1 | # IO::Pipe.pm
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2 | #
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3 | # Copyright (c) 1996-8 Graham Barr <[email protected]>. All rights reserved.
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4 | # This program is free software; you can redistribute it and/or
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5 | # modify it under the same terms as Perl itself.
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6 |
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7 | package IO::Pipe;
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8 |
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9 | use 5.006_001;
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10 |
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11 | use IO::Handle;
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12 | use strict;
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13 | our($VERSION);
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14 | use Carp;
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15 | use Symbol;
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16 |
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17 | $VERSION = "1.13";
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18 |
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19 | sub new {
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20 | my $type = shift;
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21 | my $class = ref($type) || $type || "IO::Pipe";
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22 | @_ == 0 || @_ == 2 or croak "usage: new $class [READFH, WRITEFH]";
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23 |
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24 | my $me = bless gensym(), $class;
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25 |
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26 | my($readfh,$writefh) = @_ ? @_ : $me->handles;
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27 |
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28 | pipe($readfh, $writefh)
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29 | or return undef;
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30 |
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31 | @{*$me} = ($readfh, $writefh);
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32 |
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33 | $me;
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34 | }
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35 |
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36 | sub handles {
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37 | @_ == 1 or croak 'usage: $pipe->handles()';
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38 | (IO::Pipe::End->new(), IO::Pipe::End->new());
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39 | }
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40 |
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41 | my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32';
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42 |
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43 | sub _doit {
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44 | my $me = shift;
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45 | my $rw = shift;
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46 |
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47 | my $pid = $do_spawn ? 0 : fork();
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48 |
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49 | if($pid) { # Parent
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50 | return $pid;
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51 | }
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52 | elsif(defined $pid) { # Child or spawn
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53 | my $fh;
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54 | my $io = $rw ? \*STDIN : \*STDOUT;
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55 | my ($mode, $save) = $rw ? "r" : "w";
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56 | if ($do_spawn) {
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57 | require Fcntl;
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58 | $save = IO::Handle->new_from_fd($io, $mode);
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59 | my $handle = shift;
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60 | # Close in child:
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61 | unless ($^O eq 'MSWin32') {
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62 | fcntl($handle, Fcntl::F_SETFD(), 1) or croak "fcntl: $!";
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63 | }
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64 | $fh = $rw ? ${*$me}[0] : ${*$me}[1];
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65 | } else {
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66 | shift;
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67 | $fh = $rw ? $me->reader() : $me->writer(); # close the other end
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68 | }
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69 | bless $io, "IO::Handle";
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70 | $io->fdopen($fh, $mode);
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71 | $fh->close;
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72 |
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73 | if ($do_spawn) {
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74 | $pid = eval { system 1, @_ }; # 1 == P_NOWAIT
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75 | my $err = $!;
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76 |
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77 | $io->fdopen($save, $mode);
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78 | $save->close or croak "Cannot close $!";
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79 | croak "IO::Pipe: Cannot spawn-NOWAIT: $err" if not $pid or $pid < 0;
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80 | return $pid;
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81 | } else {
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82 | exec @_ or
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83 | croak "IO::Pipe: Cannot exec: $!";
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84 | }
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85 | }
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86 | else {
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87 | croak "IO::Pipe: Cannot fork: $!";
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88 | }
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89 |
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90 | # NOT Reached
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91 | }
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92 |
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93 | sub reader {
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94 | @_ >= 1 or croak 'usage: $pipe->reader( [SUB_COMMAND_ARGS] )';
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95 | my $me = shift;
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96 |
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97 | return undef
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98 | unless(ref($me) || ref($me = $me->new));
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99 |
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100 | my $fh = ${*$me}[0];
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101 | my $pid;
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102 | $pid = $me->_doit(0, $fh, @_)
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103 | if(@_);
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104 |
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105 | close ${*$me}[1];
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106 | bless $me, ref($fh);
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107 | *$me = *$fh; # Alias self to handle
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108 | $me->fdopen($fh->fileno,"r")
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109 | unless defined($me->fileno);
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110 | bless $fh; # Really wan't un-bless here
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111 | ${*$me}{'io_pipe_pid'} = $pid
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112 | if defined $pid;
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113 |
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114 | $me;
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115 | }
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116 |
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117 | sub writer {
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118 | @_ >= 1 or croak 'usage: $pipe->writer( [SUB_COMMAND_ARGS] )';
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119 | my $me = shift;
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120 |
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121 | return undef
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122 | unless(ref($me) || ref($me = $me->new));
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123 |
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124 | my $fh = ${*$me}[1];
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125 | my $pid;
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126 | $pid = $me->_doit(1, $fh, @_)
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127 | if(@_);
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128 |
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129 | close ${*$me}[0];
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130 | bless $me, ref($fh);
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131 | *$me = *$fh; # Alias self to handle
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132 | $me->fdopen($fh->fileno,"w")
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133 | unless defined($me->fileno);
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134 | bless $fh; # Really wan't un-bless here
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135 | ${*$me}{'io_pipe_pid'} = $pid
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136 | if defined $pid;
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137 |
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138 | $me;
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139 | }
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140 |
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141 | package IO::Pipe::End;
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142 |
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143 | our(@ISA);
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144 |
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145 | @ISA = qw(IO::Handle);
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146 |
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147 | sub close {
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148 | my $fh = shift;
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149 | my $r = $fh->SUPER::close(@_);
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150 |
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151 | waitpid(${*$fh}{'io_pipe_pid'},0)
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152 | if(defined ${*$fh}{'io_pipe_pid'});
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153 |
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154 | $r;
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155 | }
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156 |
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157 | 1;
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158 |
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159 | __END__
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160 |
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161 | =head1 NAME
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162 |
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163 | IO::Pipe - supply object methods for pipes
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164 |
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165 | =head1 SYNOPSIS
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166 |
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167 | use IO::Pipe;
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168 |
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169 | $pipe = new IO::Pipe;
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170 |
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171 | if($pid = fork()) { # Parent
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172 | $pipe->reader();
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173 |
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174 | while(<$pipe>) {
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175 | ...
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176 | }
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177 |
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178 | }
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179 | elsif(defined $pid) { # Child
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180 | $pipe->writer();
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181 |
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182 | print $pipe ...
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183 | }
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184 |
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185 | or
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186 |
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187 | $pipe = new IO::Pipe;
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188 |
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189 | $pipe->reader(qw(ls -l));
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190 |
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191 | while(<$pipe>) {
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192 | ...
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193 | }
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194 |
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195 | =head1 DESCRIPTION
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196 |
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197 | C<IO::Pipe> provides an interface to creating pipes between
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198 | processes.
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199 |
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200 | =head1 CONSTRUCTOR
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201 |
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202 | =over 4
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203 |
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204 | =item new ( [READER, WRITER] )
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205 |
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206 | Creates an C<IO::Pipe>, which is a reference to a newly created symbol
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207 | (see the C<Symbol> package). C<IO::Pipe::new> optionally takes two
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208 | arguments, which should be objects blessed into C<IO::Handle>, or a
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209 | subclass thereof. These two objects will be used for the system call
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210 | to C<pipe>. If no arguments are given then method C<handles> is called
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211 | on the new C<IO::Pipe> object.
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212 |
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213 | These two handles are held in the array part of the GLOB until either
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214 | C<reader> or C<writer> is called.
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215 |
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216 | =back
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217 |
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218 | =head1 METHODS
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219 |
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220 | =over 4
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221 |
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222 | =item reader ([ARGS])
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223 |
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224 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a
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225 | handle at the reading end of the pipe. If C<ARGS> are given then C<fork>
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226 | is called and C<ARGS> are passed to exec.
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227 |
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228 | =item writer ([ARGS])
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229 |
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230 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a
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231 | handle at the writing end of the pipe. If C<ARGS> are given then C<fork>
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232 | is called and C<ARGS> are passed to exec.
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233 |
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234 | =item handles ()
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235 |
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236 | This method is called during construction by C<IO::Pipe::new>
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237 | on the newly created C<IO::Pipe> object. It returns an array of two objects
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238 | blessed into C<IO::Pipe::End>, or a subclass thereof.
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239 |
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240 | =back
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241 |
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242 | =head1 SEE ALSO
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243 |
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244 | L<IO::Handle>
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245 |
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246 | =head1 AUTHOR
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247 |
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248 | Graham Barr. Currently maintained by the Perl Porters. Please report all
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249 | bugs to <[email protected]>.
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250 |
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251 | =head1 COPYRIGHT
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252 |
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253 | Copyright (c) 1996-8 Graham Barr <[email protected]>. All rights reserved.
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254 | This program is free software; you can redistribute it and/or
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255 | modify it under the same terms as Perl itself.
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256 |
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257 | =cut
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