~ /(?!\A)x/m> were flawed. The
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90 | bug has been fixed.
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91 |
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92 | Use of $& could trigger a core dump under some situations. This
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93 | is now avoided.
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94 |
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95 | Match variables $1 et al., weren't being unset when a pattern match
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96 | was backtracking, and the anomaly showed up inside C</...(?{ ... }).../>
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97 | etc. These variables are now tracked correctly.
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98 |
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99 | pos() did not return the correct value within s///ge in earlier
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100 | versions. This is now handled correctly.
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101 |
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102 | =item "slurp" mode
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103 |
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104 | readline() on files opened in "slurp" mode could return an extra "" at
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105 | the end in certain situations. This has been corrected.
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106 |
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107 | =item Autovivification of symbolic references to special variables
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108 |
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109 | Autovivification of symbolic references of special variables described
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110 | in L<perlvar> (as in C<${$num}>) was accidentally disabled. This works
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111 | again now.
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112 |
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113 | =item Lexical warnings
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114 |
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115 | Lexical warnings now propagate correctly into C<eval "...">.
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116 |
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117 | C<use warnings qw(FATAL all)> did not work as intended. This has been
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118 | corrected.
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119 |
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120 | Lexical warnings could leak into other scopes in some situations.
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121 | This is now fixed.
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122 |
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123 | warnings::enabled() now reports the state of $^W correctly if the caller
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124 | isn't using lexical warnings.
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125 |
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126 | =item Spurious warnings and errors
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127 |
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128 | Perl 5.6.0 could emit spurious warnings about redefinition of dl_error()
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129 | when statically building extensions into perl. This has been corrected.
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130 |
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131 | "our" variables could result in bogus "Variable will not stay shared"
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132 | warnings. This is now fixed.
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133 |
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134 | "our" variables of the same name declared in two sibling blocks
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135 | resulted in bogus warnings about "redeclaration" of the variables.
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136 | The problem has been corrected.
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137 |
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138 | =item glob()
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139 |
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140 | Compatibility of the builtin glob() with old csh-based glob has been
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141 | improved with the addition of GLOB_ALPHASORT option. See C<File::Glob>.
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142 |
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143 | File::Glob::glob() has been renamed to File::Glob::bsd_glob()
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144 | because the name clashes with the builtin glob(). The older
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145 | name is still available for compatibility, but is deprecated.
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146 |
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147 | Spurious syntax errors generated in certain situations, when glob()
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148 | caused File::Glob to be loaded for the first time, have been fixed.
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149 |
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150 | =item Tainting
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151 |
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152 | Some cases of inconsistent taint propagation (such as within hash
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153 | values) have been fixed.
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154 |
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155 | The tainting behavior of sprintf() has been rationalized. It does
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156 | not taint the result of floating point formats anymore, making the
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157 | behavior consistent with that of string interpolation.
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158 |
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159 | =item sort()
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160 |
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161 | Arguments to sort() weren't being provided the right wantarray() context.
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162 | The comparison block is now run in scalar context, and the arguments to
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163 | be sorted are always provided list context.
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164 |
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165 | sort() is also fully reentrant, in the sense that the sort function
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166 | can itself call sort(). This did not work reliably in previous releases.
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167 |
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168 | =item #line directives
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169 |
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170 | #line directives now work correctly when they appear at the very
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171 | beginning of C<eval "...">.
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172 |
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173 | =item Subroutine prototypes
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174 |
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175 | The (\&) prototype now works properly.
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176 |
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177 | =item map()
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178 |
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179 | map() could get pathologically slow when the result list it generates
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180 | is larger than the source list. The performance has been improved for
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181 | common scenarios.
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182 |
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183 | =item Debugger
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184 |
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185 | Debugger exit code now reflects the script exit code.
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186 |
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187 | Condition C<"0"> in breakpoints is now treated correctly.
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188 |
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189 | The C<d> command now checks the line number.
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190 |
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191 | C<$.> is no longer corrupted by the debugger.
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192 |
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193 | All debugger output now correctly goes to the socket if RemotePort
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194 | is set.
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195 |
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196 | =item PERL5OPT
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197 |
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198 | PERL5OPT can be set to more than one switch group. Previously,
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199 | it used to be limited to one group of options only.
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200 |
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201 | =item chop()
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202 |
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203 | chop(@list) in list context returned the characters chopped in reverse
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204 | order. This has been reversed to be in the right order.
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205 |
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206 | =item Unicode support
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207 |
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208 | Unicode support has seen a large number of incremental improvements,
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209 | but continues to be highly experimental. It is not expected to be
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210 | fully supported in the 5.6.x maintenance releases.
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211 |
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212 | substr(), join(), repeat(), reverse(), quotemeta() and string
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213 | concatenation were all handling Unicode strings incorrectly in
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214 | Perl 5.6.0. This has been corrected.
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215 |
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216 | Support for C<tr///CU> and C<tr///UC> etc., have been removed since
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217 | we realized the interface is broken. For similar functionality,
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218 | see L<perlfunc/pack>.
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219 |
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220 | The Unicode Character Database has been updated to version 3.0.1
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221 | with additions made available to the public as of August 30, 2000.
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222 |
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223 | The Unicode character classes \p{Blank} and \p{SpacePerl} have been
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224 | added. "Blank" is like C isblank(), that is, it contains only
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225 | "horizontal whitespace" (the space character is, the newline isn't),
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226 | and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space}
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227 | isn't, since that includes the vertical tabulator character, whereas
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228 | C<\s> doesn't.)
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229 |
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230 | If you are experimenting with Unicode support in perl, the development
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231 | versions of Perl may have more to offer. In particular, I/O layers
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232 | are now available in the development track, but not in the maintenance
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233 | track, primarily to do backward compatibility issues. Unicode support
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234 | is also evolving rapidly on a daily basis in the development track--the
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235 | maintenance track only reflects the most conservative of these changes.
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236 |
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237 | =item 64-bit support
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238 |
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239 | Support for 64-bit platforms has been improved, but continues to be
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240 | experimental. The level of support varies greatly among platforms.
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241 |
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242 | =item Compiler
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243 |
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244 | The B Compiler and its various backends have had many incremental
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245 | improvements, but they continue to remain highly experimental. Use in
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246 | production environments is discouraged.
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247 |
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248 | The perlcc tool has been rewritten so that the user interface is much
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249 | more like that of a C compiler.
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250 |
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251 | The perlbc tools has been removed. Use C<perlcc -B> instead.
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252 |
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253 | =item Lvalue subroutines
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254 |
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255 | There have been various bugfixes to support lvalue subroutines better.
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256 | However, the feature still remains experimental.
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257 |
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258 | =item IO::Socket
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259 |
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260 | IO::Socket::INET failed to open the specified port if the service
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261 | name was not known. It now correctly uses the supplied port number
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262 | as is.
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263 |
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264 | =item File::Find
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265 |
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266 | File::Find now chdir()s correctly when chasing symbolic links.
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267 |
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268 | =item xsubpp
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269 |
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270 | xsubpp now tolerates embedded POD sections.
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271 |
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272 | =item C<no Module;>
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273 |
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274 | C<no Module;> does not produce an error even if Module does not have an
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275 | unimport() method. This parallels the behavior of C<use> vis-a-vis
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276 | C<import>.
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277 |
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278 | =item Tests
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279 |
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280 | A large number of tests have been added.
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281 |
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282 | =back
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283 |
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284 | =head2 Core features
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285 |
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286 | untie() will now call an UNTIE() hook if it exists. See L<perltie>
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287 | for details.
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288 |
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289 | The C<-DT> command line switch outputs copious tokenizing information.
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290 | See L<perlrun>.
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291 |
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292 | Arrays are now always interpolated in double-quotish strings. Previously,
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293 | C<"[email protected]"> used to be a fatal error at compile time, if an array
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294 | C<@bar> was not used or declared. This transitional behavior was
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295 | intended to help migrate perl4 code, and is deemed to be no longer useful.
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296 | See L</"Arrays now always interpolate into double-quoted strings">.
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297 |
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298 | keys(), each(), pop(), push(), shift(), splice() and unshift()
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299 | can all be overridden now.
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300 |
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301 | C<my __PACKAGE__ $obj> now does the expected thing.
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302 |
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303 | =head2 Configuration issues
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304 |
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305 | On some systems (IRIX and Solaris among them) the system malloc is demonstrably
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306 | better. While the defaults haven't been changed in order to retain binary
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307 | compatibility with earlier releases, you may be better off building perl
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308 | with C<Configure -Uusemymalloc ...> as discussed in the F<INSTALL> file.
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309 |
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310 | C<Configure> has been enhanced in various ways:
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311 |
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312 | =over
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313 |
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314 | =item *
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315 |
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316 | Minimizes use of temporary files.
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317 |
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318 | =item *
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319 |
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320 | By default, does not link perl with libraries not used by it, such as
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321 | the various dbm libraries. SunOS 4.x hints preserve behavior on that
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322 | platform.
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323 |
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324 | =item *
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325 |
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326 | Support for pdp11-style memory models has been removed due to obsolescence.
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327 |
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328 | =item *
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329 |
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330 | Building outside the source tree is supported on systems that have
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331 | symbolic links. This is done by running
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332 |
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333 | sh /path/to/source/Configure -Dmksymlinks ...
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334 | make all test install
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335 |
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336 | in a directory other than the perl source directory. See F<INSTALL>.
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337 |
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338 | =item *
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339 |
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340 | C<Configure -S> can be run non-interactively.
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341 |
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342 | =back
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343 |
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344 | =head2 Documentation
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345 |
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346 | README.aix, README.solaris and README.macos have been added.
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347 | README.posix-bc has been renamed to README.bs2000. These are
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348 | installed as L<perlaix>, L<perlsolaris>, L<perlmacos>, and
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349 | L<perlbs2000> respectively.
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350 |
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351 | The following pod documents are brand new:
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352 |
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353 | perlclib Internal replacements for standard C library functions
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354 | perldebtut Perl debugging tutorial
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355 | perlebcdic Considerations for running Perl on EBCDIC platforms
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356 | perlnewmod Perl modules: preparing a new module for distribution
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357 | perlrequick Perl regular expressions quick start
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358 | perlretut Perl regular expressions tutorial
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359 | perlutil utilities packaged with the Perl distribution
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360 |
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361 | The F<INSTALL> file has been expanded to cover various issues, such as
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362 | 64-bit support.
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363 |
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364 | A longer list of contributors has been added to the source distribution.
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365 | See the file C<AUTHORS>.
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366 |
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367 | Numerous other changes have been made to the included documentation and FAQs.
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368 |
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369 | =head2 Bundled modules
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370 |
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371 | The following modules have been added.
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372 |
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373 | =over
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374 |
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375 | =item B::Concise
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376 |
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377 | Walks Perl syntax tree, printing concise info about ops. See L<B::Concise>.
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378 |
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379 | =item File::Temp
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380 |
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381 | Returns name and handle of a temporary file safely. See L<File::Temp>.
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382 |
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383 | =item Pod::LaTeX
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384 |
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385 | Converts Pod data to formatted LaTeX. See L<Pod::LaTeX>.
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386 |
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387 | =item Pod::Text::Overstrike
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388 |
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389 | Converts POD data to formatted overstrike text. See L<Pod::Text::Overstrike>.
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390 |
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391 | =back
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392 |
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393 | The following modules have been upgraded.
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394 |
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395 | =over
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396 |
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397 | =item CGI
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398 |
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399 | CGI v2.752 is now included.
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400 |
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401 | =item CPAN
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402 |
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403 | CPAN v1.59_54 is now included.
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404 |
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405 | =item Class::Struct
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406 |
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407 | Various bugfixes have been added.
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408 |
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409 | =item DB_File
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410 |
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411 | DB_File v1.75 supports newer Berkeley DB versions, among other
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412 | improvements.
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413 |
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414 | =item Devel::Peek
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415 |
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416 | Devel::Peek has been enhanced to support dumping of memory statistics,
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417 | when perl is built with the included malloc().
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418 |
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419 | =item File::Find
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420 |
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421 | File::Find now supports pre and post-processing of the files in order
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422 | to sort() them, etc.
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423 |
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424 | =item Getopt::Long
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425 |
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426 | Getopt::Long v2.25 is included.
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427 |
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428 | =item IO::Poll
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429 |
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430 | Various bug fixes have been included.
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431 |
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432 | =item IPC::Open3
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433 |
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434 | IPC::Open3 allows use of numeric file descriptors.
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435 |
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436 | =item Math::BigFloat
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437 |
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438 | The fmod() function supports modulus operations. Various bug fixes
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439 | have also been included.
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440 |
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441 | =item Math::Complex
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442 |
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443 | Math::Complex handles inf, NaN etc., better.
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444 |
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445 | =item Net::Ping
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446 |
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447 | ping() could fail on odd number of data bytes, and when the echo service
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448 | isn't running. This has been corrected.
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449 |
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450 | =item Opcode
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451 |
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452 | A memory leak has been fixed.
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453 |
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454 | =item Pod::Parser
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455 |
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456 | Version 1.13 of the Pod::Parser suite is included.
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457 |
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458 | =item Pod::Text
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459 |
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460 | Pod::Text and related modules have been upgraded to the versions
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461 | in podlators suite v2.08.
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462 |
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463 | =item SDBM_File
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464 |
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465 | On dosish platforms, some keys went missing because of lack of support for
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466 | files with "holes". A workaround for the problem has been added.
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467 |
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468 | =item Sys::Syslog
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469 |
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470 | Various bug fixes have been included.
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471 |
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472 | =item Tie::RefHash
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473 |
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474 | Now supports Tie::RefHash::Nestable to automagically tie hashref values.
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475 |
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476 | =item Tie::SubstrHash
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477 |
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478 | Various bug fixes have been included.
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479 |
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480 | =back
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481 |
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482 | =head2 Platform-specific improvements
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483 |
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484 | The following new ports are now available.
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485 |
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486 | =over
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487 |
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488 | =item NCR MP-RAS
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489 |
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490 | =item NonStop-UX
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491 |
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492 | =back
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493 |
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494 | Perl now builds under Amdahl UTS.
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495 |
|
---|
496 | Perl has also been verified to build under Amiga OS.
|
---|
497 |
|
---|
498 | Support for EPOC has been much improved. See README.epoc.
|
---|
499 |
|
---|
500 | Building perl with -Duseithreads or -Duse5005threads now works
|
---|
501 | under HP-UX 10.20 (previously it only worked under 10.30 or later).
|
---|
502 | You will need a thread library package installed. See README.hpux.
|
---|
503 |
|
---|
504 | Long doubles should now work under Linux.
|
---|
505 |
|
---|
506 | Mac OS Classic is now supported in the mainstream source package.
|
---|
507 | See README.macos.
|
---|
508 |
|
---|
509 | Support for MPE/iX has been updated. See README.mpeix.
|
---|
510 |
|
---|
511 | Support for OS/2 has been improved. See C<os2/Changes> and README.os2.
|
---|
512 |
|
---|
513 | Dynamic loading on z/OS (formerly OS/390) has been improved. See
|
---|
514 | README.os390.
|
---|
515 |
|
---|
516 | Support for VMS has seen many incremental improvements, including
|
---|
517 | better support for operators like backticks and system(), and better
|
---|
518 | %ENV handling. See C<README.vms> and L<perlvms>.
|
---|
519 |
|
---|
520 | Support for Stratus VOS has been improved. See C<vos/Changes> and README.vos.
|
---|
521 |
|
---|
522 | Support for Windows has been improved.
|
---|
523 |
|
---|
524 | =over
|
---|
525 |
|
---|
526 | =item *
|
---|
527 |
|
---|
528 | fork() emulation has been improved in various ways, but still continues
|
---|
529 | to be experimental. See L<perlfork> for known bugs and caveats.
|
---|
530 |
|
---|
531 | =item *
|
---|
532 |
|
---|
533 | %SIG has been enabled under USE_ITHREADS, but its use is completely
|
---|
534 | unsupported under all configurations.
|
---|
535 |
|
---|
536 | =item *
|
---|
537 |
|
---|
538 | Borland C++ v5.5 is now a supported compiler that can build Perl.
|
---|
539 | However, the generated binaries continue to be incompatible with those
|
---|
540 | generated by the other supported compilers (GCC and Visual C++).
|
---|
541 |
|
---|
542 | =item *
|
---|
543 |
|
---|
544 | Non-blocking waits for child processes (or pseudo-processes) are
|
---|
545 | supported via C<waitpid($pid, &POSIX::WNOHANG)>.
|
---|
546 |
|
---|
547 | =item *
|
---|
548 |
|
---|
549 | A memory leak in accept() has been fixed.
|
---|
550 |
|
---|
551 | =item *
|
---|
552 |
|
---|
553 | wait(), waitpid() and backticks now return the correct exit status under
|
---|
554 | Windows 9x.
|
---|
555 |
|
---|
556 | =item *
|
---|
557 |
|
---|
558 | Trailing new %ENV entries weren't propagated to child processes. This
|
---|
559 | is now fixed.
|
---|
560 |
|
---|
561 | =item *
|
---|
562 |
|
---|
563 | Current directory entries in %ENV are now correctly propagated to child
|
---|
564 | processes.
|
---|
565 |
|
---|
566 | =item *
|
---|
567 |
|
---|
568 | Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
|
---|
569 |
|
---|
570 | =item *
|
---|
571 |
|
---|
572 | The makefiles now provide a single switch to bulk-enable all the features
|
---|
573 | enabled in ActiveState ActivePerl (a popular binary distribution).
|
---|
574 |
|
---|
575 | =item *
|
---|
576 |
|
---|
577 | Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root.
|
---|
578 | Other bugs in chdir() and Cwd::cwd() have also been fixed.
|
---|
579 |
|
---|
580 | =item *
|
---|
581 |
|
---|
582 | fork() correctly returns undef and sets EAGAIN when it runs out of
|
---|
583 | pseudo-process handles.
|
---|
584 |
|
---|
585 | =item *
|
---|
586 |
|
---|
587 | ExtUtils::MakeMaker now uses $ENV{LIB} to search for libraries.
|
---|
588 |
|
---|
589 | =item *
|
---|
590 |
|
---|
591 | UNC path handling is better when perl is built to support fork().
|
---|
592 |
|
---|
593 | =item *
|
---|
594 |
|
---|
595 | A handle leak in socket handling has been fixed.
|
---|
596 |
|
---|
597 | =item *
|
---|
598 |
|
---|
599 | send() works from within a pseudo-process.
|
---|
600 |
|
---|
601 | =back
|
---|
602 |
|
---|
603 | Unless specifically qualified otherwise, the remainder of this document
|
---|
604 | covers changes between the 5.005 and 5.6.0 releases.
|
---|
605 |
|
---|
606 | =head1 Core Enhancements
|
---|
607 |
|
---|
608 | =head2 Interpreter cloning, threads, and concurrency
|
---|
609 |
|
---|
610 | Perl 5.6.0 introduces the beginnings of support for running multiple
|
---|
611 | interpreters concurrently in different threads. In conjunction with
|
---|
612 | the perl_clone() API call, which can be used to selectively duplicate
|
---|
613 | the state of any given interpreter, it is possible to compile a
|
---|
614 | piece of code once in an interpreter, clone that interpreter
|
---|
615 | one or more times, and run all the resulting interpreters in distinct
|
---|
616 | threads.
|
---|
617 |
|
---|
618 | On the Windows platform, this feature is used to emulate fork() at the
|
---|
619 | interpreter level. See L<perlfork> for details about that.
|
---|
620 |
|
---|
621 | This feature is still in evolution. It is eventually meant to be used
|
---|
622 | to selectively clone a subroutine and data reachable from that
|
---|
623 | subroutine in a separate interpreter and run the cloned subroutine
|
---|
624 | in a separate thread. Since there is no shared data between the
|
---|
625 | interpreters, little or no locking will be needed (unless parts of
|
---|
626 | the symbol table are explicitly shared). This is obviously intended
|
---|
627 | to be an easy-to-use replacement for the existing threads support.
|
---|
628 |
|
---|
629 | Support for cloning interpreters and interpreter concurrency can be
|
---|
630 | enabled using the -Dusethreads Configure option (see win32/Makefile for
|
---|
631 | how to enable it on Windows.) The resulting perl executable will be
|
---|
632 | functionally identical to one that was built with -Dmultiplicity, but
|
---|
633 | the perl_clone() API call will only be available in the former.
|
---|
634 |
|
---|
635 | -Dusethreads enables the cpp macro USE_ITHREADS by default, which in turn
|
---|
636 | enables Perl source code changes that provide a clear separation between
|
---|
637 | the op tree and the data it operates with. The former is immutable, and
|
---|
638 | can therefore be shared between an interpreter and all of its clones,
|
---|
639 | while the latter is considered local to each interpreter, and is therefore
|
---|
640 | copied for each clone.
|
---|
641 |
|
---|
642 | Note that building Perl with the -Dusemultiplicity Configure option
|
---|
643 | is adequate if you wish to run multiple B<independent> interpreters
|
---|
644 | concurrently in different threads. -Dusethreads only provides the
|
---|
645 | additional functionality of the perl_clone() API call and other
|
---|
646 | support for running B<cloned> interpreters concurrently.
|
---|
647 |
|
---|
648 | NOTE: This is an experimental feature. Implementation details are
|
---|
649 | subject to change.
|
---|
650 |
|
---|
651 | =head2 Lexically scoped warning categories
|
---|
652 |
|
---|
653 | You can now control the granularity of warnings emitted by perl at a finer
|
---|
654 | level using the C<use warnings> pragma. L<warnings> and L<perllexwarn>
|
---|
655 | have copious documentation on this feature.
|
---|
656 |
|
---|
657 | =head2 Unicode and UTF-8 support
|
---|
658 |
|
---|
659 | Perl now uses UTF-8 as its internal representation for character
|
---|
660 | strings. The C<utf8> and C<bytes> pragmas are used to control this support
|
---|
661 | in the current lexical scope. See L<perlunicode>, L<utf8> and L<bytes> for
|
---|
662 | more information.
|
---|
663 |
|
---|
664 | This feature is expected to evolve quickly to support some form of I/O
|
---|
665 | disciplines that can be used to specify the kind of input and output data
|
---|
666 | (bytes or characters). Until that happens, additional modules from CPAN
|
---|
667 | will be needed to complete the toolkit for dealing with Unicode.
|
---|
668 |
|
---|
669 | NOTE: This should be considered an experimental feature. Implementation
|
---|
670 | details are subject to change.
|
---|
671 |
|
---|
672 | =head2 Support for interpolating named characters
|
---|
673 |
|
---|
674 | The new C<\N> escape interpolates named characters within strings.
|
---|
675 | For example, C<"Hi! \N{WHITE SMILING FACE}"> evaluates to a string
|
---|
676 | with a Unicode smiley face at the end.
|
---|
677 |
|
---|
678 | =head2 "our" declarations
|
---|
679 |
|
---|
680 | An "our" declaration introduces a value that can be best understood
|
---|
681 | as a lexically scoped symbolic alias to a global variable in the
|
---|
682 | package that was current where the variable was declared. This is
|
---|
683 | mostly useful as an alternative to the C<vars> pragma, but also provides
|
---|
684 | the opportunity to introduce typing and other attributes for such
|
---|
685 | variables. See L<perlfunc/our>.
|
---|
686 |
|
---|
687 | =head2 Support for strings represented as a vector of ordinals
|
---|
688 |
|
---|
689 | Literals of the form C<v1.2.3.4> are now parsed as a string composed
|
---|
690 | of characters with the specified ordinals. This is an alternative, more
|
---|
691 | readable way to construct (possibly Unicode) strings instead of
|
---|
692 | interpolating characters, as in C<"\x{1}\x{2}\x{3}\x{4}">. The leading
|
---|
693 | C<v> may be omitted if there are more than two ordinals, so C<1.2.3> is
|
---|
694 | parsed the same as C<v1.2.3>.
|
---|
695 |
|
---|
696 | Strings written in this form are also useful to represent version "numbers".
|
---|
697 | It is easy to compare such version "numbers" (which are really just plain
|
---|
698 | strings) using any of the usual string comparison operators C<eq>, C<ne>,
|
---|
699 | C<lt>, C<gt>, etc., or perform bitwise string operations on them using C<|>,
|
---|
700 | C<&>, etc.
|
---|
701 |
|
---|
702 | In conjunction with the new C<$^V> magic variable (which contains
|
---|
703 | the perl version as a string), such literals can be used as a readable way
|
---|
704 | to check if you're running a particular version of Perl:
|
---|
705 |
|
---|
706 | # this will parse in older versions of Perl also
|
---|
707 | if ($^V and $^V gt v5.6.0) {
|
---|
708 | # new features supported
|
---|
709 | }
|
---|
710 |
|
---|
711 | C<require> and C<use> also have some special magic to support such literals.
|
---|
712 | They will be interpreted as a version rather than as a module name:
|
---|
713 |
|
---|
714 | require v5.6.0; # croak if $^V lt v5.6.0
|
---|
715 | use v5.6.0; # same, but croaks at compile-time
|
---|
716 |
|
---|
717 | Alternatively, the C<v> may be omitted if there is more than one dot:
|
---|
718 |
|
---|
719 | require 5.6.0;
|
---|
720 | use 5.6.0;
|
---|
721 |
|
---|
722 | Also, C<sprintf> and C<printf> support the Perl-specific format flag C<%v>
|
---|
723 | to print ordinals of characters in arbitrary strings:
|
---|
724 |
|
---|
725 | printf "v%vd", $^V; # prints current version, such as "v5.5.650"
|
---|
726 | printf "%*vX", ":", $addr; # formats IPv6 address
|
---|
727 | printf "%*vb", " ", $bits; # displays bitstring
|
---|
728 |
|
---|
729 | See L<perldata/"Scalar value constructors"> for additional information.
|
---|
730 |
|
---|
731 | =head2 Improved Perl version numbering system
|
---|
732 |
|
---|
733 | Beginning with Perl version 5.6.0, the version number convention has been
|
---|
734 | changed to a "dotted integer" scheme that is more commonly found in open
|
---|
735 | source projects.
|
---|
736 |
|
---|
737 | Maintenance versions of v5.6.0 will be released as v5.6.1, v5.6.2 etc.
|
---|
738 | The next development series following v5.6.0 will be numbered v5.7.x,
|
---|
739 | beginning with v5.7.0, and the next major production release following
|
---|
740 | v5.6.0 will be v5.8.0.
|
---|
741 |
|
---|
742 | The English module now sets $PERL_VERSION to $^V (a string value) rather
|
---|
743 | than C<$]> (a numeric value). (This is a potential incompatibility.
|
---|
744 | Send us a report via perlbug if you are affected by this.)
|
---|
745 |
|
---|
746 | The v1.2.3 syntax is also now legal in Perl.
|
---|
747 | See L<Support for strings represented as a vector of ordinals> for more on that.
|
---|
748 |
|
---|
749 | To cope with the new versioning system's use of at least three significant
|
---|
750 | digits for each version component, the method used for incrementing the
|
---|
751 | subversion number has also changed slightly. We assume that versions older
|
---|
752 | than v5.6.0 have been incrementing the subversion component in multiples of
|
---|
753 | 10. Versions after v5.6.0 will increment them by 1. Thus, using the new
|
---|
754 | notation, 5.005_03 is the "same" as v5.5.30, and the first maintenance
|
---|
755 | version following v5.6.0 will be v5.6.1 (which should be read as being
|
---|
756 | equivalent to a floating point value of 5.006_001 in the older format,
|
---|
757 | stored in C<$]>).
|
---|
758 |
|
---|
759 | =head2 New syntax for declaring subroutine attributes
|
---|
760 |
|
---|
761 | Formerly, if you wanted to mark a subroutine as being a method call or
|
---|
762 | as requiring an automatic lock() when it is entered, you had to declare
|
---|
763 | that with a C<use attrs> pragma in the body of the subroutine.
|
---|
764 | That can now be accomplished with declaration syntax, like this:
|
---|
765 |
|
---|
766 | sub mymethod : locked method;
|
---|
767 | ...
|
---|
768 | sub mymethod : locked method {
|
---|
769 | ...
|
---|
770 | }
|
---|
771 |
|
---|
772 | sub othermethod :locked :method;
|
---|
773 | ...
|
---|
774 | sub othermethod :locked :method {
|
---|
775 | ...
|
---|
776 | }
|
---|
777 |
|
---|
778 |
|
---|
779 | (Note how only the first C<:> is mandatory, and whitespace surrounding
|
---|
780 | the C<:> is optional.)
|
---|
781 |
|
---|
782 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes
|
---|
783 | with the stubs they provide. See L<attributes>.
|
---|
784 |
|
---|
785 | =head2 File and directory handles can be autovivified
|
---|
786 |
|
---|
787 | Similar to how constructs such as C<< $x->[0] >> autovivify a reference,
|
---|
788 | handle constructors (open(), opendir(), pipe(), socketpair(), sysopen(),
|
---|
789 | socket(), and accept()) now autovivify a file or directory handle
|
---|
790 | if the handle passed to them is an uninitialized scalar variable. This
|
---|
791 | allows the constructs such as C<open(my $fh, ...)> and C<open(local $fh,...)>
|
---|
792 | to be used to create filehandles that will conveniently be closed
|
---|
793 | automatically when the scope ends, provided there are no other references
|
---|
794 | to them. This largely eliminates the need for typeglobs when opening
|
---|
795 | filehandles that must be passed around, as in the following example:
|
---|
796 |
|
---|
797 | sub myopen {
|
---|
798 | open my $fh, "@_"
|
---|
799 | or die "Can't open '@_': $!";
|
---|
800 | return $fh;
|
---|
801 | }
|
---|
802 |
|
---|
803 | {
|
---|
804 | my $f = myopen("</etc/motd");
|
---|
805 | print <$f>;
|
---|
806 | # $f implicitly closed here
|
---|
807 | }
|
---|
808 |
|
---|
809 | =head2 open() with more than two arguments
|
---|
810 |
|
---|
811 | If open() is passed three arguments instead of two, the second argument
|
---|
812 | is used as the mode and the third argument is taken to be the file name.
|
---|
813 | This is primarily useful for protecting against unintended magic behavior
|
---|
814 | of the traditional two-argument form. See L<perlfunc/open>.
|
---|
815 |
|
---|
816 | =head2 64-bit support
|
---|
817 |
|
---|
818 | Any platform that has 64-bit integers either
|
---|
819 |
|
---|
820 | (1) natively as longs or ints
|
---|
821 | (2) via special compiler flags
|
---|
822 | (3) using long long or int64_t
|
---|
823 |
|
---|
824 | is able to use "quads" (64-bit integers) as follows:
|
---|
825 |
|
---|
826 | =over 4
|
---|
827 |
|
---|
828 | =item *
|
---|
829 |
|
---|
830 | constants (decimal, hexadecimal, octal, binary) in the code
|
---|
831 |
|
---|
832 | =item *
|
---|
833 |
|
---|
834 | arguments to oct() and hex()
|
---|
835 |
|
---|
836 | =item *
|
---|
837 |
|
---|
838 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q)
|
---|
839 |
|
---|
840 | =item *
|
---|
841 |
|
---|
842 | printed as such
|
---|
843 |
|
---|
844 | =item *
|
---|
845 |
|
---|
846 | pack() and unpack() "q" and "Q" formats
|
---|
847 |
|
---|
848 | =item *
|
---|
849 |
|
---|
850 | in basic arithmetics: + - * / % (NOTE: operating close to the limits
|
---|
851 | of the integer values may produce surprising results)
|
---|
852 |
|
---|
853 | =item *
|
---|
854 |
|
---|
855 | in bit arithmetics: & | ^ ~ << >> (NOTE: these used to be forced
|
---|
856 | to be 32 bits wide but now operate on the full native width.)
|
---|
857 |
|
---|
858 | =item *
|
---|
859 |
|
---|
860 | vec()
|
---|
861 |
|
---|
862 | =back
|
---|
863 |
|
---|
864 | Note that unless you have the case (a) you will have to configure
|
---|
865 | and compile Perl using the -Duse64bitint Configure flag.
|
---|
866 |
|
---|
867 | NOTE: The Configure flags -Duselonglong and -Duse64bits have been
|
---|
868 | deprecated. Use -Duse64bitint instead.
|
---|
869 |
|
---|
870 | There are actually two modes of 64-bitness: the first one is achieved
|
---|
871 | using Configure -Duse64bitint and the second one using Configure
|
---|
872 | -Duse64bitall. The difference is that the first one is minimal and
|
---|
873 | the second one maximal. The first works in more places than the second.
|
---|
874 |
|
---|
875 | The C<use64bitint> does only as much as is required to get 64-bit
|
---|
876 | integers into Perl (this may mean, for example, using "long longs")
|
---|
877 | while your memory may still be limited to 2 gigabytes (because your
|
---|
878 | pointers could still be 32-bit). Note that the name C<64bitint> does
|
---|
879 | not imply that your C compiler will be using 64-bit C<int>s (it might,
|
---|
880 | but it doesn't have to): the C<use64bitint> means that you will be
|
---|
881 | able to have 64 bits wide scalar values.
|
---|
882 |
|
---|
883 | The C<use64bitall> goes all the way by attempting to switch also
|
---|
884 | integers (if it can), longs (and pointers) to being 64-bit. This may
|
---|
885 | create an even more binary incompatible Perl than -Duse64bitint: the
|
---|
886 | resulting executable may not run at all in a 32-bit box, or you may
|
---|
887 | have to reboot/reconfigure/rebuild your operating system to be 64-bit
|
---|
888 | aware.
|
---|
889 |
|
---|
890 | Natively 64-bit systems like Alpha and Cray need neither -Duse64bitint
|
---|
891 | nor -Duse64bitall.
|
---|
892 |
|
---|
893 | Last but not least: note that due to Perl's habit of always using
|
---|
894 | floating point numbers, the quads are still not true integers.
|
---|
895 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned,
|
---|
896 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they
|
---|
897 | are silently promoted to floating point numbers, after which they will
|
---|
898 | start losing precision (in their lower digits).
|
---|
899 |
|
---|
900 | NOTE: 64-bit support is still experimental on most platforms.
|
---|
901 | Existing support only covers the LP64 data model. In particular, the
|
---|
902 | LLP64 data model is not yet supported. 64-bit libraries and system
|
---|
903 | APIs on many platforms have not stabilized--your mileage may vary.
|
---|
904 |
|
---|
905 | =head2 Large file support
|
---|
906 |
|
---|
907 | If you have filesystems that support "large files" (files larger than
|
---|
908 | 2 gigabytes), you may now also be able to create and access them from
|
---|
909 | Perl.
|
---|
910 |
|
---|
911 | NOTE: The default action is to enable large file support, if
|
---|
912 | available on the platform.
|
---|
913 |
|
---|
914 | If the large file support is on, and you have a Fcntl constant
|
---|
915 | O_LARGEFILE, the O_LARGEFILE is automatically added to the flags
|
---|
916 | of sysopen().
|
---|
917 |
|
---|
918 | Beware that unless your filesystem also supports "sparse files" seeking
|
---|
919 | to umpteen petabytes may be inadvisable.
|
---|
920 |
|
---|
921 | Note that in addition to requiring a proper file system to do large
|
---|
922 | files you may also need to adjust your per-process (or your
|
---|
923 | per-system, or per-process-group, or per-user-group) maximum filesize
|
---|
924 | limits before running Perl scripts that try to handle large files,
|
---|
925 | especially if you intend to write such files.
|
---|
926 |
|
---|
927 | Finally, in addition to your process/process group maximum filesize
|
---|
928 | limits, you may have quota limits on your filesystems that stop you
|
---|
929 | (your user id or your user group id) from using large files.
|
---|
930 |
|
---|
931 | Adjusting your process/user/group/file system/operating system limits
|
---|
932 | is outside the scope of Perl core language. For process limits, you
|
---|
933 | may try increasing the limits using your shell's limits/limit/ulimit
|
---|
934 | command before running Perl. The BSD::Resource extension (not
|
---|
935 | included with the standard Perl distribution) may also be of use, it
|
---|
936 | offers the getrlimit/setrlimit interface that can be used to adjust
|
---|
937 | process resource usage limits, including the maximum filesize limit.
|
---|
938 |
|
---|
939 | =head2 Long doubles
|
---|
940 |
|
---|
941 | In some systems you may be able to use long doubles to enhance the
|
---|
942 | range and precision of your double precision floating point numbers
|
---|
943 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable
|
---|
944 | this support (if it is available).
|
---|
945 |
|
---|
946 | =head2 "more bits"
|
---|
947 |
|
---|
948 | You can "Configure -Dusemorebits" to turn on both the 64-bit support
|
---|
949 | and the long double support.
|
---|
950 |
|
---|
951 | =head2 Enhanced support for sort() subroutines
|
---|
952 |
|
---|
953 | Perl subroutines with a prototype of C<($$)>, and XSUBs in general, can
|
---|
954 | now be used as sort subroutines. In either case, the two elements to
|
---|
955 | be compared are passed as normal parameters in @_. See L<perlfunc/sort>.
|
---|
956 |
|
---|
957 | For unprototyped sort subroutines, the historical behavior of passing
|
---|
958 | the elements to be compared as the global variables $a and $b remains
|
---|
959 | unchanged.
|
---|
960 |
|
---|
961 | =head2 C<sort $coderef @foo> allowed
|
---|
962 |
|
---|
963 | sort() did not accept a subroutine reference as the comparison
|
---|
964 | function in earlier versions. This is now permitted.
|
---|
965 |
|
---|
966 | =head2 File globbing implemented internally
|
---|
967 |
|
---|
968 | Perl now uses the File::Glob implementation of the glob() operator
|
---|
969 | automatically. This avoids using an external csh process and the
|
---|
970 | problems associated with it.
|
---|
971 |
|
---|
972 | NOTE: This is currently an experimental feature. Interfaces and
|
---|
973 | implementation are subject to change.
|
---|
974 |
|
---|
975 | =head2 Support for CHECK blocks
|
---|
976 |
|
---|
977 | In addition to C<BEGIN>, C<INIT>, C<END>, C<DESTROY> and C<AUTOLOAD>,
|
---|
978 | subroutines named C<CHECK> are now special. These are queued up during
|
---|
979 | compilation and behave similar to END blocks, except they are called at
|
---|
980 | the end of compilation rather than at the end of execution. They cannot
|
---|
981 | be called directly.
|
---|
982 |
|
---|
983 | =head2 POSIX character class syntax [: :] supported
|
---|
984 |
|
---|
985 | For example to match alphabetic characters use /[[:alpha:]]/.
|
---|
986 | See L<perlre> for details.
|
---|
987 |
|
---|
988 | =head2 Better pseudo-random number generator
|
---|
989 |
|
---|
990 | In 5.005_0x and earlier, perl's rand() function used the C library
|
---|
991 | rand(3) function. As of 5.005_52, Configure tests for drand48(),
|
---|
992 | random(), and rand() (in that order) and picks the first one it finds.
|
---|
993 |
|
---|
994 | These changes should result in better random numbers from rand().
|
---|
995 |
|
---|
996 | =head2 Improved C<qw//> operator
|
---|
997 |
|
---|
998 | The C<qw//> operator is now evaluated at compile time into a true list
|
---|
999 | instead of being replaced with a run time call to C<split()>. This
|
---|
1000 | removes the confusing misbehaviour of C<qw//> in scalar context, which
|
---|
1001 | had inherited that behaviour from split().
|
---|
1002 |
|
---|
1003 | Thus:
|
---|
1004 |
|
---|
1005 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n";
|
---|
1006 |
|
---|
1007 | now correctly prints "3|a", instead of "2|a".
|
---|
1008 |
|
---|
1009 | =head2 Better worst-case behavior of hashes
|
---|
1010 |
|
---|
1011 | Small changes in the hashing algorithm have been implemented in
|
---|
1012 | order to improve the distribution of lower order bits in the
|
---|
1013 | hashed value. This is expected to yield better performance on
|
---|
1014 | keys that are repeated sequences.
|
---|
1015 |
|
---|
1016 | =head2 pack() format 'Z' supported
|
---|
1017 |
|
---|
1018 | The new format type 'Z' is useful for packing and unpacking null-terminated
|
---|
1019 | strings. See L<perlfunc/"pack">.
|
---|
1020 |
|
---|
1021 | =head2 pack() format modifier '!' supported
|
---|
1022 |
|
---|
1023 | The new format type modifier '!' is useful for packing and unpacking
|
---|
1024 | native shorts, ints, and longs. See L<perlfunc/"pack">.
|
---|
1025 |
|
---|
1026 | =head2 pack() and unpack() support counted strings
|
---|
1027 |
|
---|
1028 | The template character '/' can be used to specify a counted string
|
---|
1029 | type to be packed or unpacked. See L<perlfunc/"pack">.
|
---|
1030 |
|
---|
1031 | =head2 Comments in pack() templates
|
---|
1032 |
|
---|
1033 | The '#' character in a template introduces a comment up to
|
---|
1034 | end of the line. This facilitates documentation of pack()
|
---|
1035 | templates.
|
---|
1036 |
|
---|
1037 | =head2 Weak references
|
---|
1038 |
|
---|
1039 | In previous versions of Perl, you couldn't cache objects so as
|
---|
1040 | to allow them to be deleted if the last reference from outside
|
---|
1041 | the cache is deleted. The reference in the cache would hold a
|
---|
1042 | reference count on the object and the objects would never be
|
---|
1043 | destroyed.
|
---|
1044 |
|
---|
1045 | Another familiar problem is with circular references. When an
|
---|
1046 | object references itself, its reference count would never go
|
---|
1047 | down to zero, and it would not get destroyed until the program
|
---|
1048 | is about to exit.
|
---|
1049 |
|
---|
1050 | Weak references solve this by allowing you to "weaken" any
|
---|
1051 | reference, that is, make it not count towards the reference count.
|
---|
1052 | When the last non-weak reference to an object is deleted, the object
|
---|
1053 | is destroyed and all the weak references to the object are
|
---|
1054 | automatically undef-ed.
|
---|
1055 |
|
---|
1056 | To use this feature, you need the Devel::WeakRef package from CPAN, which
|
---|
1057 | contains additional documentation.
|
---|
1058 |
|
---|
1059 | NOTE: This is an experimental feature. Details are subject to change.
|
---|
1060 |
|
---|
1061 | =head2 Binary numbers supported
|
---|
1062 |
|
---|
1063 | Binary numbers are now supported as literals, in s?printf formats, and
|
---|
1064 | C<oct()>:
|
---|
1065 |
|
---|
1066 | $answer = 0b101010;
|
---|
1067 | printf "The answer is: %b\n", oct("0b101010");
|
---|
1068 |
|
---|
1069 | =head2 Lvalue subroutines
|
---|
1070 |
|
---|
1071 | Subroutines can now return modifiable lvalues.
|
---|
1072 | See L<perlsub/"Lvalue subroutines">.
|
---|
1073 |
|
---|
1074 | NOTE: This is an experimental feature. Details are subject to change.
|
---|
1075 |
|
---|
1076 | =head2 Some arrows may be omitted in calls through references
|
---|
1077 |
|
---|
1078 | Perl now allows the arrow to be omitted in many constructs
|
---|
1079 | involving subroutine calls through references. For example,
|
---|
1080 | C<< $foo[10]->('foo') >> may now be written C<$foo[10]('foo')>.
|
---|
1081 | This is rather similar to how the arrow may be omitted from
|
---|
1082 | C<< $foo[10]->{'foo'} >>. Note however, that the arrow is still
|
---|
1083 | required for C<< foo(10)->('bar') >>.
|
---|
1084 |
|
---|
1085 | =head2 Boolean assignment operators are legal lvalues
|
---|
1086 |
|
---|
1087 | Constructs such as C<($a ||= 2) += 1> are now allowed.
|
---|
1088 |
|
---|
1089 | =head2 exists() is supported on subroutine names
|
---|
1090 |
|
---|
1091 | The exists() builtin now works on subroutine names. A subroutine
|
---|
1092 | is considered to exist if it has been declared (even if implicitly).
|
---|
1093 | See L<perlfunc/exists> for examples.
|
---|
1094 |
|
---|
1095 | =head2 exists() and delete() are supported on array elements
|
---|
1096 |
|
---|
1097 | The exists() and delete() builtins now work on simple arrays as well.
|
---|
1098 | The behavior is similar to that on hash elements.
|
---|
1099 |
|
---|
1100 | exists() can be used to check whether an array element has been
|
---|
1101 | initialized. This avoids autovivifying array elements that don't exist.
|
---|
1102 | If the array is tied, the EXISTS() method in the corresponding tied
|
---|
1103 | package will be invoked.
|
---|
1104 |
|
---|
1105 | delete() may be used to remove an element from the array and return
|
---|
1106 | it. The array element at that position returns to its uninitialized
|
---|
1107 | state, so that testing for the same element with exists() will return
|
---|
1108 | false. If the element happens to be the one at the end, the size of
|
---|
1109 | the array also shrinks up to the highest element that tests true for
|
---|
1110 | exists(), or 0 if none such is found. If the array is tied, the DELETE()
|
---|
1111 | method in the corresponding tied package will be invoked.
|
---|
1112 |
|
---|
1113 | See L<perlfunc/exists> and L<perlfunc/delete> for examples.
|
---|
1114 |
|
---|
1115 | =head2 Pseudo-hashes work better
|
---|
1116 |
|
---|
1117 | Dereferencing some types of reference values in a pseudo-hash,
|
---|
1118 | such as C<< $ph->{foo}[1] >>, was accidentally disallowed. This has
|
---|
1119 | been corrected.
|
---|
1120 |
|
---|
1121 | When applied to a pseudo-hash element, exists() now reports whether
|
---|
1122 | the specified value exists, not merely if the key is valid.
|
---|
1123 |
|
---|
1124 | delete() now works on pseudo-hashes. When given a pseudo-hash element
|
---|
1125 | or slice it deletes the values corresponding to the keys (but not the keys
|
---|
1126 | themselves). See L<perlref/"Pseudo-hashes: Using an array as a hash">.
|
---|
1127 |
|
---|
1128 | Pseudo-hash slices with constant keys are now optimized to array lookups
|
---|
1129 | at compile-time.
|
---|
1130 |
|
---|
1131 | List assignments to pseudo-hash slices are now supported.
|
---|
1132 |
|
---|
1133 | The C<fields> pragma now provides ways to create pseudo-hashes, via
|
---|
1134 | fields::new() and fields::phash(). See L<fields>.
|
---|
1135 |
|
---|
1136 | NOTE: The pseudo-hash data type continues to be experimental.
|
---|
1137 | Limiting oneself to the interface elements provided by the
|
---|
1138 | fields pragma will provide protection from any future changes.
|
---|
1139 |
|
---|
1140 | =head2 Automatic flushing of output buffers
|
---|
1141 |
|
---|
1142 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers
|
---|
1143 | of all files opened for output when the operation was attempted. This
|
---|
1144 | mostly eliminates confusing buffering mishaps suffered by users unaware
|
---|
1145 | of how Perl internally handles I/O.
|
---|
1146 |
|
---|
1147 | This is not supported on some platforms like Solaris where a suitably
|
---|
1148 | correct implementation of fflush(NULL) isn't available.
|
---|
1149 |
|
---|
1150 | =head2 Better diagnostics on meaningless filehandle operations
|
---|
1151 |
|
---|
1152 | Constructs such as C<< open(<FH>) >> and C<< close(<FH>) >>
|
---|
1153 | are compile time errors. Attempting to read from filehandles that
|
---|
1154 | were opened only for writing will now produce warnings (just as
|
---|
1155 | writing to read-only filehandles does).
|
---|
1156 |
|
---|
1157 | =head2 Where possible, buffered data discarded from duped input filehandle
|
---|
1158 |
|
---|
1159 | C<< open(NEW, "<&OLD") >> now attempts to discard any data that
|
---|
1160 | was previously read and buffered in C<OLD> before duping the handle.
|
---|
1161 | On platforms where doing this is allowed, the next read operation
|
---|
1162 | on C<NEW> will return the same data as the corresponding operation
|
---|
1163 | on C<OLD>. Formerly, it would have returned the data from the start
|
---|
1164 | of the following disk block instead.
|
---|
1165 |
|
---|
1166 | =head2 eof() has the same old magic as <>
|
---|
1167 |
|
---|
1168 | C<eof()> would return true if no attempt to read from C<< <> >> had
|
---|
1169 | yet been made. C<eof()> has been changed to have a little magic of its
|
---|
1170 | own, it now opens the C<< <> >> files.
|
---|
1171 |
|
---|
1172 | =head2 binmode() can be used to set :crlf and :raw modes
|
---|
1173 |
|
---|
1174 | binmode() now accepts a second argument that specifies a discipline
|
---|
1175 | for the handle in question. The two pseudo-disciplines ":raw" and
|
---|
1176 | ":crlf" are currently supported on DOS-derivative platforms.
|
---|
1177 | See L<perlfunc/"binmode"> and L<open>.
|
---|
1178 |
|
---|
1179 | =head2 C<-T> filetest recognizes UTF-8 encoded files as "text"
|
---|
1180 |
|
---|
1181 | The algorithm used for the C<-T> filetest has been enhanced to
|
---|
1182 | correctly identify UTF-8 content as "text".
|
---|
1183 |
|
---|
1184 | =head2 system(), backticks and pipe open now reflect exec() failure
|
---|
1185 |
|
---|
1186 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |")
|
---|
1187 | etc., are implemented via fork() and exec(). When the underlying
|
---|
1188 | exec() fails, earlier versions did not report the error properly,
|
---|
1189 | since the exec() happened to be in a different process.
|
---|
1190 |
|
---|
1191 | The child process now communicates with the parent about the
|
---|
1192 | error in launching the external command, which allows these
|
---|
1193 | constructs to return with their usual error value and set $!.
|
---|
1194 |
|
---|
1195 | =head2 Improved diagnostics
|
---|
1196 |
|
---|
1197 | Line numbers are no longer suppressed (under most likely circumstances)
|
---|
1198 | during the global destruction phase.
|
---|
1199 |
|
---|
1200 | Diagnostics emitted from code running in threads other than the main
|
---|
1201 | thread are now accompanied by the thread ID.
|
---|
1202 |
|
---|
1203 | Embedded null characters in diagnostics now actually show up. They
|
---|
1204 | used to truncate the message in prior versions.
|
---|
1205 |
|
---|
1206 | $foo::a and $foo::b are now exempt from "possible typo" warnings only
|
---|
1207 | if sort() is encountered in package C<foo>.
|
---|
1208 |
|
---|
1209 | Unrecognized alphabetic escapes encountered when parsing quote
|
---|
1210 | constructs now generate a warning, since they may take on new
|
---|
1211 | semantics in later versions of Perl.
|
---|
1212 |
|
---|
1213 | Many diagnostics now report the internal operation in which the warning
|
---|
1214 | was provoked, like so:
|
---|
1215 |
|
---|
1216 | Use of uninitialized value in concatenation (.) at (eval 1) line 1.
|
---|
1217 | Use of uninitialized value in print at (eval 1) line 1.
|
---|
1218 |
|
---|
1219 | Diagnostics that occur within eval may also report the file and line
|
---|
1220 | number where the eval is located, in addition to the eval sequence
|
---|
1221 | number and the line number within the evaluated text itself. For
|
---|
1222 | example:
|
---|
1223 |
|
---|
1224 | Not enough arguments for scalar at (eval 4)[newlib/perl5db.pl:1411] line 2, at EOF
|
---|
1225 |
|
---|
1226 | =head2 Diagnostics follow STDERR
|
---|
1227 |
|
---|
1228 | Diagnostic output now goes to whichever file the C<STDERR> handle
|
---|
1229 | is pointing at, instead of always going to the underlying C runtime
|
---|
1230 | library's C<stderr>.
|
---|
1231 |
|
---|
1232 | =head2 More consistent close-on-exec behavior
|
---|
1233 |
|
---|
1234 | On systems that support a close-on-exec flag on filehandles, the
|
---|
1235 | flag is now set for any handles created by pipe(), socketpair(),
|
---|
1236 | socket(), and accept(), if that is warranted by the value of $^F
|
---|
1237 | that may be in effect. Earlier versions neglected to set the flag
|
---|
1238 | for handles created with these operators. See L<perlfunc/pipe>,
|
---|
1239 | L<perlfunc/socketpair>, L<perlfunc/socket>, L<perlfunc/accept>,
|
---|
1240 | and L<perlvar/$^F>.
|
---|
1241 |
|
---|
1242 | =head2 syswrite() ease-of-use
|
---|
1243 |
|
---|
1244 | The length argument of C<syswrite()> has become optional.
|
---|
1245 |
|
---|
1246 | =head2 Better syntax checks on parenthesized unary operators
|
---|
1247 |
|
---|
1248 | Expressions such as:
|
---|
1249 |
|
---|
1250 | print defined(&foo,&bar,&baz);
|
---|
1251 | print uc("foo","bar","baz");
|
---|
1252 | undef($foo,&bar);
|
---|
1253 |
|
---|
1254 | used to be accidentally allowed in earlier versions, and produced
|
---|
1255 | unpredictable behaviour. Some produced ancillary warnings
|
---|
1256 | when used in this way; others silently did the wrong thing.
|
---|
1257 |
|
---|
1258 | The parenthesized forms of most unary operators that expect a single
|
---|
1259 | argument now ensure that they are not called with more than one
|
---|
1260 | argument, making the cases shown above syntax errors. The usual
|
---|
1261 | behaviour of:
|
---|
1262 |
|
---|
1263 | print defined &foo, &bar, &baz;
|
---|
1264 | print uc "foo", "bar", "baz";
|
---|
1265 | undef $foo, &bar;
|
---|
1266 |
|
---|
1267 | remains unchanged. See L<perlop>.
|
---|
1268 |
|
---|
1269 | =head2 Bit operators support full native integer width
|
---|
1270 |
|
---|
1271 | The bit operators (& | ^ ~ << >>) now operate on the full native
|
---|
1272 | integral width (the exact size of which is available in $Config{ivsize}).
|
---|
1273 | For example, if your platform is either natively 64-bit or if Perl
|
---|
1274 | has been configured to use 64-bit integers, these operations apply
|
---|
1275 | to 8 bytes (as opposed to 4 bytes on 32-bit platforms).
|
---|
1276 | For portability, be sure to mask off the excess bits in the result of
|
---|
1277 | unary C<~>, e.g., C<~$x & 0xffffffff>.
|
---|
1278 |
|
---|
1279 | =head2 Improved security features
|
---|
1280 |
|
---|
1281 | More potentially unsafe operations taint their results for improved
|
---|
1282 | security.
|
---|
1283 |
|
---|
1284 | The C<passwd> and C<shell> fields returned by the getpwent(), getpwnam(),
|
---|
1285 | and getpwuid() are now tainted, because the user can affect their own
|
---|
1286 | encrypted password and login shell.
|
---|
1287 |
|
---|
1288 | The variable modified by shmread(), and messages returned by msgrcv()
|
---|
1289 | (and its object-oriented interface IPC::SysV::Msg::rcv) are also tainted,
|
---|
1290 | because other untrusted processes can modify messages and shared memory
|
---|
1291 | segments for their own nefarious purposes.
|
---|
1292 |
|
---|
1293 | =head2 More functional bareword prototype (*)
|
---|
1294 |
|
---|
1295 | Bareword prototypes have been rationalized to enable them to be used
|
---|
1296 | to override builtins that accept barewords and interpret them in
|
---|
1297 | a special way, such as C<require> or C<do>.
|
---|
1298 |
|
---|
1299 | Arguments prototyped as C<*> will now be visible within the subroutine
|
---|
1300 | as either a simple scalar or as a reference to a typeglob.
|
---|
1301 | See L<perlsub/Prototypes>.
|
---|
1302 |
|
---|
1303 | =head2 C<require> and C<do> may be overridden
|
---|
1304 |
|
---|
1305 | C<require> and C<do 'file'> operations may be overridden locally
|
---|
1306 | by importing subroutines of the same name into the current package
|
---|
1307 | (or globally by importing them into the CORE::GLOBAL:: namespace).
|
---|
1308 | Overriding C<require> will also affect C<use>, provided the override
|
---|
1309 | is visible at compile-time.
|
---|
1310 | See L<perlsub/"Overriding Built-in Functions">.
|
---|
1311 |
|
---|
1312 | =head2 $^X variables may now have names longer than one character
|
---|
1313 |
|
---|
1314 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax
|
---|
1315 | error. Now variable names that begin with a control character may be
|
---|
1316 | arbitrarily long. However, for compatibility reasons, these variables
|
---|
1317 | I<must> be written with explicit braces, as C<${^XY}> for example.
|
---|
1318 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more
|
---|
1319 | than one control character, such as C<${^XY^Z}>, are illegal.
|
---|
1320 |
|
---|
1321 | The old syntax has not changed. As before, `^X' may be either a
|
---|
1322 | literal control-X character or the two-character sequence `caret' plus
|
---|
1323 | `X'. When braces are omitted, the variable name stops after the
|
---|
1324 | control character. Thus C<"$^XYZ"> continues to be synonymous with
|
---|
1325 | C<$^X . "YZ"> as before.
|
---|
1326 |
|
---|
1327 | As before, lexical variables may not have names beginning with control
|
---|
1328 | characters. As before, variables whose names begin with a control
|
---|
1329 | character are always forced to be in package `main'. All such variables
|
---|
1330 | are reserved for future extensions, except those that begin with
|
---|
1331 | C<^_>, which may be used by user programs and are guaranteed not to
|
---|
1332 | acquire special meaning in any future version of Perl.
|
---|
1333 |
|
---|
1334 | =head2 New variable $^C reflects C<-c> switch
|
---|
1335 |
|
---|
1336 | C<$^C> has a boolean value that reflects whether perl is being run
|
---|
1337 | in compile-only mode (i.e. via the C<-c> switch). Since
|
---|
1338 | BEGIN blocks are executed under such conditions, this variable
|
---|
1339 | enables perl code to determine whether actions that make sense
|
---|
1340 | only during normal running are warranted. See L<perlvar>.
|
---|
1341 |
|
---|
1342 | =head2 New variable $^V contains Perl version as a string
|
---|
1343 |
|
---|
1344 | C<$^V> contains the Perl version number as a string composed of
|
---|
1345 | characters whose ordinals match the version numbers, i.e. v5.6.0.
|
---|
1346 | This may be used in string comparisons.
|
---|
1347 |
|
---|
1348 | See C<Support for strings represented as a vector of ordinals> for an
|
---|
1349 | example.
|
---|
1350 |
|
---|
1351 | =head2 Optional Y2K warnings
|
---|
1352 |
|
---|
1353 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined,
|
---|
1354 | it emits optional warnings when concatenating the number 19
|
---|
1355 | with another number.
|
---|
1356 |
|
---|
1357 | This behavior must be specifically enabled when running Configure.
|
---|
1358 | See F<INSTALL> and F<README.Y2K>.
|
---|
1359 |
|
---|
1360 | =head2 Arrays now always interpolate into double-quoted strings
|
---|
1361 |
|
---|
1362 | In double-quoted strings, arrays now interpolate, no matter what. The
|
---|
1363 | behavior in earlier versions of perl 5 was that arrays would interpolate
|
---|
1364 | into strings if the array had been mentioned before the string was
|
---|
1365 | compiled, and otherwise Perl would raise a fatal compile-time error.
|
---|
1366 | In versions 5.000 through 5.003, the error was
|
---|
1367 |
|
---|
1368 | Literal @example now requires backslash
|
---|
1369 |
|
---|
1370 | In versions 5.004_01 through 5.6.0, the error was
|
---|
1371 |
|
---|
1372 | In string, @example now must be written as \@example
|
---|
1373 |
|
---|
1374 | The idea here was to get people into the habit of writing
|
---|
1375 | C<"fred\@example.com"> when they wanted a literal C<@> sign, just as
|
---|
1376 | they have always written C<"Give me back my \$5"> when they wanted a
|
---|
1377 | literal C<$> sign.
|
---|
1378 |
|
---|
1379 | Starting with 5.6.1, when Perl now sees an C<@> sign in a
|
---|
1380 | double-quoted string, it I<always> attempts to interpolate an array,
|
---|
1381 | regardless of whether or not the array has been used or declared
|
---|
1382 | already. The fatal error has been downgraded to an optional warning:
|
---|
1383 |
|
---|
1384 | Possible unintended interpolation of @example in string
|
---|
1385 |
|
---|
1386 | This warns you that C<"[email protected]"> is going to turn into
|
---|
1387 | C<fred.com> if you don't backslash the C<@>.
|
---|
1388 | See http://www.plover.com/~mjd/perl/at-error.html for more details
|
---|
1389 | about the history here.
|
---|
1390 |
|
---|
1391 | =head2 @- and @+ provide starting/ending offsets of regex submatches
|
---|
1392 |
|
---|
1393 | The new magic variables @- and @+ provide the starting and ending
|
---|
1394 | offsets, respectively, of $&, $1, $2, etc. See L<perlvar> for
|
---|
1395 | details.
|
---|
1396 |
|
---|
1397 | =head1 Modules and Pragmata
|
---|
1398 |
|
---|
1399 | =head2 Modules
|
---|
1400 |
|
---|
1401 | =over 4
|
---|
1402 |
|
---|
1403 | =item attributes
|
---|
1404 |
|
---|
1405 | While used internally by Perl as a pragma, this module also
|
---|
1406 | provides a way to fetch subroutine and variable attributes.
|
---|
1407 | See L<attributes>.
|
---|
1408 |
|
---|
1409 | =item B
|
---|
1410 |
|
---|
1411 | The Perl Compiler suite has been extensively reworked for this
|
---|
1412 | release. More of the standard Perl testsuite passes when run
|
---|
1413 | under the Compiler, but there is still a significant way to
|
---|
1414 | go to achieve production quality compiled executables.
|
---|
1415 |
|
---|
1416 | NOTE: The Compiler suite remains highly experimental. The
|
---|
1417 | generated code may not be correct, even when it manages to execute
|
---|
1418 | without errors.
|
---|
1419 |
|
---|
1420 | =item Benchmark
|
---|
1421 |
|
---|
1422 | Overall, Benchmark results exhibit lower average error and better timing
|
---|
1423 | accuracy.
|
---|
1424 |
|
---|
1425 | You can now run tests for I<n> seconds instead of guessing the right
|
---|
1426 | number of tests to run: e.g., timethese(-5, ...) will run each
|
---|
1427 | code for at least 5 CPU seconds. Zero as the "number of repetitions"
|
---|
1428 | means "for at least 3 CPU seconds". The output format has also
|
---|
1429 | changed. For example:
|
---|
1430 |
|
---|
1431 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
|
---|
1432 |
|
---|
1433 | will now output something like this:
|
---|
1434 |
|
---|
1435 | Benchmark: running a, b, each for at least 5 CPU seconds...
|
---|
1436 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
|
---|
1437 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
|
---|
1438 |
|
---|
1439 | New features: "each for at least N CPU seconds...", "wallclock secs",
|
---|
1440 | and the "@ operations/CPU second (n=operations)".
|
---|
1441 |
|
---|
1442 | timethese() now returns a reference to a hash of Benchmark objects containing
|
---|
1443 | the test results, keyed on the names of the tests.
|
---|
1444 |
|
---|
1445 | timethis() now returns the iterations field in the Benchmark result object
|
---|
1446 | instead of 0.
|
---|
1447 |
|
---|
1448 | timethese(), timethis(), and the new cmpthese() (see below) can also take
|
---|
1449 | a format specifier of 'none' to suppress output.
|
---|
1450 |
|
---|
1451 | A new function countit() is just like timeit() except that it takes a
|
---|
1452 | TIME instead of a COUNT.
|
---|
1453 |
|
---|
1454 | A new function cmpthese() prints a chart comparing the results of each test
|
---|
1455 | returned from a timethese() call. For each possible pair of tests, the
|
---|
1456 | percentage speed difference (iters/sec or seconds/iter) is shown.
|
---|
1457 |
|
---|
1458 | For other details, see L<Benchmark>.
|
---|
1459 |
|
---|
1460 | =item ByteLoader
|
---|
1461 |
|
---|
1462 | The ByteLoader is a dedicated extension to generate and run
|
---|
1463 | Perl bytecode. See L<ByteLoader>.
|
---|
1464 |
|
---|
1465 | =item constant
|
---|
1466 |
|
---|
1467 | References can now be used.
|
---|
1468 |
|
---|
1469 | The new version also allows a leading underscore in constant names, but
|
---|
1470 | disallows a double leading underscore (as in "__LINE__"). Some other names
|
---|
1471 | are disallowed or warned against, including BEGIN, END, etc. Some names
|
---|
1472 | which were forced into main:: used to fail silently in some cases; now they're
|
---|
1473 | fatal (outside of main::) and an optional warning (inside of main::).
|
---|
1474 | The ability to detect whether a constant had been set with a given name has
|
---|
1475 | been added.
|
---|
1476 |
|
---|
1477 | See L<constant>.
|
---|
1478 |
|
---|
1479 | =item charnames
|
---|
1480 |
|
---|
1481 | This pragma implements the C<\N> string escape. See L<charnames>.
|
---|
1482 |
|
---|
1483 | =item Data::Dumper
|
---|
1484 |
|
---|
1485 | A C<Maxdepth> setting can be specified to avoid venturing
|
---|
1486 | too deeply into deep data structures. See L<Data::Dumper>.
|
---|
1487 |
|
---|
1488 | The XSUB implementation of Dump() is now automatically called if the
|
---|
1489 | C<Useqq> setting is not in use.
|
---|
1490 |
|
---|
1491 | Dumping C<qr//> objects works correctly.
|
---|
1492 |
|
---|
1493 | =item DB
|
---|
1494 |
|
---|
1495 | C<DB> is an experimental module that exposes a clean abstraction
|
---|
1496 | to Perl's debugging API.
|
---|
1497 |
|
---|
1498 | =item DB_File
|
---|
1499 |
|
---|
1500 | DB_File can now be built with Berkeley DB versions 1, 2 or 3.
|
---|
1501 | See C<ext/DB_File/Changes>.
|
---|
1502 |
|
---|
1503 | =item Devel::DProf
|
---|
1504 |
|
---|
1505 | Devel::DProf, a Perl source code profiler has been added. See
|
---|
1506 | L<Devel::DProf> and L<dprofpp>.
|
---|
1507 |
|
---|
1508 | =item Devel::Peek
|
---|
1509 |
|
---|
1510 | The Devel::Peek module provides access to the internal representation
|
---|
1511 | of Perl variables and data. It is a data debugging tool for the XS programmer.
|
---|
1512 |
|
---|
1513 | =item Dumpvalue
|
---|
1514 |
|
---|
1515 | The Dumpvalue module provides screen dumps of Perl data.
|
---|
1516 |
|
---|
1517 | =item DynaLoader
|
---|
1518 |
|
---|
1519 | DynaLoader now supports a dl_unload_file() function on platforms that
|
---|
1520 | support unloading shared objects using dlclose().
|
---|
1521 |
|
---|
1522 | Perl can also optionally arrange to unload all extension shared objects
|
---|
1523 | loaded by Perl. To enable this, build Perl with the Configure option
|
---|
1524 | C<-Accflags=-DDL_UNLOAD_ALL_AT_EXIT>. (This maybe useful if you are
|
---|
1525 | using Apache with mod_perl.)
|
---|
1526 |
|
---|
1527 | =item English
|
---|
1528 |
|
---|
1529 | $PERL_VERSION now stands for C<$^V> (a string value) rather than for C<$]>
|
---|
1530 | (a numeric value).
|
---|
1531 |
|
---|
1532 | =item Env
|
---|
1533 |
|
---|
1534 | Env now supports accessing environment variables like PATH as array
|
---|
1535 | variables.
|
---|
1536 |
|
---|
1537 | =item Fcntl
|
---|
1538 |
|
---|
1539 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
|
---|
1540 | large file (more than 4GB) access (NOTE: the O_LARGEFILE is
|
---|
1541 | automatically added to sysopen() flags if large file support has been
|
---|
1542 | configured, as is the default), Free/Net/OpenBSD locking behaviour
|
---|
1543 | flags F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the combined
|
---|
1544 | mask of O_RDONLY, O_WRONLY, and O_RDWR. The seek()/sysseek()
|
---|
1545 | constants SEEK_SET, SEEK_CUR, and SEEK_END are available via the
|
---|
1546 | C<:seek> tag. The chmod()/stat() S_IF* constants and S_IS* functions
|
---|
1547 | are available via the C<:mode> tag.
|
---|
1548 |
|
---|
1549 | =item File::Compare
|
---|
1550 |
|
---|
1551 | A compare_text() function has been added, which allows custom
|
---|
1552 | comparison functions. See L<File::Compare>.
|
---|
1553 |
|
---|
1554 | =item File::Find
|
---|
1555 |
|
---|
1556 | File::Find now works correctly when the wanted() function is either
|
---|
1557 | autoloaded or is a symbolic reference.
|
---|
1558 |
|
---|
1559 | A bug that caused File::Find to lose track of the working directory
|
---|
1560 | when pruning top-level directories has been fixed.
|
---|
1561 |
|
---|
1562 | File::Find now also supports several other options to control its
|
---|
1563 | behavior. It can follow symbolic links if the C<follow> option is
|
---|
1564 | specified. Enabling the C<no_chdir> option will make File::Find skip
|
---|
1565 | changing the current directory when walking directories. The C<untaint>
|
---|
1566 | flag can be useful when running with taint checks enabled.
|
---|
1567 |
|
---|
1568 | See L<File::Find>.
|
---|
1569 |
|
---|
1570 | =item File::Glob
|
---|
1571 |
|
---|
1572 | This extension implements BSD-style file globbing. By default,
|
---|
1573 | it will also be used for the internal implementation of the glob()
|
---|
1574 | operator. See L<File::Glob>.
|
---|
1575 |
|
---|
1576 | =item File::Spec
|
---|
1577 |
|
---|
1578 | New methods have been added to the File::Spec module: devnull() returns
|
---|
1579 | the name of the null device (/dev/null on Unix) and tmpdir() the name of
|
---|
1580 | the temp directory (normally /tmp on Unix). There are now also methods
|
---|
1581 | to convert between absolute and relative filenames: abs2rel() and
|
---|
1582 | rel2abs(). For compatibility with operating systems that specify volume
|
---|
1583 | names in file paths, the splitpath(), splitdir(), and catdir() methods
|
---|
1584 | have been added.
|
---|
1585 |
|
---|
1586 | =item File::Spec::Functions
|
---|
1587 |
|
---|
1588 | The new File::Spec::Functions modules provides a function interface
|
---|
1589 | to the File::Spec module. Allows shorthand
|
---|
1590 |
|
---|
1591 | $fullname = catfile($dir1, $dir2, $file);
|
---|
1592 |
|
---|
1593 | instead of
|
---|
1594 |
|
---|
1595 | $fullname = File::Spec->catfile($dir1, $dir2, $file);
|
---|
1596 |
|
---|
1597 | =item Getopt::Long
|
---|
1598 |
|
---|
1599 | Getopt::Long licensing has changed to allow the Perl Artistic License
|
---|
1600 | as well as the GPL. It used to be GPL only, which got in the way of
|
---|
1601 | non-GPL applications that wanted to use Getopt::Long.
|
---|
1602 |
|
---|
1603 | Getopt::Long encourages the use of Pod::Usage to produce help
|
---|
1604 | messages. For example:
|
---|
1605 |
|
---|
1606 | use Getopt::Long;
|
---|
1607 | use Pod::Usage;
|
---|
1608 | my $man = 0;
|
---|
1609 | my $help = 0;
|
---|
1610 | GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
|
---|
1611 | pod2usage(1) if $help;
|
---|
1612 | pod2usage(-exitstatus => 0, -verbose => 2) if $man;
|
---|
1613 |
|
---|
1614 | __END__
|
---|
1615 |
|
---|
1616 | =head1 NAME
|
---|
1617 |
|
---|
1618 | sample - Using Getopt::Long and Pod::Usage
|
---|
1619 |
|
---|
1620 | =head1 SYNOPSIS
|
---|
1621 |
|
---|
1622 | sample [options] [file ...]
|
---|
1623 |
|
---|
1624 | Options:
|
---|
1625 | -help brief help message
|
---|
1626 | -man full documentation
|
---|
1627 |
|
---|
1628 | =head1 OPTIONS
|
---|
1629 |
|
---|
1630 | =over 8
|
---|
1631 |
|
---|
1632 | =item B<-help>
|
---|
1633 |
|
---|
1634 | Print a brief help message and exits.
|
---|
1635 |
|
---|
1636 | =item B<-man>
|
---|
1637 |
|
---|
1638 | Prints the manual page and exits.
|
---|
1639 |
|
---|
1640 | =back
|
---|
1641 |
|
---|
1642 | =head1 DESCRIPTION
|
---|
1643 |
|
---|
1644 | B<This program> will read the given input file(s) and do something
|
---|
1645 | useful with the contents thereof.
|
---|
1646 |
|
---|
1647 | =cut
|
---|
1648 |
|
---|
1649 | See L<Pod::Usage> for details.
|
---|
1650 |
|
---|
1651 | A bug that prevented the non-option call-back <> from being
|
---|
1652 | specified as the first argument has been fixed.
|
---|
1653 |
|
---|
1654 | To specify the characters < and > as option starters, use ><. Note,
|
---|
1655 | however, that changing option starters is strongly deprecated.
|
---|
1656 |
|
---|
1657 | =item IO
|
---|
1658 |
|
---|
1659 | write() and syswrite() will now accept a single-argument
|
---|
1660 | form of the call, for consistency with Perl's syswrite().
|
---|
1661 |
|
---|
1662 | You can now create a TCP-based IO::Socket::INET without forcing
|
---|
1663 | a connect attempt. This allows you to configure its options
|
---|
1664 | (like making it non-blocking) and then call connect() manually.
|
---|
1665 |
|
---|
1666 | A bug that prevented the IO::Socket::protocol() accessor
|
---|
1667 | from ever returning the correct value has been corrected.
|
---|
1668 |
|
---|
1669 | IO::Socket::connect now uses non-blocking IO instead of alarm()
|
---|
1670 | to do connect timeouts.
|
---|
1671 |
|
---|
1672 | IO::Socket::accept now uses select() instead of alarm() for doing
|
---|
1673 | timeouts.
|
---|
1674 |
|
---|
1675 | IO::Socket::INET->new now sets $! correctly on failure. $@ is
|
---|
1676 | still set for backwards compatibility.
|
---|
1677 |
|
---|
1678 | =item JPL
|
---|
1679 |
|
---|
1680 | Java Perl Lingo is now distributed with Perl. See jpl/README
|
---|
1681 | for more information.
|
---|
1682 |
|
---|
1683 | =item lib
|
---|
1684 |
|
---|
1685 | C<use lib> now weeds out any trailing duplicate entries.
|
---|
1686 | C<no lib> removes all named entries.
|
---|
1687 |
|
---|
1688 | =item Math::BigInt
|
---|
1689 |
|
---|
1690 | The bitwise operations C<<< << >>>, C<<< >> >>>, C<&>, C<|>,
|
---|
1691 | and C<~> are now supported on bigints.
|
---|
1692 |
|
---|
1693 | =item Math::Complex
|
---|
1694 |
|
---|
1695 | The accessor methods Re, Im, arg, abs, rho, and theta can now also
|
---|
1696 | act as mutators (accessor $z->Re(), mutator $z->Re(3)).
|
---|
1697 |
|
---|
1698 | The class method C<display_format> and the corresponding object method
|
---|
1699 | C<display_format>, in addition to accepting just one argument, now can
|
---|
1700 | also accept a parameter hash. Recognized keys of a parameter hash are
|
---|
1701 | C<"style">, which corresponds to the old one parameter case, and two
|
---|
1702 | new parameters: C<"format">, which is a printf()-style format string
|
---|
1703 | (defaults usually to C<"%.15g">, you can revert to the default by
|
---|
1704 | setting the format string to C<undef>) used for both parts of a
|
---|
1705 | complex number, and C<"polar_pretty_print"> (defaults to true),
|
---|
1706 | which controls whether an attempt is made to try to recognize small
|
---|
1707 | multiples and rationals of pi (2pi, pi/2) at the argument (angle) of a
|
---|
1708 | polar complex number.
|
---|
1709 |
|
---|
1710 | The potentially disruptive change is that in list context both methods
|
---|
1711 | now I<return the parameter hash>, instead of only the value of the
|
---|
1712 | C<"style"> parameter.
|
---|
1713 |
|
---|
1714 | =item Math::Trig
|
---|
1715 |
|
---|
1716 | A little bit of radial trigonometry (cylindrical and spherical),
|
---|
1717 | radial coordinate conversions, and the great circle distance were added.
|
---|
1718 |
|
---|
1719 | =item Pod::Parser, Pod::InputObjects
|
---|
1720 |
|
---|
1721 | Pod::Parser is a base class for parsing and selecting sections of
|
---|
1722 | pod documentation from an input stream. This module takes care of
|
---|
1723 | identifying pod paragraphs and commands in the input and hands off the
|
---|
1724 | parsed paragraphs and commands to user-defined methods which are free
|
---|
1725 | to interpret or translate them as they see fit.
|
---|
1726 |
|
---|
1727 | Pod::InputObjects defines some input objects needed by Pod::Parser, and
|
---|
1728 | for advanced users of Pod::Parser that need more about a command besides
|
---|
1729 | its name and text.
|
---|
1730 |
|
---|
1731 | As of release 5.6.0 of Perl, Pod::Parser is now the officially sanctioned
|
---|
1732 | "base parser code" recommended for use by all pod2xxx translators.
|
---|
1733 | Pod::Text (pod2text) and Pod::Man (pod2man) have already been converted
|
---|
1734 | to use Pod::Parser and efforts to convert Pod::HTML (pod2html) are already
|
---|
1735 | underway. For any questions or comments about pod parsing and translating
|
---|
1736 | issues and utilities, please use the [email protected] mailing list.
|
---|
1737 |
|
---|
1738 | For further information, please see L<Pod::Parser> and L<Pod::InputObjects>.
|
---|
1739 |
|
---|
1740 | =item Pod::Checker, podchecker
|
---|
1741 |
|
---|
1742 | This utility checks pod files for correct syntax, according to
|
---|
1743 | L<perlpod>. Obvious errors are flagged as such, while warnings are
|
---|
1744 | printed for mistakes that can be handled gracefully. The checklist is
|
---|
1745 | not complete yet. See L<Pod::Checker>.
|
---|
1746 |
|
---|
1747 | =item Pod::ParseUtils, Pod::Find
|
---|
1748 |
|
---|
1749 | These modules provide a set of gizmos that are useful mainly for pod
|
---|
1750 | translators. L<Pod::Find|Pod::Find> traverses directory structures and
|
---|
1751 | returns found pod files, along with their canonical names (like
|
---|
1752 | C<File::Spec::Unix>). L<Pod::ParseUtils|Pod::ParseUtils> contains
|
---|
1753 | B<Pod::List> (useful for storing pod list information), B<Pod::Hyperlink>
|
---|
1754 | (for parsing the contents of C<LE<lt>E<gt>> sequences) and B<Pod::Cache>
|
---|
1755 | (for caching information about pod files, e.g., link nodes).
|
---|
1756 |
|
---|
1757 | =item Pod::Select, podselect
|
---|
1758 |
|
---|
1759 | Pod::Select is a subclass of Pod::Parser which provides a function
|
---|
1760 | named "podselect()" to filter out user-specified sections of raw pod
|
---|
1761 | documentation from an input stream. podselect is a script that provides
|
---|
1762 | access to Pod::Select from other scripts to be used as a filter.
|
---|
1763 | See L<Pod::Select>.
|
---|
1764 |
|
---|
1765 | =item Pod::Usage, pod2usage
|
---|
1766 |
|
---|
1767 | Pod::Usage provides the function "pod2usage()" to print usage messages for
|
---|
1768 | a Perl script based on its embedded pod documentation. The pod2usage()
|
---|
1769 | function is generally useful to all script authors since it lets them
|
---|
1770 | write and maintain a single source (the pods) for documentation, thus
|
---|
1771 | removing the need to create and maintain redundant usage message text
|
---|
1772 | consisting of information already in the pods.
|
---|
1773 |
|
---|
1774 | There is also a pod2usage script which can be used from other kinds of
|
---|
1775 | scripts to print usage messages from pods (even for non-Perl scripts
|
---|
1776 | with pods embedded in comments).
|
---|
1777 |
|
---|
1778 | For details and examples, please see L<Pod::Usage>.
|
---|
1779 |
|
---|
1780 | =item Pod::Text and Pod::Man
|
---|
1781 |
|
---|
1782 | Pod::Text has been rewritten to use Pod::Parser. While pod2text() is
|
---|
1783 | still available for backwards compatibility, the module now has a new
|
---|
1784 | preferred interface. See L<Pod::Text> for the details. The new Pod::Text
|
---|
1785 | module is easily subclassed for tweaks to the output, and two such
|
---|
1786 | subclasses (Pod::Text::Termcap for man-page-style bold and underlining
|
---|
1787 | using termcap information, and Pod::Text::Color for markup with ANSI color
|
---|
1788 | sequences) are now standard.
|
---|
1789 |
|
---|
1790 | pod2man has been turned into a module, Pod::Man, which also uses
|
---|
1791 | Pod::Parser. In the process, several outstanding bugs related to quotes
|
---|
1792 | in section headers, quoting of code escapes, and nested lists have been
|
---|
1793 | fixed. pod2man is now a wrapper script around this module.
|
---|
1794 |
|
---|
1795 | =item SDBM_File
|
---|
1796 |
|
---|
1797 | An EXISTS method has been added to this module (and sdbm_exists() has
|
---|
1798 | been added to the underlying sdbm library), so one can now call exists
|
---|
1799 | on an SDBM_File tied hash and get the correct result, rather than a
|
---|
1800 | runtime error.
|
---|
1801 |
|
---|
1802 | A bug that may have caused data loss when more than one disk block
|
---|
1803 | happens to be read from the database in a single FETCH() has been
|
---|
1804 | fixed.
|
---|
1805 |
|
---|
1806 | =item Sys::Syslog
|
---|
1807 |
|
---|
1808 | Sys::Syslog now uses XSUBs to access facilities from syslog.h so it
|
---|
1809 | no longer requires syslog.ph to exist.
|
---|
1810 |
|
---|
1811 | =item Sys::Hostname
|
---|
1812 |
|
---|
1813 | Sys::Hostname now uses XSUBs to call the C library's gethostname() or
|
---|
1814 | uname() if they exist.
|
---|
1815 |
|
---|
1816 | =item Term::ANSIColor
|
---|
1817 |
|
---|
1818 | Term::ANSIColor is a very simple module to provide easy and readable
|
---|
1819 | access to the ANSI color and highlighting escape sequences, supported by
|
---|
1820 | most ANSI terminal emulators. It is now included standard.
|
---|
1821 |
|
---|
1822 | =item Time::Local
|
---|
1823 |
|
---|
1824 | The timelocal() and timegm() functions used to silently return bogus
|
---|
1825 | results when the date fell outside the machine's integer range. They
|
---|
1826 | now consistently croak() if the date falls in an unsupported range.
|
---|
1827 |
|
---|
1828 | =item Win32
|
---|
1829 |
|
---|
1830 | The error return value in list context has been changed for all functions
|
---|
1831 | that return a list of values. Previously these functions returned a list
|
---|
1832 | with a single element C<undef> if an error occurred. Now these functions
|
---|
1833 | return the empty list in these situations. This applies to the following
|
---|
1834 | functions:
|
---|
1835 |
|
---|
1836 | Win32::FsType
|
---|
1837 | Win32::GetOSVersion
|
---|
1838 |
|
---|
1839 | The remaining functions are unchanged and continue to return C<undef> on
|
---|
1840 | error even in list context.
|
---|
1841 |
|
---|
1842 | The Win32::SetLastError(ERROR) function has been added as a complement
|
---|
1843 | to the Win32::GetLastError() function.
|
---|
1844 |
|
---|
1845 | The new Win32::GetFullPathName(FILENAME) returns the full absolute
|
---|
1846 | pathname for FILENAME in scalar context. In list context it returns
|
---|
1847 | a two-element list containing the fully qualified directory name and
|
---|
1848 | the filename. See L<Win32>.
|
---|
1849 |
|
---|
1850 | =item XSLoader
|
---|
1851 |
|
---|
1852 | The XSLoader extension is a simpler alternative to DynaLoader.
|
---|
1853 | See L<XSLoader>.
|
---|
1854 |
|
---|
1855 | =item DBM Filters
|
---|
1856 |
|
---|
1857 | A new feature called "DBM Filters" has been added to all the
|
---|
1858 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File.
|
---|
1859 | DBM Filters add four new methods to each DBM module:
|
---|
1860 |
|
---|
1861 | filter_store_key
|
---|
1862 | filter_store_value
|
---|
1863 | filter_fetch_key
|
---|
1864 | filter_fetch_value
|
---|
1865 |
|
---|
1866 | These can be used to filter key-value pairs before the pairs are
|
---|
1867 | written to the database or just after they are read from the database.
|
---|
1868 | See L<perldbmfilter> for further information.
|
---|
1869 |
|
---|
1870 | =back
|
---|
1871 |
|
---|
1872 | =head2 Pragmata
|
---|
1873 |
|
---|
1874 | C<use attrs> is now obsolete, and is only provided for
|
---|
1875 | backward-compatibility. It's been replaced by the C<sub : attributes>
|
---|
1876 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>.
|
---|
1877 |
|
---|
1878 | Lexical warnings pragma, C<use warnings;>, to control optional warnings.
|
---|
1879 | See L<perllexwarn>.
|
---|
1880 |
|
---|
1881 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w>
|
---|
1882 | ...). Currently only one subpragma implemented, "use filetest
|
---|
1883 | 'access';", that uses access(2) or equivalent to check permissions
|
---|
1884 | instead of using stat(2) as usual. This matters in filesystems
|
---|
1885 | where there are ACLs (access control lists): the stat(2) might lie,
|
---|
1886 | but access(2) knows better.
|
---|
1887 |
|
---|
1888 | The C<open> pragma can be used to specify default disciplines for
|
---|
1889 | handle constructors (e.g. open()) and for qx//. The two
|
---|
1890 | pseudo-disciplines C<:raw> and C<:crlf> are currently supported on
|
---|
1891 | DOS-derivative platforms (i.e. where binmode is not a no-op).
|
---|
1892 | See also L</"binmode() can be used to set :crlf and :raw modes">.
|
---|
1893 |
|
---|
1894 | =head1 Utility Changes
|
---|
1895 |
|
---|
1896 | =head2 dprofpp
|
---|
1897 |
|
---|
1898 | C<dprofpp> is used to display profile data generated using C<Devel::DProf>.
|
---|
1899 | See L<dprofpp>.
|
---|
1900 |
|
---|
1901 | =head2 find2perl
|
---|
1902 |
|
---|
1903 | The C<find2perl> utility now uses the enhanced features of the File::Find
|
---|
1904 | module. The -depth and -follow options are supported. Pod documentation
|
---|
1905 | is also included in the script.
|
---|
1906 |
|
---|
1907 | =head2 h2xs
|
---|
1908 |
|
---|
1909 | The C<h2xs> tool can now work in conjunction with C<C::Scan> (available
|
---|
1910 | from CPAN) to automatically parse real-life header files. The C<-M>,
|
---|
1911 | C<-a>, C<-k>, and C<-o> options are new.
|
---|
1912 |
|
---|
1913 | =head2 perlcc
|
---|
1914 |
|
---|
1915 | C<perlcc> now supports the C and Bytecode backends. By default,
|
---|
1916 | it generates output from the simple C backend rather than the
|
---|
1917 | optimized C backend.
|
---|
1918 |
|
---|
1919 | Support for non-Unix platforms has been improved.
|
---|
1920 |
|
---|
1921 | =head2 perldoc
|
---|
1922 |
|
---|
1923 | C<perldoc> has been reworked to avoid possible security holes.
|
---|
1924 | It will not by default let itself be run as the superuser, but you
|
---|
1925 | may still use the B<-U> switch to try to make it drop privileges
|
---|
1926 | first.
|
---|
1927 |
|
---|
1928 | =head2 The Perl Debugger
|
---|
1929 |
|
---|
1930 | Many bug fixes and enhancements were added to F<perl5db.pl>, the
|
---|
1931 | Perl debugger. The help documentation was rearranged. New commands
|
---|
1932 | include C<< < ? >>, C<< > ? >>, and C<< { ? >> to list out current
|
---|
1933 | actions, C<man I<docpage>> to run your doc viewer on some perl
|
---|
1934 | docset, and support for quoted options. The help information was
|
---|
1935 | rearranged, and should be viewable once again if you're using B<less>
|
---|
1936 | as your pager. A serious security hole was plugged--you should
|
---|
1937 | immediately remove all older versions of the Perl debugger as
|
---|
1938 | installed in previous releases, all the way back to perl3, from
|
---|
1939 | your system to avoid being bitten by this.
|
---|
1940 |
|
---|
1941 | =head1 Improved Documentation
|
---|
1942 |
|
---|
1943 | Many of the platform-specific README files are now part of the perl
|
---|
1944 | installation. See L<perl> for the complete list.
|
---|
1945 |
|
---|
1946 | =over 4
|
---|
1947 |
|
---|
1948 | =item perlapi.pod
|
---|
1949 |
|
---|
1950 | The official list of public Perl API functions.
|
---|
1951 |
|
---|
1952 | =item perlboot.pod
|
---|
1953 |
|
---|
1954 | A tutorial for beginners on object-oriented Perl.
|
---|
1955 |
|
---|
1956 | =item perlcompile.pod
|
---|
1957 |
|
---|
1958 | An introduction to using the Perl Compiler suite.
|
---|
1959 |
|
---|
1960 | =item perldbmfilter.pod
|
---|
1961 |
|
---|
1962 | A howto document on using the DBM filter facility.
|
---|
1963 |
|
---|
1964 | =item perldebug.pod
|
---|
1965 |
|
---|
1966 | All material unrelated to running the Perl debugger, plus all
|
---|
1967 | low-level guts-like details that risked crushing the casual user
|
---|
1968 | of the debugger, have been relocated from the old manpage to the
|
---|
1969 | next entry below.
|
---|
1970 |
|
---|
1971 | =item perldebguts.pod
|
---|
1972 |
|
---|
1973 | This new manpage contains excessively low-level material not related
|
---|
1974 | to the Perl debugger, but slightly related to debugging Perl itself.
|
---|
1975 | It also contains some arcane internal details of how the debugging
|
---|
1976 | process works that may only be of interest to developers of Perl
|
---|
1977 | debuggers.
|
---|
1978 |
|
---|
1979 | =item perlfork.pod
|
---|
1980 |
|
---|
1981 | Notes on the fork() emulation currently available for the Windows platform.
|
---|
1982 |
|
---|
1983 | =item perlfilter.pod
|
---|
1984 |
|
---|
1985 | An introduction to writing Perl source filters.
|
---|
1986 |
|
---|
1987 | =item perlhack.pod
|
---|
1988 |
|
---|
1989 | Some guidelines for hacking the Perl source code.
|
---|
1990 |
|
---|
1991 | =item perlintern.pod
|
---|
1992 |
|
---|
1993 | A list of internal functions in the Perl source code.
|
---|
1994 | (List is currently empty.)
|
---|
1995 |
|
---|
1996 | =item perllexwarn.pod
|
---|
1997 |
|
---|
1998 | Introduction and reference information about lexically scoped
|
---|
1999 | warning categories.
|
---|
2000 |
|
---|
2001 | =item perlnumber.pod
|
---|
2002 |
|
---|
2003 | Detailed information about numbers as they are represented in Perl.
|
---|
2004 |
|
---|
2005 | =item perlopentut.pod
|
---|
2006 |
|
---|
2007 | A tutorial on using open() effectively.
|
---|
2008 |
|
---|
2009 | =item perlreftut.pod
|
---|
2010 |
|
---|
2011 | A tutorial that introduces the essentials of references.
|
---|
2012 |
|
---|
2013 | =item perltootc.pod
|
---|
2014 |
|
---|
2015 | A tutorial on managing class data for object modules.
|
---|
2016 |
|
---|
2017 | =item perltodo.pod
|
---|
2018 |
|
---|
2019 | Discussion of the most often wanted features that may someday be
|
---|
2020 | supported in Perl.
|
---|
2021 |
|
---|
2022 | =item perlunicode.pod
|
---|
2023 |
|
---|
2024 | An introduction to Unicode support features in Perl.
|
---|
2025 |
|
---|
2026 | =back
|
---|
2027 |
|
---|
2028 | =head1 Performance enhancements
|
---|
2029 |
|
---|
2030 | =head2 Simple sort() using { $a <=> $b } and the like are optimized
|
---|
2031 |
|
---|
2032 | Many common sort() operations using a simple inlined block are now
|
---|
2033 | optimized for faster performance.
|
---|
2034 |
|
---|
2035 | =head2 Optimized assignments to lexical variables
|
---|
2036 |
|
---|
2037 | Certain operations in the RHS of assignment statements have been
|
---|
2038 | optimized to directly set the lexical variable on the LHS,
|
---|
2039 | eliminating redundant copying overheads.
|
---|
2040 |
|
---|
2041 | =head2 Faster subroutine calls
|
---|
2042 |
|
---|
2043 | Minor changes in how subroutine calls are handled internally
|
---|
2044 | provide marginal improvements in performance.
|
---|
2045 |
|
---|
2046 | =head2 delete(), each(), values() and hash iteration are faster
|
---|
2047 |
|
---|
2048 | The hash values returned by delete(), each(), values() and hashes in a
|
---|
2049 | list context are the actual values in the hash, instead of copies.
|
---|
2050 | This results in significantly better performance, because it eliminates
|
---|
2051 | needless copying in most situations.
|
---|
2052 |
|
---|
2053 | =head1 Installation and Configuration Improvements
|
---|
2054 |
|
---|
2055 | =head2 -Dusethreads means something different
|
---|
2056 |
|
---|
2057 | The -Dusethreads flag now enables the experimental interpreter-based thread
|
---|
2058 | support by default. To get the flavor of experimental threads that was in
|
---|
2059 | 5.005 instead, you need to run Configure with "-Dusethreads -Duse5005threads".
|
---|
2060 |
|
---|
2061 | As of v5.6.0, interpreter-threads support is still lacking a way to
|
---|
2062 | create new threads from Perl (i.e., C<use Thread;> will not work with
|
---|
2063 | interpreter threads). C<use Thread;> continues to be available when you
|
---|
2064 | specify the -Duse5005threads option to Configure, bugs and all.
|
---|
2065 |
|
---|
2066 | NOTE: Support for threads continues to be an experimental feature.
|
---|
2067 | Interfaces and implementation are subject to sudden and drastic changes.
|
---|
2068 |
|
---|
2069 | =head2 New Configure flags
|
---|
2070 |
|
---|
2071 | The following new flags may be enabled on the Configure command line
|
---|
2072 | by running Configure with C<-Dflag>.
|
---|
2073 |
|
---|
2074 | usemultiplicity
|
---|
2075 | usethreads useithreads (new interpreter threads: no Perl API yet)
|
---|
2076 | usethreads use5005threads (threads as they were in 5.005)
|
---|
2077 |
|
---|
2078 | use64bitint (equal to now deprecated 'use64bits')
|
---|
2079 | use64bitall
|
---|
2080 |
|
---|
2081 | uselongdouble
|
---|
2082 | usemorebits
|
---|
2083 | uselargefiles
|
---|
2084 | usesocks (only SOCKS v5 supported)
|
---|
2085 |
|
---|
2086 | =head2 Threadedness and 64-bitness now more daring
|
---|
2087 |
|
---|
2088 | The Configure options enabling the use of threads and the use of
|
---|
2089 | 64-bitness are now more daring in the sense that they no more have an
|
---|
2090 | explicit list of operating systems of known threads/64-bit
|
---|
2091 | capabilities. In other words: if your operating system has the
|
---|
2092 | necessary APIs and datatypes, you should be able just to go ahead and
|
---|
2093 | use them, for threads by Configure -Dusethreads, and for 64 bits
|
---|
2094 | either explicitly by Configure -Duse64bitint or implicitly if your
|
---|
2095 | system has 64-bit wide datatypes. See also L<"64-bit support">.
|
---|
2096 |
|
---|
2097 | =head2 Long Doubles
|
---|
2098 |
|
---|
2099 | Some platforms have "long doubles", floating point numbers of even
|
---|
2100 | larger range than ordinary "doubles". To enable using long doubles for
|
---|
2101 | Perl's scalars, use -Duselongdouble.
|
---|
2102 |
|
---|
2103 | =head2 -Dusemorebits
|
---|
2104 |
|
---|
2105 | You can enable both -Duse64bitint and -Duselongdouble with -Dusemorebits.
|
---|
2106 | See also L<"64-bit support">.
|
---|
2107 |
|
---|
2108 | =head2 -Duselargefiles
|
---|
2109 |
|
---|
2110 | Some platforms support system APIs that are capable of handling large files
|
---|
2111 | (typically, files larger than two gigabytes). Perl will try to use these
|
---|
2112 | APIs if you ask for -Duselargefiles.
|
---|
2113 |
|
---|
2114 | See L<"Large file support"> for more information.
|
---|
2115 |
|
---|
2116 | =head2 installusrbinperl
|
---|
2117 |
|
---|
2118 | You can use "Configure -Uinstallusrbinperl" which causes installperl
|
---|
2119 | to skip installing perl also as /usr/bin/perl. This is useful if you
|
---|
2120 | prefer not to modify /usr/bin for some reason or another but harmful
|
---|
2121 | because many scripts assume to find Perl in /usr/bin/perl.
|
---|
2122 |
|
---|
2123 | =head2 SOCKS support
|
---|
2124 |
|
---|
2125 | You can use "Configure -Dusesocks" which causes Perl to probe
|
---|
2126 | for the SOCKS proxy protocol library (v5, not v4). For more information
|
---|
2127 | on SOCKS, see:
|
---|
2128 |
|
---|
2129 | http://www.socks.nec.com/
|
---|
2130 |
|
---|
2131 | =head2 C<-A> flag
|
---|
2132 |
|
---|
2133 | You can "post-edit" the Configure variables using the Configure C<-A>
|
---|
2134 | switch. The editing happens immediately after the platform specific
|
---|
2135 | hints files have been processed but before the actual configuration
|
---|
2136 | process starts. Run C<Configure -h> to find out the full C<-A> syntax.
|
---|
2137 |
|
---|
2138 | =head2 Enhanced Installation Directories
|
---|
2139 |
|
---|
2140 | The installation structure has been enriched to improve the support
|
---|
2141 | for maintaining multiple versions of perl, to provide locations for
|
---|
2142 | vendor-supplied modules, scripts, and manpages, and to ease maintenance
|
---|
2143 | of locally-added modules, scripts, and manpages. See the section on
|
---|
2144 | Installation Directories in the INSTALL file for complete details.
|
---|
2145 | For most users building and installing from source, the defaults should
|
---|
2146 | be fine.
|
---|
2147 |
|
---|
2148 | If you previously used C<Configure -Dsitelib> or C<-Dsitearch> to set
|
---|
2149 | special values for library directories, you might wish to consider using
|
---|
2150 | the new C<-Dsiteprefix> setting instead. Also, if you wish to re-use a
|
---|
2151 | config.sh file from an earlier version of perl, you should be sure to
|
---|
2152 | check that Configure makes sensible choices for the new directories.
|
---|
2153 | See INSTALL for complete details.
|
---|
2154 |
|
---|
2155 | =head2 gcc automatically tried if 'cc' does not seem to be working
|
---|
2156 |
|
---|
2157 | In many platforms the vendor-supplied 'cc' is too stripped-down to
|
---|
2158 | build Perl (basically, the 'cc' doesn't do ANSI C). If this seems
|
---|
2159 | to be the case and the 'cc' does not seem to be the GNU C compiler
|
---|
2160 | 'gcc', an automatic attempt is made to find and use 'gcc' instead.
|
---|
2161 |
|
---|
2162 | =head1 Platform specific changes
|
---|
2163 |
|
---|
2164 | =head2 Supported platforms
|
---|
2165 |
|
---|
2166 | =over 4
|
---|
2167 |
|
---|
2168 | =item *
|
---|
2169 |
|
---|
2170 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread
|
---|
2171 | extension.
|
---|
2172 |
|
---|
2173 | =item *
|
---|
2174 |
|
---|
2175 | GNU/Hurd is now supported.
|
---|
2176 |
|
---|
2177 | =item *
|
---|
2178 |
|
---|
2179 | Rhapsody/Darwin is now supported.
|
---|
2180 |
|
---|
2181 | =item *
|
---|
2182 |
|
---|
2183 | EPOC is now supported (on Psion 5).
|
---|
2184 |
|
---|
2185 | =item *
|
---|
2186 |
|
---|
2187 | The cygwin port (formerly cygwin32) has been greatly improved.
|
---|
2188 |
|
---|
2189 | =back
|
---|
2190 |
|
---|
2191 | =head2 DOS
|
---|
2192 |
|
---|
2193 | =over 4
|
---|
2194 |
|
---|
2195 | =item *
|
---|
2196 |
|
---|
2197 | Perl now works with djgpp 2.02 (and 2.03 alpha).
|
---|
2198 |
|
---|
2199 | =item *
|
---|
2200 |
|
---|
2201 | Environment variable names are not converted to uppercase any more.
|
---|
2202 |
|
---|
2203 | =item *
|
---|
2204 |
|
---|
2205 | Incorrect exit codes from backticks have been fixed.
|
---|
2206 |
|
---|
2207 | =item *
|
---|
2208 |
|
---|
2209 | This port continues to use its own builtin globbing (not File::Glob).
|
---|
2210 |
|
---|
2211 | =back
|
---|
2212 |
|
---|
2213 | =head2 OS390 (OpenEdition MVS)
|
---|
2214 |
|
---|
2215 | Support for this EBCDIC platform has not been renewed in this release.
|
---|
2216 | There are difficulties in reconciling Perl's standardization on UTF-8
|
---|
2217 | as its internal representation for characters with the EBCDIC character
|
---|
2218 | set, because the two are incompatible.
|
---|
2219 |
|
---|
2220 | It is unclear whether future versions will renew support for this
|
---|
2221 | platform, but the possibility exists.
|
---|
2222 |
|
---|
2223 | =head2 VMS
|
---|
2224 |
|
---|
2225 | Numerous revisions and extensions to configuration, build, testing, and
|
---|
2226 | installation process to accommodate core changes and VMS-specific options.
|
---|
2227 |
|
---|
2228 | Expand %ENV-handling code to allow runtime mapping to logical names,
|
---|
2229 | CLI symbols, and CRTL environ array.
|
---|
2230 |
|
---|
2231 | Extension of subprocess invocation code to accept filespecs as command
|
---|
2232 | "verbs".
|
---|
2233 |
|
---|
2234 | Add to Perl command line processing the ability to use default file types and
|
---|
2235 | to recognize Unix-style C<2E<gt>&1>.
|
---|
2236 |
|
---|
2237 | Expansion of File::Spec::VMS routines, and integration into ExtUtils::MM_VMS.
|
---|
2238 |
|
---|
2239 | Extension of ExtUtils::MM_VMS to handle complex extensions more flexibly.
|
---|
2240 |
|
---|
2241 | Barewords at start of Unix-syntax paths may be treated as text rather than
|
---|
2242 | only as logical names.
|
---|
2243 |
|
---|
2244 | Optional secure translation of several logical names used internally by Perl.
|
---|
2245 |
|
---|
2246 | Miscellaneous bugfixing and porting of new core code to VMS.
|
---|
2247 |
|
---|
2248 | Thanks are gladly extended to the many people who have contributed VMS
|
---|
2249 | patches, testing, and ideas.
|
---|
2250 |
|
---|
2251 | =head2 Win32
|
---|
2252 |
|
---|
2253 | Perl can now emulate fork() internally, using multiple interpreters running
|
---|
2254 | in different concurrent threads. This support must be enabled at build
|
---|
2255 | time. See L<perlfork> for detailed information.
|
---|
2256 |
|
---|
2257 | When given a pathname that consists only of a drivename, such as C<A:>,
|
---|
2258 | opendir() and stat() now use the current working directory for the drive
|
---|
2259 | rather than the drive root.
|
---|
2260 |
|
---|
2261 | The builtin XSUB functions in the Win32:: namespace are documented. See
|
---|
2262 | L<Win32>.
|
---|
2263 |
|
---|
2264 | $^X now contains the full path name of the running executable.
|
---|
2265 |
|
---|
2266 | A Win32::GetLongPathName() function is provided to complement
|
---|
2267 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>.
|
---|
2268 |
|
---|
2269 | POSIX::uname() is supported.
|
---|
2270 |
|
---|
2271 | system(1,...) now returns true process IDs rather than process
|
---|
2272 | handles. kill() accepts any real process id, rather than strictly
|
---|
2273 | return values from system(1,...).
|
---|
2274 |
|
---|
2275 | For better compatibility with Unix, C<kill(0, $pid)> can now be used to
|
---|
2276 | test whether a process exists.
|
---|
2277 |
|
---|
2278 | The C<Shell> module is supported.
|
---|
2279 |
|
---|
2280 | Better support for building Perl under command.com in Windows 95
|
---|
2281 | has been added.
|
---|
2282 |
|
---|
2283 | Scripts are read in binary mode by default to allow ByteLoader (and
|
---|
2284 | the filter mechanism in general) to work properly. For compatibility,
|
---|
2285 | the DATA filehandle will be set to text mode if a carriage return is
|
---|
2286 | detected at the end of the line containing the __END__ or __DATA__
|
---|
2287 | token; if not, the DATA filehandle will be left open in binary mode.
|
---|
2288 | Earlier versions always opened the DATA filehandle in text mode.
|
---|
2289 |
|
---|
2290 | The glob() operator is implemented via the C<File::Glob> extension,
|
---|
2291 | which supports glob syntax of the C shell. This increases the flexibility
|
---|
2292 | of the glob() operator, but there may be compatibility issues for
|
---|
2293 | programs that relied on the older globbing syntax. If you want to
|
---|
2294 | preserve compatibility with the older syntax, you might want to run
|
---|
2295 | perl with C<-MFile::DosGlob>. For details and compatibility information,
|
---|
2296 | see L<File::Glob>.
|
---|
2297 |
|
---|
2298 | =head1 Significant bug fixes
|
---|
2299 |
|
---|
2300 | =head2 <HANDLE> on empty files
|
---|
2301 |
|
---|
2302 | With C<$/> set to C<undef>, "slurping" an empty file returns a string of
|
---|
2303 | zero length (instead of C<undef>, as it used to) the first time the
|
---|
2304 | HANDLE is read after C<$/> is set to C<undef>. Further reads yield
|
---|
2305 | C<undef>.
|
---|
2306 |
|
---|
2307 | This means that the following will append "foo" to an empty file (it used
|
---|
2308 | to do nothing):
|
---|
2309 |
|
---|
2310 | perl -0777 -pi -e 's/^/foo/' empty_file
|
---|
2311 |
|
---|
2312 | The behaviour of:
|
---|
2313 |
|
---|
2314 | perl -pi -e 's/^/foo/' empty_file
|
---|
2315 |
|
---|
2316 | is unchanged (it continues to leave the file empty).
|
---|
2317 |
|
---|
2318 | =head2 C<eval '...'> improvements
|
---|
2319 |
|
---|
2320 | Line numbers (as reflected by caller() and most diagnostics) within
|
---|
2321 | C<eval '...'> were often incorrect where here documents were involved.
|
---|
2322 | This has been corrected.
|
---|
2323 |
|
---|
2324 | Lexical lookups for variables appearing in C<eval '...'> within
|
---|
2325 | functions that were themselves called within an C<eval '...'> were
|
---|
2326 | searching the wrong place for lexicals. The lexical search now
|
---|
2327 | correctly ends at the subroutine's block boundary.
|
---|
2328 |
|
---|
2329 | The use of C<return> within C<eval {...}> caused $@ not to be reset
|
---|
2330 | correctly when no exception occurred within the eval. This has
|
---|
2331 | been fixed.
|
---|
2332 |
|
---|
2333 | Parsing of here documents used to be flawed when they appeared as
|
---|
2334 | the replacement expression in C<eval 's/.../.../e'>. This has
|
---|
2335 | been fixed.
|
---|
2336 |
|
---|
2337 | =head2 All compilation errors are true errors
|
---|
2338 |
|
---|
2339 | Some "errors" encountered at compile time were by necessity
|
---|
2340 | generated as warnings followed by eventual termination of the
|
---|
2341 | program. This enabled more such errors to be reported in a
|
---|
2342 | single run, rather than causing a hard stop at the first error
|
---|
2343 | that was encountered.
|
---|
2344 |
|
---|
2345 | The mechanism for reporting such errors has been reimplemented
|
---|
2346 | to queue compile-time errors and report them at the end of the
|
---|
2347 | compilation as true errors rather than as warnings. This fixes
|
---|
2348 | cases where error messages leaked through in the form of warnings
|
---|
2349 | when code was compiled at run time using C<eval STRING>, and
|
---|
2350 | also allows such errors to be reliably trapped using C<eval "...">.
|
---|
2351 |
|
---|
2352 | =head2 Implicitly closed filehandles are safer
|
---|
2353 |
|
---|
2354 | Sometimes implicitly closed filehandles (as when they are localized,
|
---|
2355 | and Perl automatically closes them on exiting the scope) could
|
---|
2356 | inadvertently set $? or $!. This has been corrected.
|
---|
2357 |
|
---|
2358 |
|
---|
2359 | =head2 Behavior of list slices is more consistent
|
---|
2360 |
|
---|
2361 | When taking a slice of a literal list (as opposed to a slice of
|
---|
2362 | an array or hash), Perl used to return an empty list if the
|
---|
2363 | result happened to be composed of all undef values.
|
---|
2364 |
|
---|
2365 | The new behavior is to produce an empty list if (and only if)
|
---|
2366 | the original list was empty. Consider the following example:
|
---|
2367 |
|
---|
2368 | @a = (1,undef,undef,2)[2,1,2];
|
---|
2369 |
|
---|
2370 | The old behavior would have resulted in @a having no elements.
|
---|
2371 | The new behavior ensures it has three undefined elements.
|
---|
2372 |
|
---|
2373 | Note in particular that the behavior of slices of the following
|
---|
2374 | cases remains unchanged:
|
---|
2375 |
|
---|
2376 | @a = ()[1,2];
|
---|
2377 | @a = (getpwent)[7,0];
|
---|
2378 | @a = (anything_returning_empty_list())[2,1,2];
|
---|
2379 | @a = @b[2,1,2];
|
---|
2380 | @a = @c{'a','b','c'};
|
---|
2381 |
|
---|
2382 | See L<perldata>.
|
---|
2383 |
|
---|
2384 | =head2 C<(\$)> prototype and C<$foo{a}>
|
---|
2385 |
|
---|
2386 | A scalar reference prototype now correctly allows a hash or
|
---|
2387 | array element in that slot.
|
---|
2388 |
|
---|
2389 | =head2 C<goto &sub> and AUTOLOAD
|
---|
2390 |
|
---|
2391 | The C<goto &sub> construct works correctly when C<&sub> happens
|
---|
2392 | to be autoloaded.
|
---|
2393 |
|
---|
2394 | =head2 C<-bareword> allowed under C<use integer>
|
---|
2395 |
|
---|
2396 | The autoquoting of barewords preceded by C<-> did not work
|
---|
2397 | in prior versions when the C<integer> pragma was enabled.
|
---|
2398 | This has been fixed.
|
---|
2399 |
|
---|
2400 | =head2 Failures in DESTROY()
|
---|
2401 |
|
---|
2402 | When code in a destructor threw an exception, it went unnoticed
|
---|
2403 | in earlier versions of Perl, unless someone happened to be
|
---|
2404 | looking in $@ just after the point the destructor happened to
|
---|
2405 | run. Such failures are now visible as warnings when warnings are
|
---|
2406 | enabled.
|
---|
2407 |
|
---|
2408 | =head2 Locale bugs fixed
|
---|
2409 |
|
---|
2410 | printf() and sprintf() previously reset the numeric locale
|
---|
2411 | back to the default "C" locale. This has been fixed.
|
---|
2412 |
|
---|
2413 | Numbers formatted according to the local numeric locale
|
---|
2414 | (such as using a decimal comma instead of a decimal dot) caused
|
---|
2415 | "isn't numeric" warnings, even while the operations accessing
|
---|
2416 | those numbers produced correct results. These warnings have been
|
---|
2417 | discontinued.
|
---|
2418 |
|
---|
2419 | =head2 Memory leaks
|
---|
2420 |
|
---|
2421 | The C<eval 'return sub {...}'> construct could sometimes leak
|
---|
2422 | memory. This has been fixed.
|
---|
2423 |
|
---|
2424 | Operations that aren't filehandle constructors used to leak memory
|
---|
2425 | when used on invalid filehandles. This has been fixed.
|
---|
2426 |
|
---|
2427 | Constructs that modified C<@_> could fail to deallocate values
|
---|
2428 | in C<@_> and thus leak memory. This has been corrected.
|
---|
2429 |
|
---|
2430 | =head2 Spurious subroutine stubs after failed subroutine calls
|
---|
2431 |
|
---|
2432 | Perl could sometimes create empty subroutine stubs when a
|
---|
2433 | subroutine was not found in the package. Such cases stopped
|
---|
2434 | later method lookups from progressing into base packages.
|
---|
2435 | This has been corrected.
|
---|
2436 |
|
---|
2437 | =head2 Taint failures under C<-U>
|
---|
2438 |
|
---|
2439 | When running in unsafe mode, taint violations could sometimes
|
---|
2440 | cause silent failures. This has been fixed.
|
---|
2441 |
|
---|
2442 | =head2 END blocks and the C<-c> switch
|
---|
2443 |
|
---|
2444 | Prior versions used to run BEGIN B<and> END blocks when Perl was
|
---|
2445 | run in compile-only mode. Since this is typically not the expected
|
---|
2446 | behavior, END blocks are not executed anymore when the C<-c> switch
|
---|
2447 | is used, or if compilation fails.
|
---|
2448 |
|
---|
2449 | See L</"Support for CHECK blocks"> for how to run things when the compile
|
---|
2450 | phase ends.
|
---|
2451 |
|
---|
2452 | =head2 Potential to leak DATA filehandles
|
---|
2453 |
|
---|
2454 | Using the C<__DATA__> token creates an implicit filehandle to
|
---|
2455 | the file that contains the token. It is the program's
|
---|
2456 | responsibility to close it when it is done reading from it.
|
---|
2457 |
|
---|
2458 | This caveat is now better explained in the documentation.
|
---|
2459 | See L<perldata>.
|
---|
2460 |
|
---|
2461 | =head1 New or Changed Diagnostics
|
---|
2462 |
|
---|
2463 | =over 4
|
---|
2464 |
|
---|
2465 | =item "%s" variable %s masks earlier declaration in same %s
|
---|
2466 |
|
---|
2467 | (W misc) A "my" or "our" variable has been redeclared in the current scope or statement,
|
---|
2468 | effectively eliminating all access to the previous instance. This is almost
|
---|
2469 | always a typographical error. Note that the earlier variable will still exist
|
---|
2470 | until the end of the scope or until all closure referents to it are
|
---|
2471 | destroyed.
|
---|
2472 |
|
---|
2473 | =item "my sub" not yet implemented
|
---|
2474 |
|
---|
2475 | (F) Lexically scoped subroutines are not yet implemented. Don't try that
|
---|
2476 | yet.
|
---|
2477 |
|
---|
2478 | =item "our" variable %s redeclared
|
---|
2479 |
|
---|
2480 | (W misc) You seem to have already declared the same global once before in the
|
---|
2481 | current lexical scope.
|
---|
2482 |
|
---|
2483 | =item '!' allowed only after types %s
|
---|
2484 |
|
---|
2485 | (F) The '!' is allowed in pack() and unpack() only after certain types.
|
---|
2486 | See L<perlfunc/pack>.
|
---|
2487 |
|
---|
2488 | =item / cannot take a count
|
---|
2489 |
|
---|
2490 | (F) You had an unpack template indicating a counted-length string,
|
---|
2491 | but you have also specified an explicit size for the string.
|
---|
2492 | See L<perlfunc/pack>.
|
---|
2493 |
|
---|
2494 | =item / must be followed by a, A or Z
|
---|
2495 |
|
---|
2496 | (F) You had an unpack template indicating a counted-length string,
|
---|
2497 | which must be followed by one of the letters a, A or Z
|
---|
2498 | to indicate what sort of string is to be unpacked.
|
---|
2499 | See L<perlfunc/pack>.
|
---|
2500 |
|
---|
2501 | =item / must be followed by a*, A* or Z*
|
---|
2502 |
|
---|
2503 | (F) You had a pack template indicating a counted-length string,
|
---|
2504 | Currently the only things that can have their length counted are a*, A* or Z*.
|
---|
2505 | See L<perlfunc/pack>.
|
---|
2506 |
|
---|
2507 | =item / must follow a numeric type
|
---|
2508 |
|
---|
2509 | (F) You had an unpack template that contained a '#',
|
---|
2510 | but this did not follow some numeric unpack specification.
|
---|
2511 | See L<perlfunc/pack>.
|
---|
2512 |
|
---|
2513 | =item /%s/: Unrecognized escape \\%c passed through
|
---|
2514 |
|
---|
2515 | (W regexp) You used a backslash-character combination which is not recognized
|
---|
2516 | by Perl. This combination appears in an interpolated variable or a
|
---|
2517 | C<'>-delimited regular expression. The character was understood literally.
|
---|
2518 |
|
---|
2519 | =item /%s/: Unrecognized escape \\%c in character class passed through
|
---|
2520 |
|
---|
2521 | (W regexp) You used a backslash-character combination which is not recognized
|
---|
2522 | by Perl inside character classes. The character was understood literally.
|
---|
2523 |
|
---|
2524 | =item /%s/ should probably be written as "%s"
|
---|
2525 |
|
---|
2526 | (W syntax) You have used a pattern where Perl expected to find a string,
|
---|
2527 | as in the first argument to C<join>. Perl will treat the true
|
---|
2528 | or false result of matching the pattern against $_ as the string,
|
---|
2529 | which is probably not what you had in mind.
|
---|
2530 |
|
---|
2531 | =item %s() called too early to check prototype
|
---|
2532 |
|
---|
2533 | (W prototype) You've called a function that has a prototype before the parser saw a
|
---|
2534 | definition or declaration for it, and Perl could not check that the call
|
---|
2535 | conforms to the prototype. You need to either add an early prototype
|
---|
2536 | declaration for the subroutine in question, or move the subroutine
|
---|
2537 | definition ahead of the call to get proper prototype checking. Alternatively,
|
---|
2538 | if you are certain that you're calling the function correctly, you may put
|
---|
2539 | an ampersand before the name to avoid the warning. See L<perlsub>.
|
---|
2540 |
|
---|
2541 | =item %s argument is not a HASH or ARRAY element
|
---|
2542 |
|
---|
2543 | (F) The argument to exists() must be a hash or array element, such as:
|
---|
2544 |
|
---|
2545 | $foo{$bar}
|
---|
2546 | $ref->{"susie"}[12]
|
---|
2547 |
|
---|
2548 | =item %s argument is not a HASH or ARRAY element or slice
|
---|
2549 |
|
---|
2550 | (F) The argument to delete() must be either a hash or array element, such as:
|
---|
2551 |
|
---|
2552 | $foo{$bar}
|
---|
2553 | $ref->{"susie"}[12]
|
---|
2554 |
|
---|
2555 | or a hash or array slice, such as:
|
---|
2556 |
|
---|
2557 | @foo[$bar, $baz, $xyzzy]
|
---|
2558 | @{$ref->[12]}{"susie", "queue"}
|
---|
2559 |
|
---|
2560 | =item %s argument is not a subroutine name
|
---|
2561 |
|
---|
2562 | (F) The argument to exists() for C<exists &sub> must be a subroutine
|
---|
2563 | name, and not a subroutine call. C<exists &sub()> will generate this error.
|
---|
2564 |
|
---|
2565 | =item %s package attribute may clash with future reserved word: %s
|
---|
2566 |
|
---|
2567 | (W reserved) A lowercase attribute name was used that had a package-specific handler.
|
---|
2568 | That name might have a meaning to Perl itself some day, even though it
|
---|
2569 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead.
|
---|
2570 | See L<attributes>.
|
---|
2571 |
|
---|
2572 | =item (in cleanup) %s
|
---|
2573 |
|
---|
2574 | (W misc) This prefix usually indicates that a DESTROY() method raised
|
---|
2575 | the indicated exception. Since destructors are usually called by
|
---|
2576 | the system at arbitrary points during execution, and often a vast
|
---|
2577 | number of times, the warning is issued only once for any number
|
---|
2578 | of failures that would otherwise result in the same message being
|
---|
2579 | repeated.
|
---|
2580 |
|
---|
2581 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag
|
---|
2582 | could also result in this warning. See L<perlcall/G_KEEPERR>.
|
---|
2583 |
|
---|
2584 | =item <> should be quotes
|
---|
2585 |
|
---|
2586 | (F) You wrote C<< require <file> >> when you should have written
|
---|
2587 | C<require 'file'>.
|
---|
2588 |
|
---|
2589 | =item Attempt to join self
|
---|
2590 |
|
---|
2591 | (F) You tried to join a thread from within itself, which is an
|
---|
2592 | impossible task. You may be joining the wrong thread, or you may
|
---|
2593 | need to move the join() to some other thread.
|
---|
2594 |
|
---|
2595 | =item Bad evalled substitution pattern
|
---|
2596 |
|
---|
2597 | (F) You've used the /e switch to evaluate the replacement for a
|
---|
2598 | substitution, but perl found a syntax error in the code to evaluate,
|
---|
2599 | most likely an unexpected right brace '}'.
|
---|
2600 |
|
---|
2601 | =item Bad realloc() ignored
|
---|
2602 |
|
---|
2603 | (S) An internal routine called realloc() on something that had never been
|
---|
2604 | malloc()ed in the first place. Mandatory, but can be disabled by
|
---|
2605 | setting environment variable C<PERL_BADFREE> to 1.
|
---|
2606 |
|
---|
2607 | =item Bareword found in conditional
|
---|
2608 |
|
---|
2609 | (W bareword) The compiler found a bareword where it expected a conditional,
|
---|
2610 | which often indicates that an || or && was parsed as part of the
|
---|
2611 | last argument of the previous construct, for example:
|
---|
2612 |
|
---|
2613 | open FOO || die;
|
---|
2614 |
|
---|
2615 | It may also indicate a misspelled constant that has been interpreted
|
---|
2616 | as a bareword:
|
---|
2617 |
|
---|
2618 | use constant TYPO => 1;
|
---|
2619 | if (TYOP) { print "foo" }
|
---|
2620 |
|
---|
2621 | The C<strict> pragma is useful in avoiding such errors.
|
---|
2622 |
|
---|
2623 | =item Binary number > 0b11111111111111111111111111111111 non-portable
|
---|
2624 |
|
---|
2625 | (W portable) The binary number you specified is larger than 2**32-1
|
---|
2626 | (4294967295) and therefore non-portable between systems. See
|
---|
2627 | L<perlport> for more on portability concerns.
|
---|
2628 |
|
---|
2629 | =item Bit vector size > 32 non-portable
|
---|
2630 |
|
---|
2631 | (W portable) Using bit vector sizes larger than 32 is non-portable.
|
---|
2632 |
|
---|
2633 | =item Buffer overflow in prime_env_iter: %s
|
---|
2634 |
|
---|
2635 | (W internal) A warning peculiar to VMS. While Perl was preparing to iterate over
|
---|
2636 | %ENV, it encountered a logical name or symbol definition which was too long,
|
---|
2637 | so it was truncated to the string shown.
|
---|
2638 |
|
---|
2639 | =item Can't check filesystem of script "%s"
|
---|
2640 |
|
---|
2641 | (P) For some reason you can't check the filesystem of the script for nosuid.
|
---|
2642 |
|
---|
2643 | =item Can't declare class for non-scalar %s in "%s"
|
---|
2644 |
|
---|
2645 | (S) Currently, only scalar variables can declared with a specific class
|
---|
2646 | qualifier in a "my" or "our" declaration. The semantics may be extended
|
---|
2647 | for other types of variables in future.
|
---|
2648 |
|
---|
2649 | =item Can't declare %s in "%s"
|
---|
2650 |
|
---|
2651 | (F) Only scalar, array, and hash variables may be declared as "my" or
|
---|
2652 | "our" variables. They must have ordinary identifiers as names.
|
---|
2653 |
|
---|
2654 | =item Can't ignore signal CHLD, forcing to default
|
---|
2655 |
|
---|
2656 | (W signal) Perl has detected that it is being run with the SIGCHLD signal
|
---|
2657 | (sometimes known as SIGCLD) disabled. Since disabling this signal
|
---|
2658 | will interfere with proper determination of exit status of child
|
---|
2659 | processes, Perl has reset the signal to its default value.
|
---|
2660 | This situation typically indicates that the parent program under
|
---|
2661 | which Perl may be running (e.g., cron) is being very careless.
|
---|
2662 |
|
---|
2663 | =item Can't modify non-lvalue subroutine call
|
---|
2664 |
|
---|
2665 | (F) Subroutines meant to be used in lvalue context should be declared as
|
---|
2666 | such, see L<perlsub/"Lvalue subroutines">.
|
---|
2667 |
|
---|
2668 | =item Can't read CRTL environ
|
---|
2669 |
|
---|
2670 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
|
---|
2671 | from the CRTL's internal environment array and discovered the array was
|
---|
2672 | missing. You need to figure out where your CRTL misplaced its environ
|
---|
2673 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched.
|
---|
2674 |
|
---|
2675 | =item Can't remove %s: %s, skipping file
|
---|
2676 |
|
---|
2677 | (S) You requested an inplace edit without creating a backup file. Perl
|
---|
2678 | was unable to remove the original file to replace it with the modified
|
---|
2679 | file. The file was left unmodified.
|
---|
2680 |
|
---|
2681 | =item Can't return %s from lvalue subroutine
|
---|
2682 |
|
---|
2683 | (F) Perl detected an attempt to return illegal lvalues (such
|
---|
2684 | as temporary or readonly values) from a subroutine used as an lvalue.
|
---|
2685 | This is not allowed.
|
---|
2686 |
|
---|
2687 | =item Can't weaken a nonreference
|
---|
2688 |
|
---|
2689 | (F) You attempted to weaken something that was not a reference. Only
|
---|
2690 | references can be weakened.
|
---|
2691 |
|
---|
2692 | =item Character class [:%s:] unknown
|
---|
2693 |
|
---|
2694 | (F) The class in the character class [: :] syntax is unknown.
|
---|
2695 | See L<perlre>.
|
---|
2696 |
|
---|
2697 | =item Character class syntax [%s] belongs inside character classes
|
---|
2698 |
|
---|
2699 | (W unsafe) The character class constructs [: :], [= =], and [. .] go
|
---|
2700 | I<inside> character classes, the [] are part of the construct,
|
---|
2701 | for example: /[012[:alpha:]345]/. Note that [= =] and [. .]
|
---|
2702 | are not currently implemented; they are simply placeholders for
|
---|
2703 | future extensions.
|
---|
2704 |
|
---|
2705 | =item Constant is not %s reference
|
---|
2706 |
|
---|
2707 | (F) A constant value (perhaps declared using the C<use constant> pragma)
|
---|
2708 | is being dereferenced, but it amounts to the wrong type of reference. The
|
---|
2709 | message indicates the type of reference that was expected. This usually
|
---|
2710 | indicates a syntax error in dereferencing the constant value.
|
---|
2711 | See L<perlsub/"Constant Functions"> and L<constant>.
|
---|
2712 |
|
---|
2713 | =item constant(%s): %s
|
---|
2714 |
|
---|
2715 | (F) The parser found inconsistencies either while attempting to define an
|
---|
2716 | overloaded constant, or when trying to find the character name specified
|
---|
2717 | in the C<\N{...}> escape. Perhaps you forgot to load the corresponding
|
---|
2718 | C<overload> or C<charnames> pragma? See L<charnames> and L<overload>.
|
---|
2719 |
|
---|
2720 | =item CORE::%s is not a keyword
|
---|
2721 |
|
---|
2722 | (F) The CORE:: namespace is reserved for Perl keywords.
|
---|
2723 |
|
---|
2724 | =item defined(@array) is deprecated
|
---|
2725 |
|
---|
2726 | (D) defined() is not usually useful on arrays because it checks for an
|
---|
2727 | undefined I<scalar> value. If you want to see if the array is empty,
|
---|
2728 | just use C<if (@array) { # not empty }> for example.
|
---|
2729 |
|
---|
2730 | =item defined(%hash) is deprecated
|
---|
2731 |
|
---|
2732 | (D) defined() is not usually useful on hashes because it checks for an
|
---|
2733 | undefined I<scalar> value. If you want to see if the hash is empty,
|
---|
2734 | just use C<if (%hash) { # not empty }> for example.
|
---|
2735 |
|
---|
2736 | =item Did not produce a valid header
|
---|
2737 |
|
---|
2738 | See Server error.
|
---|
2739 |
|
---|
2740 | =item (Did you mean "local" instead of "our"?)
|
---|
2741 |
|
---|
2742 | (W misc) Remember that "our" does not localize the declared global variable.
|
---|
2743 | You have declared it again in the same lexical scope, which seems superfluous.
|
---|
2744 |
|
---|
2745 | =item Document contains no data
|
---|
2746 |
|
---|
2747 | See Server error.
|
---|
2748 |
|
---|
2749 | =item entering effective %s failed
|
---|
2750 |
|
---|
2751 | (F) While under the C<use filetest> pragma, switching the real and
|
---|
2752 | effective uids or gids failed.
|
---|
2753 |
|
---|
2754 | =item false [] range "%s" in regexp
|
---|
2755 |
|
---|
2756 | (W regexp) A character class range must start and end at a literal character, not
|
---|
2757 | another character class like C<\d> or C<[:alpha:]>. The "-" in your false
|
---|
2758 | range is interpreted as a literal "-". Consider quoting the "-", "\-".
|
---|
2759 | See L<perlre>.
|
---|
2760 |
|
---|
2761 | =item Filehandle %s opened only for output
|
---|
2762 |
|
---|
2763 | (W io) You tried to read from a filehandle opened only for writing. If you
|
---|
2764 | intended it to be a read/write filehandle, you needed to open it with
|
---|
2765 | "+<" or "+>" or "+>>" instead of with "<" or nothing. If
|
---|
2766 | you intended only to read from the file, use "<". See
|
---|
2767 | L<perlfunc/open>.
|
---|
2768 |
|
---|
2769 | =item flock() on closed filehandle %s
|
---|
2770 |
|
---|
2771 | (W closed) The filehandle you're attempting to flock() got itself closed some
|
---|
2772 | time before now. Check your logic flow. flock() operates on filehandles.
|
---|
2773 | Are you attempting to call flock() on a dirhandle by the same name?
|
---|
2774 |
|
---|
2775 | =item Global symbol "%s" requires explicit package name
|
---|
2776 |
|
---|
2777 | (F) You've said "use strict vars", which indicates that all variables
|
---|
2778 | must either be lexically scoped (using "my"), declared beforehand using
|
---|
2779 | "our", or explicitly qualified to say which package the global variable
|
---|
2780 | is in (using "::").
|
---|
2781 |
|
---|
2782 | =item Hexadecimal number > 0xffffffff non-portable
|
---|
2783 |
|
---|
2784 | (W portable) The hexadecimal number you specified is larger than 2**32-1
|
---|
2785 | (4294967295) and therefore non-portable between systems. See
|
---|
2786 | L<perlport> for more on portability concerns.
|
---|
2787 |
|
---|
2788 | =item Ill-formed CRTL environ value "%s"
|
---|
2789 |
|
---|
2790 | (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's internal
|
---|
2791 | environ array, and encountered an element without the C<=> delimiter
|
---|
2792 | used to separate keys from values. The element is ignored.
|
---|
2793 |
|
---|
2794 | =item Ill-formed message in prime_env_iter: |%s|
|
---|
2795 |
|
---|
2796 | (W internal) A warning peculiar to VMS. Perl tried to read a logical name
|
---|
2797 | or CLI symbol definition when preparing to iterate over %ENV, and
|
---|
2798 | didn't see the expected delimiter between key and value, so the
|
---|
2799 | line was ignored.
|
---|
2800 |
|
---|
2801 | =item Illegal binary digit %s
|
---|
2802 |
|
---|
2803 | (F) You used a digit other than 0 or 1 in a binary number.
|
---|
2804 |
|
---|
2805 | =item Illegal binary digit %s ignored
|
---|
2806 |
|
---|
2807 | (W digit) You may have tried to use a digit other than 0 or 1 in a binary number.
|
---|
2808 | Interpretation of the binary number stopped before the offending digit.
|
---|
2809 |
|
---|
2810 | =item Illegal number of bits in vec
|
---|
2811 |
|
---|
2812 | (F) The number of bits in vec() (the third argument) must be a power of
|
---|
2813 | two from 1 to 32 (or 64, if your platform supports that).
|
---|
2814 |
|
---|
2815 | =item Integer overflow in %s number
|
---|
2816 |
|
---|
2817 | (W overflow) The hexadecimal, octal or binary number you have specified either
|
---|
2818 | as a literal or as an argument to hex() or oct() is too big for your
|
---|
2819 | architecture, and has been converted to a floating point number. On a
|
---|
2820 | 32-bit architecture the largest hexadecimal, octal or binary number
|
---|
2821 | representable without overflow is 0xFFFFFFFF, 037777777777, or
|
---|
2822 | 0b11111111111111111111111111111111 respectively. Note that Perl
|
---|
2823 | transparently promotes all numbers to a floating point representation
|
---|
2824 | internally--subject to loss of precision errors in subsequent
|
---|
2825 | operations.
|
---|
2826 |
|
---|
2827 | =item Invalid %s attribute: %s
|
---|
2828 |
|
---|
2829 | The indicated attribute for a subroutine or variable was not recognized
|
---|
2830 | by Perl or by a user-supplied handler. See L<attributes>.
|
---|
2831 |
|
---|
2832 | =item Invalid %s attributes: %s
|
---|
2833 |
|
---|
2834 | The indicated attributes for a subroutine or variable were not recognized
|
---|
2835 | by Perl or by a user-supplied handler. See L<attributes>.
|
---|
2836 |
|
---|
2837 | =item invalid [] range "%s" in regexp
|
---|
2838 |
|
---|
2839 | The offending range is now explicitly displayed.
|
---|
2840 |
|
---|
2841 | =item Invalid separator character %s in attribute list
|
---|
2842 |
|
---|
2843 | (F) Something other than a colon or whitespace was seen between the
|
---|
2844 | elements of an attribute list. If the previous attribute
|
---|
2845 | had a parenthesised parameter list, perhaps that list was terminated
|
---|
2846 | too soon. See L<attributes>.
|
---|
2847 |
|
---|
2848 | =item Invalid separator character %s in subroutine attribute list
|
---|
2849 |
|
---|
2850 | (F) Something other than a colon or whitespace was seen between the
|
---|
2851 | elements of a subroutine attribute list. If the previous attribute
|
---|
2852 | had a parenthesised parameter list, perhaps that list was terminated
|
---|
2853 | too soon.
|
---|
2854 |
|
---|
2855 | =item leaving effective %s failed
|
---|
2856 |
|
---|
2857 | (F) While under the C<use filetest> pragma, switching the real and
|
---|
2858 | effective uids or gids failed.
|
---|
2859 |
|
---|
2860 | =item Lvalue subs returning %s not implemented yet
|
---|
2861 |
|
---|
2862 | (F) Due to limitations in the current implementation, array and hash
|
---|
2863 | values cannot be returned in subroutines used in lvalue context.
|
---|
2864 | See L<perlsub/"Lvalue subroutines">.
|
---|
2865 |
|
---|
2866 | =item Method %s not permitted
|
---|
2867 |
|
---|
2868 | See Server error.
|
---|
2869 |
|
---|
2870 | =item Missing %sbrace%s on \N{}
|
---|
2871 |
|
---|
2872 | (F) Wrong syntax of character name literal C<\N{charname}> within
|
---|
2873 | double-quotish context.
|
---|
2874 |
|
---|
2875 | =item Missing command in piped open
|
---|
2876 |
|
---|
2877 | (W pipe) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
|
---|
2878 | construction, but the command was missing or blank.
|
---|
2879 |
|
---|
2880 | =item Missing name in "my sub"
|
---|
2881 |
|
---|
2882 | (F) The reserved syntax for lexically scoped subroutines requires that they
|
---|
2883 | have a name with which they can be found.
|
---|
2884 |
|
---|
2885 | =item No %s specified for -%c
|
---|
2886 |
|
---|
2887 | (F) The indicated command line switch needs a mandatory argument, but
|
---|
2888 | you haven't specified one.
|
---|
2889 |
|
---|
2890 | =item No package name allowed for variable %s in "our"
|
---|
2891 |
|
---|
2892 | (F) Fully qualified variable names are not allowed in "our" declarations,
|
---|
2893 | because that doesn't make much sense under existing semantics. Such
|
---|
2894 | syntax is reserved for future extensions.
|
---|
2895 |
|
---|
2896 | =item No space allowed after -%c
|
---|
2897 |
|
---|
2898 | (F) The argument to the indicated command line switch must follow immediately
|
---|
2899 | after the switch, without intervening spaces.
|
---|
2900 |
|
---|
2901 | =item no UTC offset information; assuming local time is UTC
|
---|
2902 |
|
---|
2903 | (S) A warning peculiar to VMS. Perl was unable to find the local
|
---|
2904 | timezone offset, so it's assuming that local system time is equivalent
|
---|
2905 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL>
|
---|
2906 | to translate to the number of seconds which need to be added to UTC to
|
---|
2907 | get local time.
|
---|
2908 |
|
---|
2909 | =item Octal number > 037777777777 non-portable
|
---|
2910 |
|
---|
2911 | (W portable) The octal number you specified is larger than 2**32-1 (4294967295)
|
---|
2912 | and therefore non-portable between systems. See L<perlport> for more
|
---|
2913 | on portability concerns.
|
---|
2914 |
|
---|
2915 | See also L<perlport> for writing portable code.
|
---|
2916 |
|
---|
2917 | =item panic: del_backref
|
---|
2918 |
|
---|
2919 | (P) Failed an internal consistency check while trying to reset a weak
|
---|
2920 | reference.
|
---|
2921 |
|
---|
2922 | =item panic: kid popen errno read
|
---|
2923 |
|
---|
2924 | (F) forked child returned an incomprehensible message about its errno.
|
---|
2925 |
|
---|
2926 | =item panic: magic_killbackrefs
|
---|
2927 |
|
---|
2928 | (P) Failed an internal consistency check while trying to reset all weak
|
---|
2929 | references to an object.
|
---|
2930 |
|
---|
2931 | =item Parentheses missing around "%s" list
|
---|
2932 |
|
---|
2933 | (W parenthesis) You said something like
|
---|
2934 |
|
---|
2935 | my $foo, $bar = @_;
|
---|
2936 |
|
---|
2937 | when you meant
|
---|
2938 |
|
---|
2939 | my ($foo, $bar) = @_;
|
---|
2940 |
|
---|
2941 | Remember that "my", "our", and "local" bind tighter than comma.
|
---|
2942 |
|
---|
2943 | =item Possible unintended interpolation of %s in string
|
---|
2944 |
|
---|
2945 | (W ambiguous) It used to be that Perl would try to guess whether you
|
---|
2946 | wanted an array interpolated or a literal @. It no longer does this;
|
---|
2947 | arrays are now I<always> interpolated into strings. This means that
|
---|
2948 | if you try something like:
|
---|
2949 |
|
---|
2950 | print "[email protected]";
|
---|
2951 |
|
---|
2952 | and the array C<@example> doesn't exist, Perl is going to print
|
---|
2953 | C<fred.com>, which is probably not what you wanted. To get a literal
|
---|
2954 | C<@> sign in a string, put a backslash before it, just as you would
|
---|
2955 | to get a literal C<$> sign.
|
---|
2956 |
|
---|
2957 | =item Possible Y2K bug: %s
|
---|
2958 |
|
---|
2959 | (W y2k) You are concatenating the number 19 with another number, which
|
---|
2960 | could be a potential Year 2000 problem.
|
---|
2961 |
|
---|
2962 | =item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
|
---|
2963 |
|
---|
2964 | (W deprecated) You have written something like this:
|
---|
2965 |
|
---|
2966 | sub doit
|
---|
2967 | {
|
---|
2968 | use attrs qw(locked);
|
---|
2969 | }
|
---|
2970 |
|
---|
2971 | You should use the new declaration syntax instead.
|
---|
2972 |
|
---|
2973 | sub doit : locked
|
---|
2974 | {
|
---|
2975 | ...
|
---|
2976 |
|
---|
2977 | The C<use attrs> pragma is now obsolete, and is only provided for
|
---|
2978 | backward-compatibility. See L<perlsub/"Subroutine Attributes">.
|
---|
2979 |
|
---|
2980 |
|
---|
2981 | =item Premature end of script headers
|
---|
2982 |
|
---|
2983 | See Server error.
|
---|
2984 |
|
---|
2985 | =item Repeat count in pack overflows
|
---|
2986 |
|
---|
2987 | (F) You can't specify a repeat count so large that it overflows
|
---|
2988 | your signed integers. See L<perlfunc/pack>.
|
---|
2989 |
|
---|
2990 | =item Repeat count in unpack overflows
|
---|
2991 |
|
---|
2992 | (F) You can't specify a repeat count so large that it overflows
|
---|
2993 | your signed integers. See L<perlfunc/unpack>.
|
---|
2994 |
|
---|
2995 | =item realloc() of freed memory ignored
|
---|
2996 |
|
---|
2997 | (S) An internal routine called realloc() on something that had already
|
---|
2998 | been freed.
|
---|
2999 |
|
---|
3000 | =item Reference is already weak
|
---|
3001 |
|
---|
3002 | (W misc) You have attempted to weaken a reference that is already weak.
|
---|
3003 | Doing so has no effect.
|
---|
3004 |
|
---|
3005 | =item setpgrp can't take arguments
|
---|
3006 |
|
---|
3007 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments,
|
---|
3008 | unlike POSIX setpgid(), which takes a process ID and process group ID.
|
---|
3009 |
|
---|
3010 | =item Strange *+?{} on zero-length expression
|
---|
3011 |
|
---|
3012 | (W regexp) You applied a regular expression quantifier in a place where it
|
---|
3013 | makes no sense, such as on a zero-width assertion.
|
---|
3014 | Try putting the quantifier inside the assertion instead. For example,
|
---|
3015 | the way to match "abc" provided that it is followed by three
|
---|
3016 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
|
---|
3017 |
|
---|
3018 | =item switching effective %s is not implemented
|
---|
3019 |
|
---|
3020 | (F) While under the C<use filetest> pragma, we cannot switch the
|
---|
3021 | real and effective uids or gids.
|
---|
3022 |
|
---|
3023 | =item This Perl can't reset CRTL environ elements (%s)
|
---|
3024 |
|
---|
3025 | =item This Perl can't set CRTL environ elements (%s=%s)
|
---|
3026 |
|
---|
3027 | (W internal) Warnings peculiar to VMS. You tried to change or delete an element
|
---|
3028 | of the CRTL's internal environ array, but your copy of Perl wasn't
|
---|
3029 | built with a CRTL that contained the setenv() function. You'll need to
|
---|
3030 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see
|
---|
3031 | L<perlvms>) so that the environ array isn't the target of the change to
|
---|
3032 | %ENV which produced the warning.
|
---|
3033 |
|
---|
3034 | =item Too late to run %s block
|
---|
3035 |
|
---|
3036 | (W void) A CHECK or INIT block is being defined during run time proper,
|
---|
3037 | when the opportunity to run them has already passed. Perhaps you are
|
---|
3038 | loading a file with C<require> or C<do> when you should be using
|
---|
3039 | C<use> instead. Or perhaps you should put the C<require> or C<do>
|
---|
3040 | inside a BEGIN block.
|
---|
3041 |
|
---|
3042 | =item Unknown open() mode '%s'
|
---|
3043 |
|
---|
3044 | (F) The second argument of 3-argument open() is not among the list
|
---|
3045 | of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
|
---|
3046 | C<< +> >>, C<<< +>> >>>, C<-|>, C<|->.
|
---|
3047 |
|
---|
3048 | =item Unknown process %x sent message to prime_env_iter: %s
|
---|
3049 |
|
---|
3050 | (P) An error peculiar to VMS. Perl was reading values for %ENV before
|
---|
3051 | iterating over it, and someone else stuck a message in the stream of
|
---|
3052 | data Perl expected. Someone's very confused, or perhaps trying to
|
---|
3053 | subvert Perl's population of %ENV for nefarious purposes.
|
---|
3054 |
|
---|
3055 | =item Unrecognized escape \\%c passed through
|
---|
3056 |
|
---|
3057 | (W misc) You used a backslash-character combination which is not recognized
|
---|
3058 | by Perl. The character was understood literally.
|
---|
3059 |
|
---|
3060 | =item Unterminated attribute parameter in attribute list
|
---|
3061 |
|
---|
3062 | (F) The lexer saw an opening (left) parenthesis character while parsing an
|
---|
3063 | attribute list, but the matching closing (right) parenthesis
|
---|
3064 | character was not found. You may need to add (or remove) a backslash
|
---|
3065 | character to get your parentheses to balance. See L<attributes>.
|
---|
3066 |
|
---|
3067 | =item Unterminated attribute list
|
---|
3068 |
|
---|
3069 | (F) The lexer found something other than a simple identifier at the start
|
---|
3070 | of an attribute, and it wasn't a semicolon or the start of a
|
---|
3071 | block. Perhaps you terminated the parameter list of the previous attribute
|
---|
3072 | too soon. See L<attributes>.
|
---|
3073 |
|
---|
3074 | =item Unterminated attribute parameter in subroutine attribute list
|
---|
3075 |
|
---|
3076 | (F) The lexer saw an opening (left) parenthesis character while parsing a
|
---|
3077 | subroutine attribute list, but the matching closing (right) parenthesis
|
---|
3078 | character was not found. You may need to add (or remove) a backslash
|
---|
3079 | character to get your parentheses to balance.
|
---|
3080 |
|
---|
3081 | =item Unterminated subroutine attribute list
|
---|
3082 |
|
---|
3083 | (F) The lexer found something other than a simple identifier at the start
|
---|
3084 | of a subroutine attribute, and it wasn't a semicolon or the start of a
|
---|
3085 | block. Perhaps you terminated the parameter list of the previous attribute
|
---|
3086 | too soon.
|
---|
3087 |
|
---|
3088 | =item Value of CLI symbol "%s" too long
|
---|
3089 |
|
---|
3090 | (W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV
|
---|
3091 | element from a CLI symbol table, and found a resultant string longer
|
---|
3092 | than 1024 characters. The return value has been truncated to 1024
|
---|
3093 | characters.
|
---|
3094 |
|
---|
3095 | =item Version number must be a constant number
|
---|
3096 |
|
---|
3097 | (P) The attempt to translate a C<use Module n.n LIST> statement into
|
---|
3098 | its equivalent C<BEGIN> block found an internal inconsistency with
|
---|
3099 | the version number.
|
---|
3100 |
|
---|
3101 | =back
|
---|
3102 |
|
---|
3103 | =head1 New tests
|
---|
3104 |
|
---|
3105 | =over 4
|
---|
3106 |
|
---|
3107 | =item lib/attrs
|
---|
3108 |
|
---|
3109 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>.
|
---|
3110 |
|
---|
3111 | =item lib/env
|
---|
3112 |
|
---|
3113 | Tests for new environment scalar capability (e.g., C<use Env qw($BAR);>).
|
---|
3114 |
|
---|
3115 | =item lib/env-array
|
---|
3116 |
|
---|
3117 | Tests for new environment array capability (e.g., C<use Env qw(@PATH);>).
|
---|
3118 |
|
---|
3119 | =item lib/io_const
|
---|
3120 |
|
---|
3121 | IO constants (SEEK_*, _IO*).
|
---|
3122 |
|
---|
3123 | =item lib/io_dir
|
---|
3124 |
|
---|
3125 | Directory-related IO methods (new, read, close, rewind, tied delete).
|
---|
3126 |
|
---|
3127 | =item lib/io_multihomed
|
---|
3128 |
|
---|
3129 | INET sockets with multi-homed hosts.
|
---|
3130 |
|
---|
3131 | =item lib/io_poll
|
---|
3132 |
|
---|
3133 | IO poll().
|
---|
3134 |
|
---|
3135 | =item lib/io_unix
|
---|
3136 |
|
---|
3137 | UNIX sockets.
|
---|
3138 |
|
---|
3139 | =item op/attrs
|
---|
3140 |
|
---|
3141 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>.
|
---|
3142 |
|
---|
3143 | =item op/filetest
|
---|
3144 |
|
---|
3145 | File test operators.
|
---|
3146 |
|
---|
3147 | =item op/lex_assign
|
---|
3148 |
|
---|
3149 | Verify operations that access pad objects (lexicals and temporaries).
|
---|
3150 |
|
---|
3151 | =item op/exists_sub
|
---|
3152 |
|
---|
3153 | Verify C<exists &sub> operations.
|
---|
3154 |
|
---|
3155 | =back
|
---|
3156 |
|
---|
3157 | =head1 Incompatible Changes
|
---|
3158 |
|
---|
3159 | =head2 Perl Source Incompatibilities
|
---|
3160 |
|
---|
3161 | Beware that any new warnings that have been added or old ones
|
---|
3162 | that have been enhanced are B<not> considered incompatible changes.
|
---|
3163 |
|
---|
3164 | Since all new warnings must be explicitly requested via the C<-w>
|
---|
3165 | switch or the C<warnings> pragma, it is ultimately the programmer's
|
---|
3166 | responsibility to ensure that warnings are enabled judiciously.
|
---|
3167 |
|
---|
3168 | =over 4
|
---|
3169 |
|
---|
3170 | =item CHECK is a new keyword
|
---|
3171 |
|
---|
3172 | All subroutine definitions named CHECK are now special. See
|
---|
3173 | C</"Support for CHECK blocks"> for more information.
|
---|
3174 |
|
---|
3175 | =item Treatment of list slices of undef has changed
|
---|
3176 |
|
---|
3177 | There is a potential incompatibility in the behavior of list slices
|
---|
3178 | that are comprised entirely of undefined values.
|
---|
3179 | See L</"Behavior of list slices is more consistent">.
|
---|
3180 |
|
---|
3181 | =item Format of $English::PERL_VERSION is different
|
---|
3182 |
|
---|
3183 | The English module now sets $PERL_VERSION to $^V (a string value) rather
|
---|
3184 | than C<$]> (a numeric value). This is a potential incompatibility.
|
---|
3185 | Send us a report via perlbug if you are affected by this.
|
---|
3186 |
|
---|
3187 | See L</"Improved Perl version numbering system"> for the reasons for
|
---|
3188 | this change.
|
---|
3189 |
|
---|
3190 | =item Literals of the form C<1.2.3> parse differently
|
---|
3191 |
|
---|
3192 | Previously, numeric literals with more than one dot in them were
|
---|
3193 | interpreted as a floating point number concatenated with one or more
|
---|
3194 | numbers. Such "numbers" are now parsed as strings composed of the
|
---|
3195 | specified ordinals.
|
---|
3196 |
|
---|
3197 | For example, C<print 97.98.99> used to output C<97.9899> in earlier
|
---|
3198 | versions, but now prints C<abc>.
|
---|
3199 |
|
---|
3200 | See L</"Support for strings represented as a vector of ordinals">.
|
---|
3201 |
|
---|
3202 | =item Possibly changed pseudo-random number generator
|
---|
3203 |
|
---|
3204 | Perl programs that depend on reproducing a specific set of pseudo-random
|
---|
3205 | numbers may now produce different output due to improvements made to the
|
---|
3206 | rand() builtin. You can use C<sh Configure -Drandfunc=rand> to obtain
|
---|
3207 | the old behavior.
|
---|
3208 |
|
---|
3209 | See L</"Better pseudo-random number generator">.
|
---|
3210 |
|
---|
3211 | =item Hashing function for hash keys has changed
|
---|
3212 |
|
---|
3213 | Even though Perl hashes are not order preserving, the apparently
|
---|
3214 | random order encountered when iterating on the contents of a hash
|
---|
3215 | is actually determined by the hashing algorithm used. Improvements
|
---|
3216 | in the algorithm may yield a random order that is B<different> from
|
---|
3217 | that of previous versions, especially when iterating on hashes.
|
---|
3218 |
|
---|
3219 | See L</"Better worst-case behavior of hashes"> for additional
|
---|
3220 | information.
|
---|
3221 |
|
---|
3222 | =item C<undef> fails on read only values
|
---|
3223 |
|
---|
3224 | Using the C<undef> operator on a readonly value (such as $1) has
|
---|
3225 | the same effect as assigning C<undef> to the readonly value--it
|
---|
3226 | throws an exception.
|
---|
3227 |
|
---|
3228 | =item Close-on-exec bit may be set on pipe and socket handles
|
---|
3229 |
|
---|
3230 | Pipe and socket handles are also now subject to the close-on-exec
|
---|
3231 | behavior determined by the special variable $^F.
|
---|
3232 |
|
---|
3233 | See L</"More consistent close-on-exec behavior">.
|
---|
3234 |
|
---|
3235 | =item Writing C<"$$1"> to mean C<"${$}1"> is unsupported
|
---|
3236 |
|
---|
3237 | Perl 5.004 deprecated the interpretation of C<$$1> and
|
---|
3238 | similar within interpolated strings to mean C<$$ . "1">,
|
---|
3239 | but still allowed it.
|
---|
3240 |
|
---|
3241 | In Perl 5.6.0 and later, C<"$$1"> always means C<"${$1}">.
|
---|
3242 |
|
---|
3243 | =item delete(), each(), values() and C<\(%h)>
|
---|
3244 |
|
---|
3245 | operate on aliases to values, not copies
|
---|
3246 |
|
---|
3247 | delete(), each(), values() and hashes (e.g. C<\(%h)>)
|
---|
3248 | in a list context return the actual
|
---|
3249 | values in the hash, instead of copies (as they used to in earlier
|
---|
3250 | versions). Typical idioms for using these constructs copy the
|
---|
3251 | returned values, but this can make a significant difference when
|
---|
3252 | creating references to the returned values. Keys in the hash are still
|
---|
3253 | returned as copies when iterating on a hash.
|
---|
3254 |
|
---|
3255 | See also L</"delete(), each(), values() and hash iteration are faster">.
|
---|
3256 |
|
---|
3257 | =item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS
|
---|
3258 |
|
---|
3259 | vec() generates a run-time error if the BITS argument is not
|
---|
3260 | a valid power-of-two integer.
|
---|
3261 |
|
---|
3262 | =item Text of some diagnostic output has changed
|
---|
3263 |
|
---|
3264 | Most references to internal Perl operations in diagnostics
|
---|
3265 | have been changed to be more descriptive. This may be an
|
---|
3266 | issue for programs that may incorrectly rely on the exact
|
---|
3267 | text of diagnostics for proper functioning.
|
---|
3268 |
|
---|
3269 | =item C<%@> has been removed
|
---|
3270 |
|
---|
3271 | The undocumented special variable C<%@> that used to accumulate
|
---|
3272 | "background" errors (such as those that happen in DESTROY())
|
---|
3273 | has been removed, because it could potentially result in memory
|
---|
3274 | leaks.
|
---|
3275 |
|
---|
3276 | =item Parenthesized not() behaves like a list operator
|
---|
3277 |
|
---|
3278 | The C<not> operator now falls under the "if it looks like a function,
|
---|
3279 | it behaves like a function" rule.
|
---|
3280 |
|
---|
3281 | As a result, the parenthesized form can be used with C<grep> and C<map>.
|
---|
3282 | The following construct used to be a syntax error before, but it works
|
---|
3283 | as expected now:
|
---|
3284 |
|
---|
3285 | grep not($_), @things;
|
---|
3286 |
|
---|
3287 | On the other hand, using C<not> with a literal list slice may not
|
---|
3288 | work. The following previously allowed construct:
|
---|
3289 |
|
---|
3290 | print not (1,2,3)[0];
|
---|
3291 |
|
---|
3292 | needs to be written with additional parentheses now:
|
---|
3293 |
|
---|
3294 | print not((1,2,3)[0]);
|
---|
3295 |
|
---|
3296 | The behavior remains unaffected when C<not> is not followed by parentheses.
|
---|
3297 |
|
---|
3298 | =item Semantics of bareword prototype C<(*)> have changed
|
---|
3299 |
|
---|
3300 | The semantics of the bareword prototype C<*> have changed. Perl 5.005
|
---|
3301 | always coerced simple scalar arguments to a typeglob, which wasn't useful
|
---|
3302 | in situations where the subroutine must distinguish between a simple
|
---|
3303 | scalar and a typeglob. The new behavior is to not coerce bareword
|
---|
3304 | arguments to a typeglob. The value will always be visible as either
|
---|
3305 | a simple scalar or as a reference to a typeglob.
|
---|
3306 |
|
---|
3307 | See L</"More functional bareword prototype (*)">.
|
---|
3308 |
|
---|
3309 | =item Semantics of bit operators may have changed on 64-bit platforms
|
---|
3310 |
|
---|
3311 | If your platform is either natively 64-bit or if Perl has been
|
---|
3312 | configured to used 64-bit integers, i.e., $Config{ivsize} is 8,
|
---|
3313 | there may be a potential incompatibility in the behavior of bitwise
|
---|
3314 | numeric operators (& | ^ ~ << >>). These operators used to strictly
|
---|
3315 | operate on the lower 32 bits of integers in previous versions, but now
|
---|
3316 | operate over the entire native integral width. In particular, note
|
---|
3317 | that unary C<~> will produce different results on platforms that have
|
---|
3318 | different $Config{ivsize}. For portability, be sure to mask off
|
---|
3319 | the excess bits in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
|
---|
3320 |
|
---|
3321 | See L</"Bit operators support full native integer width">.
|
---|
3322 |
|
---|
3323 | =item More builtins taint their results
|
---|
3324 |
|
---|
3325 | As described in L</"Improved security features">, there may be more
|
---|
3326 | sources of taint in a Perl program.
|
---|
3327 |
|
---|
3328 | To avoid these new tainting behaviors, you can build Perl with the
|
---|
3329 | Configure option C<-Accflags=-DINCOMPLETE_TAINTS>. Beware that the
|
---|
3330 | ensuing perl binary may be insecure.
|
---|
3331 |
|
---|
3332 | =back
|
---|
3333 |
|
---|
3334 | =head2 C Source Incompatibilities
|
---|
3335 |
|
---|
3336 | =over 4
|
---|
3337 |
|
---|
3338 | =item C<PERL_POLLUTE>
|
---|
3339 |
|
---|
3340 | Release 5.005 grandfathered old global symbol names by providing preprocessor
|
---|
3341 | macros for extension source compatibility. As of release 5.6.0, these
|
---|
3342 | preprocessor definitions are not available by default. You need to explicitly
|
---|
3343 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For
|
---|
3344 | extensions still using the old symbols, this option can be
|
---|
3345 | specified via MakeMaker:
|
---|
3346 |
|
---|
3347 | perl Makefile.PL POLLUTE=1
|
---|
3348 |
|
---|
3349 | =item C<PERL_IMPLICIT_CONTEXT>
|
---|
3350 |
|
---|
3351 | This new build option provides a set of macros for all API functions
|
---|
3352 | such that an implicit interpreter/thread context argument is passed to
|
---|
3353 | every API function. As a result of this, something like C<sv_setsv(foo,bar)>
|
---|
3354 | amounts to a macro invocation that actually translates to something like
|
---|
3355 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected
|
---|
3356 | to not have any significant source compatibility issues, the difference
|
---|
3357 | between a macro and a real function call will need to be considered.
|
---|
3358 |
|
---|
3359 | This means that there B<is> a source compatibility issue as a result of
|
---|
3360 | this if your extensions attempt to use pointers to any of the Perl API
|
---|
3361 | functions.
|
---|
3362 |
|
---|
3363 | Note that the above issue is not relevant to the default build of
|
---|
3364 | Perl, whose interfaces continue to match those of prior versions
|
---|
3365 | (but subject to the other options described here).
|
---|
3366 |
|
---|
3367 | See L<perlguts/"The Perl API"> for detailed information on the
|
---|
3368 | ramifications of building Perl with this option.
|
---|
3369 |
|
---|
3370 | NOTE: PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built
|
---|
3371 | with one of -Dusethreads, -Dusemultiplicity, or both. It is not
|
---|
3372 | intended to be enabled by users at this time.
|
---|
3373 |
|
---|
3374 | =item C<PERL_POLLUTE_MALLOC>
|
---|
3375 |
|
---|
3376 | Enabling Perl's malloc in release 5.005 and earlier caused the namespace of
|
---|
3377 | the system's malloc family of functions to be usurped by the Perl versions,
|
---|
3378 | since by default they used the same names. Besides causing problems on
|
---|
3379 | platforms that do not allow these functions to be cleanly replaced, this
|
---|
3380 | also meant that the system versions could not be called in programs that
|
---|
3381 | used Perl's malloc. Previous versions of Perl have allowed this behaviour
|
---|
3382 | to be suppressed with the HIDEMYMALLOC and EMBEDMYMALLOC preprocessor
|
---|
3383 | definitions.
|
---|
3384 |
|
---|
3385 | As of release 5.6.0, Perl's malloc family of functions have default names
|
---|
3386 | distinct from the system versions. You need to explicitly compile perl with
|
---|
3387 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC
|
---|
3388 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now
|
---|
3389 | the default.
|
---|
3390 |
|
---|
3391 | Note that these functions do B<not> constitute Perl's memory allocation API.
|
---|
3392 | See L<perlguts/"Memory Allocation"> for further information about that.
|
---|
3393 |
|
---|
3394 | =back
|
---|
3395 |
|
---|
3396 | =head2 Compatible C Source API Changes
|
---|
3397 |
|
---|
3398 | =over 4
|
---|
3399 |
|
---|
3400 | =item C<PATCHLEVEL> is now C<PERL_VERSION>
|
---|
3401 |
|
---|
3402 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION>
|
---|
3403 | are now available by default from perl.h, and reflect the base revision,
|
---|
3404 | patchlevel, and subversion respectively. C<PERL_REVISION> had no
|
---|
3405 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were
|
---|
3406 | previously available as C<PATCHLEVEL> and C<SUBVERSION>.
|
---|
3407 |
|
---|
3408 | The new names cause less pollution of the B<cpp> namespace and reflect what
|
---|
3409 | the numbers have come to stand for in common practice. For compatibility,
|
---|
3410 | the old names are still supported when F<patchlevel.h> is explicitly
|
---|
3411 | included (as required before), so there is no source incompatibility
|
---|
3412 | from the change.
|
---|
3413 |
|
---|
3414 | =back
|
---|
3415 |
|
---|
3416 | =head2 Binary Incompatibilities
|
---|
3417 |
|
---|
3418 | In general, the default build of this release is expected to be binary
|
---|
3419 | compatible for extensions built with the 5.005 release or its maintenance
|
---|
3420 | versions. However, specific platforms may have broken binary compatibility
|
---|
3421 | due to changes in the defaults used in hints files. Therefore, please be
|
---|
3422 | sure to always check the platform-specific README files for any notes to
|
---|
3423 | the contrary.
|
---|
3424 |
|
---|
3425 | The usethreads or usemultiplicity builds are B<not> binary compatible
|
---|
3426 | with the corresponding builds in 5.005.
|
---|
3427 |
|
---|
3428 | On platforms that require an explicit list of exports (AIX, OS/2 and Windows,
|
---|
3429 | among others), purely internal symbols such as parser functions and the
|
---|
3430 | run time opcodes are not exported by default. Perl 5.005 used to export
|
---|
3431 | all functions irrespective of whether they were considered part of the
|
---|
3432 | public API or not.
|
---|
3433 |
|
---|
3434 | For the full list of public API functions, see L<perlapi>.
|
---|
3435 |
|
---|
3436 | =head1 Known Problems
|
---|
3437 |
|
---|
3438 | =head2 Localizing a tied hash element may leak memory
|
---|
3439 |
|
---|
3440 | As of the 5.6.1 release, there is a known leak when code such as this
|
---|
3441 | is executed:
|
---|
3442 |
|
---|
3443 | use Tie::Hash;
|
---|
3444 | tie my %tie_hash => 'Tie::StdHash';
|
---|
3445 |
|
---|
3446 | ...
|
---|
3447 |
|
---|
3448 | local($tie_hash{Foo}) = 1; # leaks
|
---|
3449 |
|
---|
3450 | =head2 Known test failures
|
---|
3451 |
|
---|
3452 | =over
|
---|
3453 |
|
---|
3454 | =item *
|
---|
3455 |
|
---|
3456 | 64-bit builds
|
---|
3457 |
|
---|
3458 | Subtest #15 of lib/b.t may fail under 64-bit builds on platforms such
|
---|
3459 | as HP-UX PA64 and Linux IA64. The issue is still being investigated.
|
---|
3460 |
|
---|
3461 | The lib/io_multihomed test may hang in HP-UX if Perl has been
|
---|
3462 | configured to be 64-bit. Because other 64-bit platforms do not
|
---|
3463 | hang in this test, HP-UX is suspect. All other tests pass
|
---|
3464 | in 64-bit HP-UX. The test attempts to create and connect to
|
---|
3465 | "multihomed" sockets (sockets which have multiple IP addresses).
|
---|
3466 |
|
---|
3467 | Note that 64-bit support is still experimental.
|
---|
3468 |
|
---|
3469 | =item *
|
---|
3470 |
|
---|
3471 | Failure of Thread tests
|
---|
3472 |
|
---|
3473 | The subtests 19 and 20 of lib/thr5005.t test are known to fail due to
|
---|
3474 | fundamental problems in the 5.005 threading implementation. These are
|
---|
3475 | not new failures--Perl 5.005_0x has the same bugs, but didn't have these
|
---|
3476 | tests. (Note that support for 5.005-style threading remains experimental.)
|
---|
3477 |
|
---|
3478 | =item *
|
---|
3479 |
|
---|
3480 | NEXTSTEP 3.3 POSIX test failure
|
---|
3481 |
|
---|
3482 | In NEXTSTEP 3.3p2 the implementation of the strftime(3) in the
|
---|
3483 | operating system libraries is buggy: the %j format numbers the days of
|
---|
3484 | a month starting from zero, which, while being logical to programmers,
|
---|
3485 | will cause the subtests 19 to 27 of the lib/posix test may fail.
|
---|
3486 |
|
---|
3487 | =item *
|
---|
3488 |
|
---|
3489 | Tru64 (aka Digital UNIX, aka DEC OSF/1) lib/sdbm test failure with gcc
|
---|
3490 |
|
---|
3491 | If compiled with gcc 2.95 the lib/sdbm test will fail (dump core).
|
---|
3492 | The cure is to use the vendor cc, it comes with the operating system
|
---|
3493 | and produces good code.
|
---|
3494 |
|
---|
3495 | =back
|
---|
3496 |
|
---|
3497 | =head2 EBCDIC platforms not fully supported
|
---|
3498 |
|
---|
3499 | In earlier releases of Perl, EBCDIC environments like OS390 (also
|
---|
3500 | known as Open Edition MVS) and VM-ESA were supported. Due to changes
|
---|
3501 | required by the UTF-8 (Unicode) support, the EBCDIC platforms are not
|
---|
3502 | supported in Perl 5.6.0.
|
---|
3503 |
|
---|
3504 | The 5.6.1 release improves support for EBCDIC platforms, but they
|
---|
3505 | are not fully supported yet.
|
---|
3506 |
|
---|
3507 | =head2 UNICOS/mk CC failures during Configure run
|
---|
3508 |
|
---|
3509 | In UNICOS/mk the following errors may appear during the Configure run:
|
---|
3510 |
|
---|
3511 | Guessing which symbols your C compiler and preprocessor define...
|
---|
3512 | CC-20 cc: ERROR File = try.c, Line = 3
|
---|
3513 | ...
|
---|
3514 | bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
|
---|
3515 | ...
|
---|
3516 | 4 errors detected in the compilation of "try.c".
|
---|
3517 |
|
---|
3518 | The culprit is the broken awk of UNICOS/mk. The effect is fortunately
|
---|
3519 | rather mild: Perl itself is not adversely affected by the error, only
|
---|
3520 | the h2ph utility coming with Perl, and that is rather rarely needed
|
---|
3521 | these days.
|
---|
3522 |
|
---|
3523 | =head2 Arrow operator and arrays
|
---|
3524 |
|
---|
3525 | When the left argument to the arrow operator C<< -> >> is an array, or
|
---|
3526 | the C<scalar> operator operating on an array, the result of the
|
---|
3527 | operation must be considered erroneous. For example:
|
---|
3528 |
|
---|
3529 | @x->[2]
|
---|
3530 | scalar(@x)->[2]
|
---|
3531 |
|
---|
3532 | These expressions will get run-time errors in some future release of
|
---|
3533 | Perl.
|
---|
3534 |
|
---|
3535 | =head2 Experimental features
|
---|
3536 |
|
---|
3537 | As discussed above, many features are still experimental. Interfaces and
|
---|
3538 | implementation of these features are subject to change, and in extreme cases,
|
---|
3539 | even subject to removal in some future release of Perl. These features
|
---|
3540 | include the following:
|
---|
3541 |
|
---|
3542 | =over 4
|
---|
3543 |
|
---|
3544 | =item Threads
|
---|
3545 |
|
---|
3546 | =item Unicode
|
---|
3547 |
|
---|
3548 | =item 64-bit support
|
---|
3549 |
|
---|
3550 | =item Lvalue subroutines
|
---|
3551 |
|
---|
3552 | =item Weak references
|
---|
3553 |
|
---|
3554 | =item The pseudo-hash data type
|
---|
3555 |
|
---|
3556 | =item The Compiler suite
|
---|
3557 |
|
---|
3558 | =item Internal implementation of file globbing
|
---|
3559 |
|
---|
3560 | =item The DB module
|
---|
3561 |
|
---|
3562 | =item The regular expression code constructs:
|
---|
3563 |
|
---|
3564 | C<(?{ code })> and C<(??{ code })>
|
---|
3565 |
|
---|
3566 | =back
|
---|
3567 |
|
---|
3568 | =head1 Obsolete Diagnostics
|
---|
3569 |
|
---|
3570 | =over 4
|
---|
3571 |
|
---|
3572 | =item Character class syntax [: :] is reserved for future extensions
|
---|
3573 |
|
---|
3574 | (W) Within regular expression character classes ([]) the syntax beginning
|
---|
3575 | with "[:" and ending with ":]" is reserved for future extensions.
|
---|
3576 | If you need to represent those character sequences inside a regular
|
---|
3577 | expression character class, just quote the square brackets with the
|
---|
3578 | backslash: "\[:" and ":\]".
|
---|
3579 |
|
---|
3580 | =item Ill-formed logical name |%s| in prime_env_iter
|
---|
3581 |
|
---|
3582 | (W) A warning peculiar to VMS. A logical name was encountered when preparing
|
---|
3583 | to iterate over %ENV which violates the syntactic rules governing logical
|
---|
3584 | names. Because it cannot be translated normally, it is skipped, and will not
|
---|
3585 | appear in %ENV. This may be a benign occurrence, as some software packages
|
---|
3586 | might directly modify logical name tables and introduce nonstandard names,
|
---|
3587 | or it may indicate that a logical name table has been corrupted.
|
---|
3588 |
|
---|
3589 | =item In string, @%s now must be written as \@%s
|
---|
3590 |
|
---|
3591 | The description of this error used to say:
|
---|
3592 |
|
---|
3593 | (Someday it will simply assume that an unbackslashed @
|
---|
3594 | interpolates an array.)
|
---|
3595 |
|
---|
3596 | That day has come, and this fatal error has been removed. It has been
|
---|
3597 | replaced by a non-fatal warning instead.
|
---|
3598 | See L</Arrays now always interpolate into double-quoted strings> for
|
---|
3599 | details.
|
---|
3600 |
|
---|
3601 | =item Probable precedence problem on %s
|
---|
3602 |
|
---|
3603 | (W) The compiler found a bareword where it expected a conditional,
|
---|
3604 | which often indicates that an || or && was parsed as part of the
|
---|
3605 | last argument of the previous construct, for example:
|
---|
3606 |
|
---|
3607 | open FOO || die;
|
---|
3608 |
|
---|
3609 | =item regexp too big
|
---|
3610 |
|
---|
3611 | (F) The current implementation of regular expressions uses shorts as
|
---|
3612 | address offsets within a string. Unfortunately this means that if
|
---|
3613 | the regular expression compiles to longer than 32767, it'll blow up.
|
---|
3614 | Usually when you want a regular expression this big, there is a better
|
---|
3615 | way to do it with multiple statements. See L<perlre>.
|
---|
3616 |
|
---|
3617 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated
|
---|
3618 |
|
---|
3619 | (D) Perl versions before 5.004 misinterpreted any type marker followed
|
---|
3620 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean
|
---|
3621 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004.
|
---|
3622 |
|
---|
3623 | However, the developers of Perl 5.004 could not fix this bug completely,
|
---|
3624 | because at least two widely-used modules depend on the old meaning of
|
---|
3625 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the
|
---|
3626 | old (broken) way inside strings; but it generates this message as a
|
---|
3627 | warning. And in Perl 5.005, this special treatment will cease.
|
---|
3628 |
|
---|
3629 | =back
|
---|
3630 |
|
---|
3631 | =head1 Reporting Bugs
|
---|
3632 |
|
---|
3633 | If you find what you think is a bug, you might check the
|
---|
3634 | articles recently posted to the comp.lang.perl.misc newsgroup.
|
---|
3635 | There may also be information at http://www.perl.com/ , the Perl
|
---|
3636 | Home Page.
|
---|
3637 |
|
---|
3638 | If you believe you have an unreported bug, please run the B<perlbug>
|
---|
3639 | program included with your release. Be sure to trim your bug down
|
---|
3640 | to a tiny but sufficient test case. Your bug report, along with the
|
---|
3641 | output of C<perl -V>, will be sent off to [email protected] to be
|
---|
3642 | analysed by the Perl porting team.
|
---|
3643 |
|
---|
3644 | =head1 SEE ALSO
|
---|
3645 |
|
---|
3646 | The F<Changes> file for exhaustive details on what changed.
|
---|
3647 |
|
---|
3648 | The F<INSTALL> file for how to build Perl.
|
---|
3649 |
|
---|
3650 | The F<README> file for general stuff.
|
---|
3651 |
|
---|
3652 | The F<Artistic> and F<Copying> files for copyright information.
|
---|
3653 |
|
---|
3654 | =head1 HISTORY
|
---|
3655 |
|
---|
3656 | Written by Gurusamy Sarathy <F<[email protected]>>, with many
|
---|
3657 | contributions from The Perl Porters.
|
---|
3658 |
|
---|
3659 | Send omissions or corrections to <F<[email protected]>>.
|
---|
3660 |
|
---|
3661 | =cut
|
---|