1 | package Time::HiRes;
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2 |
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3 | use strict;
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4 | use vars qw($VERSION $XS_VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD);
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5 |
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6 | require Exporter;
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7 | require DynaLoader;
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8 |
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9 | @ISA = qw(Exporter DynaLoader);
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10 |
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11 | @EXPORT = qw( );
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12 | @EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval
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13 | getitimer setitimer nanosleep clock_gettime clock_getres
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14 | clock clock_nanosleep
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15 | CLOCK_HIGHRES CLOCK_MONOTONIC CLOCK_PROCESS_CPUTIME_ID
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16 | CLOCK_REALTIME CLOCK_SOFTTIME CLOCK_THREAD_CPUTIME_ID
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17 | CLOCK_TIMEOFDAY CLOCKS_PER_SEC
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18 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF
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19 | TIMER_ABSTIME
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20 | d_usleep d_ualarm d_gettimeofday d_getitimer d_setitimer
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21 | d_nanosleep d_clock_gettime d_clock_getres
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22 | d_clock d_clock_nanosleep);
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23 |
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24 | $VERSION = '1.86';
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25 | $XS_VERSION = $VERSION;
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26 | $VERSION = eval $VERSION;
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27 |
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28 | sub AUTOLOAD {
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29 | my $constname;
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30 | ($constname = $AUTOLOAD) =~ s/.*:://;
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31 | # print "AUTOLOAD: constname = $constname ($AUTOLOAD)\n";
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32 | die "&Time::HiRes::constant not defined" if $constname eq 'constant';
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33 | my ($error, $val) = constant($constname);
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34 | # print "AUTOLOAD: error = $error, val = $val\n";
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35 | if ($error) {
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36 | my (undef,$file,$line) = caller;
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37 | die "$error at $file line $line.\n";
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38 | }
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39 | {
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40 | no strict 'refs';
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41 | *$AUTOLOAD = sub { $val };
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42 | }
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43 | goto &$AUTOLOAD;
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44 | }
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45 |
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46 | sub import {
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47 | my $this = shift;
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48 | for my $i (@_) {
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49 | if (($i eq 'clock_getres' && !&d_clock_getres) ||
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50 | ($i eq 'clock_gettime' && !&d_clock_gettime) ||
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51 | ($i eq 'clock_nanosleep' && !&d_clock_nanosleep) ||
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52 | ($i eq 'clock' && !&d_clock) ||
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53 | ($i eq 'nanosleep' && !&d_nanosleep) ||
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54 | ($i eq 'usleep' && !&d_usleep) ||
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55 | ($i eq 'ualarm' && !&d_ualarm)) {
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56 | require Carp;
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57 | Carp::croak("Time::HiRes::$i(): unimplemented in this platform");
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58 | }
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59 | }
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60 | Time::HiRes->export_to_level(1, $this, @_);
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61 | }
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62 |
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63 | bootstrap Time::HiRes;
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64 |
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65 | # Preloaded methods go here.
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66 |
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67 | sub tv_interval {
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68 | # probably could have been done in C
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69 | my ($a, $b) = @_;
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70 | $b = [gettimeofday()] unless defined($b);
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71 | (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000);
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72 | }
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73 |
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74 | # Autoload methods go after =cut, and are processed by the autosplit program.
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75 |
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76 | 1;
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77 | __END__
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78 |
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79 | =head1 NAME
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80 |
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81 | Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers
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82 |
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83 | =head1 SYNOPSIS
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84 |
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85 | use Time::HiRes qw( usleep ualarm gettimeofday tv_interval nanosleep
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86 | clock_gettime clock_getres clock_nanosleep clock );
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87 |
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88 | usleep ($microseconds);
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89 | nanosleep ($nanoseconds);
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90 |
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91 | ualarm ($microseconds);
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92 | ualarm ($microseconds, $interval_microseconds);
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93 |
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94 | $t0 = [gettimeofday];
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95 | ($seconds, $microseconds) = gettimeofday;
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96 |
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97 | $elapsed = tv_interval ( $t0, [$seconds, $microseconds]);
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98 | $elapsed = tv_interval ( $t0, [gettimeofday]);
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99 | $elapsed = tv_interval ( $t0 );
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100 |
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101 | use Time::HiRes qw ( time alarm sleep );
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102 |
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103 | $now_fractions = time;
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104 | sleep ($floating_seconds);
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105 | alarm ($floating_seconds);
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106 | alarm ($floating_seconds, $floating_interval);
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107 |
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108 | use Time::HiRes qw( setitimer getitimer
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109 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF );
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110 |
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111 | setitimer ($which, $floating_seconds, $floating_interval );
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112 | getitimer ($which);
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113 |
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114 | $realtime = clock_gettime(CLOCK_REALTIME);
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115 | $resolution = clock_getres(CLOCK_REALTIME);
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116 |
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117 | clock_nanosleep(CLOCK_REALTIME, 1.5);
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118 | clock_nanosleep(CLOCK_REALTIME, time() + 10, TIMER_ABSTIME);
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119 |
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120 | my $ticktock = clock();
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121 |
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122 | =head1 DESCRIPTION
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123 |
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124 | The C<Time::HiRes> module implements a Perl interface to the
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125 | C<usleep>, C<nanosleep>, C<ualarm>, C<gettimeofday>, and
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126 | C<setitimer>/C<getitimer> system calls, in other words, high
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127 | resolution time and timers. See the L</EXAMPLES> section below and the
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128 | test scripts for usage; see your system documentation for the
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129 | description of the underlying C<nanosleep> or C<usleep>, C<ualarm>,
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130 | C<gettimeofday>, and C<setitimer>/C<getitimer> calls.
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131 |
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132 | If your system lacks C<gettimeofday()> or an emulation of it you don't
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133 | get C<gettimeofday()> or the one-argument form of C<tv_interval()>.
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134 | If your system lacks all of C<nanosleep()>, C<usleep()>,
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135 | C<select()>, and C<poll>, you don't get C<Time::HiRes::usleep()>,
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136 | C<Time::HiRes::nanosleep()>, or C<Time::HiRes::sleep()>.
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137 | If your system lacks both C<ualarm()> and C<setitimer()> you don't get
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138 | C<Time::HiRes::ualarm()> or C<Time::HiRes::alarm()>.
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139 |
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140 | If you try to import an unimplemented function in the C<use> statement
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141 | it will fail at compile time.
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142 |
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143 | If your subsecond sleeping is implemented with C<nanosleep()> instead
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144 | of C<usleep()>, you can mix subsecond sleeping with signals since
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145 | C<nanosleep()> does not use signals. This, however, is not portable,
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146 | and you should first check for the truth value of
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147 | C<&Time::HiRes::d_nanosleep> to see whether you have nanosleep, and
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148 | then carefully read your C<nanosleep()> C API documentation for any
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149 | peculiarities.
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150 |
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151 | If you are using C<nanosleep> for something else than mixing sleeping
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152 | with signals, give some thought to whether Perl is the tool you should
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153 | be using for work requiring nanosecond accuracies.
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154 |
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155 | The following functions can be imported from this module.
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156 | No functions are exported by default.
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157 |
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158 | =over 4
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159 |
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160 | =item gettimeofday ()
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161 |
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162 | In array context returns a two-element array with the seconds and
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163 | microseconds since the epoch. In scalar context returns floating
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164 | seconds like C<Time::HiRes::time()> (see below).
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165 |
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166 | =item usleep ( $useconds )
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167 |
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168 | Sleeps for the number of microseconds (millionths of a second)
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169 | specified. Returns the number of microseconds actually slept. Can
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170 | sleep for more than one second, unlike the C<usleep> system call. Can
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171 | also sleep for zero seconds, which often works like a I<thread yield>.
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172 | See also C<Time::HiRes::usleep()>, C<Time::HiRes::sleep()>, and
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173 | C<Time::HiRes::clock_nanosleep()>.
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174 |
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175 | Do not expect usleep() to be exact down to one microsecond.
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176 |
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177 | =item nanosleep ( $nanoseconds )
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178 |
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179 | Sleeps for the number of nanoseconds (1e9ths of a second) specified.
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180 | Returns the number of nanoseconds actually slept (accurate only to
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181 | microseconds, the nearest thousand of them). Can sleep for more than
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182 | one second. Can also sleep for zero seconds, which often works like a
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183 | I<thread yield>. See also C<Time::HiRes::sleep()>,
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184 | C<Time::HiRes::usleep()>, and C<Time::HiRes::clock_nanosleep()>.
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185 |
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186 | Do not expect nanosleep() to be exact down to one nanosecond.
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187 | Getting even accuracy of one thousand nanoseconds is good.
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188 |
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189 | =item ualarm ( $useconds [, $interval_useconds ] )
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190 |
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191 | Issues a C<ualarm> call; the C<$interval_useconds> is optional and
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192 | will be zero if unspecified, resulting in C<alarm>-like behaviour.
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193 |
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194 | Note that the interaction between alarms and sleeps is unspecified.
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195 |
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196 | =item tv_interval
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197 |
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198 | tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )
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199 |
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200 | Returns the floating seconds between the two times, which should have
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201 | been returned by C<gettimeofday()>. If the second argument is omitted,
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202 | then the current time is used.
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203 |
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204 | =item time ()
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205 |
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206 | Returns a floating seconds since the epoch. This function can be
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207 | imported, resulting in a nice drop-in replacement for the C<time>
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208 | provided with core Perl; see the L</EXAMPLES> below.
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209 |
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210 | B<NOTE 1>: This higher resolution timer can return values either less
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211 | or more than the core C<time()>, depending on whether your platform
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212 | rounds the higher resolution timer values up, down, or to the nearest second
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213 | to get the core C<time()>, but naturally the difference should be never
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214 | more than half a second. See also L</clock_getres>, if available
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215 | in your system.
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216 |
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217 | B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT, when
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218 | the C<time()> seconds since epoch rolled over to 1_000_000_000, the
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219 | default floating point format of Perl and the seconds since epoch have
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220 | conspired to produce an apparent bug: if you print the value of
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221 | C<Time::HiRes::time()> you seem to be getting only five decimals, not
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222 | six as promised (microseconds). Not to worry, the microseconds are
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223 | there (assuming your platform supports such granularity in the first
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224 | place). What is going on is that the default floating point format of
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225 | Perl only outputs 15 digits. In this case that means ten digits
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226 | before the decimal separator and five after. To see the microseconds
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227 | you can use either C<printf>/C<sprintf> with C<"%.6f">, or the
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228 | C<gettimeofday()> function in list context, which will give you the
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229 | seconds and microseconds as two separate values.
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230 |
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231 | =item sleep ( $floating_seconds )
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232 |
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233 | Sleeps for the specified amount of seconds. Returns the number of
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234 | seconds actually slept (a floating point value). This function can
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235 | be imported, resulting in a nice drop-in replacement for the C<sleep>
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236 | provided with perl, see the L</EXAMPLES> below.
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237 |
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238 | Note that the interaction between alarms and sleeps is unspecified.
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239 |
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240 | =item alarm ( $floating_seconds [, $interval_floating_seconds ] )
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241 |
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242 | The C<SIGALRM> signal is sent after the specified number of seconds.
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243 | Implemented using C<ualarm()>. The C<$interval_floating_seconds> argument
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244 | is optional and will be zero if unspecified, resulting in C<alarm()>-like
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245 | behaviour. This function can be imported, resulting in a nice drop-in
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246 | replacement for the C<alarm> provided with perl, see the L</EXAMPLES> below.
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247 |
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248 | B<NOTE 1>: With some combinations of operating systems and Perl
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249 | releases C<SIGALRM> restarts C<select()>, instead of interrupting it.
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250 | This means that an C<alarm()> followed by a C<select()> may together
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251 | take the sum of the times specified for the the C<alarm()> and the
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252 | C<select()>, not just the time of the C<alarm()>.
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253 |
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254 | Note that the interaction between alarms and sleeps is unspecified.
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255 |
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256 | =item setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] )
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257 |
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258 | Start up an interval timer: after a certain time, a signal arrives,
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259 | and more signals may keep arriving at certain intervals. To disable
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260 | an "itimer", use C<$floating_seconds> of zero. If the
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261 | C<$interval_floating_seconds> is set to zero (or unspecified), the
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262 | timer is disabled B<after> the next delivered signal.
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263 |
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264 | Use of interval timers may interfere with C<alarm()>, C<sleep()>,
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265 | and C<usleep()>. In standard-speak the "interaction is unspecified",
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266 | which means that I<anything> may happen: it may work, it may not.
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267 |
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268 | In scalar context, the remaining time in the timer is returned.
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269 |
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270 | In list context, both the remaining time and the interval are returned.
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271 |
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272 | There are usually three or four interval timers available: the
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273 | C<$which> can be C<ITIMER_REAL>, C<ITIMER_VIRTUAL>, C<ITIMER_PROF>, or
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274 | C<ITIMER_REALPROF>. Note that which ones are available depends: true
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275 | UNIX platforms usually have the first three, but (for example) Win32
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276 | and Cygwin have only C<ITIMER_REAL>, and only Solaris seems to have
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277 | C<ITIMER_REALPROF> (which is used to profile multithreaded programs).
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278 |
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279 | C<ITIMER_REAL> results in C<alarm()>-like behaviour. Time is counted in
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280 | I<real time>; that is, wallclock time. C<SIGALRM> is delivered when
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281 | the timer expires.
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282 |
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283 | C<ITIMER_VIRTUAL> counts time in (process) I<virtual time>; that is,
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284 | only when the process is running. In multiprocessor/user/CPU systems
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285 | this may be more or less than real or wallclock time. (This time is
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286 | also known as the I<user time>.) C<SIGVTALRM> is delivered when the
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287 | timer expires.
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288 |
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289 | C<ITIMER_PROF> counts time when either the process virtual time or when
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290 | the operating system is running on behalf of the process (such as I/O).
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291 | (This time is also known as the I<system time>.) (The sum of user
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292 | time and system time is known as the I<CPU time>.) C<SIGPROF> is
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293 | delivered when the timer expires. C<SIGPROF> can interrupt system calls.
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294 |
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295 | The semantics of interval timers for multithreaded programs are
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296 | system-specific, and some systems may support additional interval
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297 | timers. See your C<setitimer()> documentation.
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298 |
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299 | =item getitimer ( $which )
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300 |
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301 | Return the remaining time in the interval timer specified by C<$which>.
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302 |
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303 | In scalar context, the remaining time is returned.
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304 |
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305 | In list context, both the remaining time and the interval are returned.
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306 | The interval is always what you put in using C<setitimer()>.
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307 |
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308 | =item clock_gettime ( $which )
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309 |
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310 | Return as seconds the current value of the POSIX high resolution timer
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311 | specified by C<$which>. All implementations that support POSIX high
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312 | resolution timers are supposed to support at least the C<$which> value
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313 | of C<CLOCK_REALTIME>, which is supposed to return results close to the
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314 | results of C<gettimeofday>, or the number of seconds since 00:00:00:00
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315 | January 1, 1970 Greenwich Mean Time (GMT). Do not assume that
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316 | CLOCK_REALTIME is zero, it might be one, or something else.
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317 | Another potentially useful (but not available everywhere) value is
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318 | C<CLOCK_MONOTONIC>, which guarantees a monotonically increasing time
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319 | value (unlike time(), which can be adjusted). See your system
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320 | documentation for other possibly supported values.
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321 |
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322 | =item clock_getres ( $which )
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323 |
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324 | Return as seconds the resolution of the POSIX high resolution timer
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325 | specified by C<$which>. All implementations that support POSIX high
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326 | resolution timers are supposed to support at least the C<$which> value
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327 | of C<CLOCK_REALTIME>, see L</clock_gettime>.
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328 |
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329 | =item clock_nanosleep ( $which, $seconds, $flags = 0)
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330 |
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331 | Sleeps for the number of seconds (1e9ths of a second) specified.
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332 | Returns the number of seconds actually slept. The $which is the
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333 | "clock id", as with clock_gettime() and clock_getres(). The flags
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334 | default to zero but C<TIMER_ABSTIME> can specified (must be exported
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335 | explicitly) which means that C<$nanoseconds> is not a time interval
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336 | (as is the default) but instead an absolute time. Can sleep for more
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337 | than one second. Can also sleep for zero seconds, which often works
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338 | like a I<thread yield>. See also C<Time::HiRes::sleep()>,
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339 | C<Time::HiRes::usleep()>, and C<Time::HiRes::nanosleep()>.
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340 |
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341 | Do not expect clock_nanosleep() to be exact down to one nanosecond.
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342 | Getting even accuracy of one thousand nanoseconds is good.
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343 |
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344 | =item clock()
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345 |
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346 | Return as seconds the I<process time> (user + system time) spent by
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347 | the process since the first call to clock() (the definition is B<not>
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348 | "since the start of the process", though if you are lucky these times
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349 | may be quite close to each other, depending on the system). What this
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350 | means is that you probably need to store the result of your first call
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351 | to clock(), and subtract that value from the following results of clock().
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352 |
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353 | The time returned also includes the process times of the terminated
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354 | child processes for which wait() has been executed. This value is
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355 | somewhat like the second value returned by the times() of core Perl,
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356 | but not necessarily identical. Note that due to backward
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357 | compatibility limitations the returned value may wrap around at about
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358 | 2147 seconds or at about 36 minutes.
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359 |
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360 | =back
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361 |
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362 | =head1 EXAMPLES
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363 |
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364 | use Time::HiRes qw(usleep ualarm gettimeofday tv_interval);
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365 |
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366 | $microseconds = 750_000;
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367 | usleep($microseconds);
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368 |
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369 | # signal alarm in 2.5s & every .1s thereafter
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370 | ualarm(2_500_000, 100_000);
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371 |
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372 | # get seconds and microseconds since the epoch
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373 | ($s, $usec) = gettimeofday();
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374 |
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375 | # measure elapsed time
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376 | # (could also do by subtracting 2 gettimeofday return values)
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377 | $t0 = [gettimeofday];
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378 | # do bunch of stuff here
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379 | $t1 = [gettimeofday];
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380 | # do more stuff here
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381 | $t0_t1 = tv_interval $t0, $t1;
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382 |
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383 | $elapsed = tv_interval ($t0, [gettimeofday]);
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384 | $elapsed = tv_interval ($t0); # equivalent code
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385 |
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386 | #
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387 | # replacements for time, alarm and sleep that know about
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388 | # floating seconds
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389 | #
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390 | use Time::HiRes;
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391 | $now_fractions = Time::HiRes::time;
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392 | Time::HiRes::sleep (2.5);
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393 | Time::HiRes::alarm (10.6666666);
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394 |
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395 | use Time::HiRes qw ( time alarm sleep );
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396 | $now_fractions = time;
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397 | sleep (2.5);
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398 | alarm (10.6666666);
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399 |
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400 | # Arm an interval timer to go off first at 10 seconds and
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401 | # after that every 2.5 seconds, in process virtual time
|
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402 |
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403 | use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time );
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404 |
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405 | $SIG{VTALRM} = sub { print time, "\n" };
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406 | setitimer(ITIMER_VIRTUAL, 10, 2.5);
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407 |
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408 | use Time::HiRes qw( clock_gettime clock_getres CLOCK_REALTIME );
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409 | # Read the POSIX high resolution timer.
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410 | my $high = clock_getres(CLOCK_REALTIME);
|
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411 | # But how accurate we can be, really?
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412 | my $reso = clock_getres(CLOCK_REALTIME);
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413 |
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414 | use Time::HiRes qw( clock_nanosleep TIMER_ABSTIME );
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415 | clock_nanosleep(CLOCK_REALTIME, 1e6);
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416 | clock_nanosleep(CLOCK_REALTIME, 2e9, TIMER_ABSTIME);
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417 |
|
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418 | use Time::HiRes qw( clock );
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419 | my $clock0 = clock();
|
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420 | ... # Do something.
|
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421 | my $clock1 = clock();
|
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422 | my $clockd = $clock1 - $clock0;
|
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423 |
|
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424 | =head1 C API
|
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425 |
|
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426 | In addition to the perl API described above, a C API is available for
|
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427 | extension writers. The following C functions are available in the
|
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428 | modglobal hash:
|
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429 |
|
---|
430 | name C prototype
|
---|
431 | --------------- ----------------------
|
---|
432 | Time::NVtime double (*)()
|
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433 | Time::U2time void (*)(pTHX_ UV ret[2])
|
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434 |
|
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435 | Both functions return equivalent information (like C<gettimeofday>)
|
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436 | but with different representations. The names C<NVtime> and C<U2time>
|
---|
437 | were selected mainly because they are operating system independent.
|
---|
438 | (C<gettimeofday> is Unix-centric, though some platforms like Win32 and
|
---|
439 | VMS have emulations for it.)
|
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440 |
|
---|
441 | Here is an example of using C<NVtime> from C:
|
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442 |
|
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443 | double (*myNVtime)(); /* Returns -1 on failure. */
|
---|
444 | SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0);
|
---|
445 | if (!svp) croak("Time::HiRes is required");
|
---|
446 | if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer");
|
---|
447 | myNVtime = INT2PTR(double(*)(), SvIV(*svp));
|
---|
448 | printf("The current time is: %f\n", (*myNVtime)());
|
---|
449 |
|
---|
450 | =head1 DIAGNOSTICS
|
---|
451 |
|
---|
452 | =head2 negative time not invented yet
|
---|
453 |
|
---|
454 | You tried to use a negative time argument.
|
---|
455 |
|
---|
456 | =head2 internal error: useconds < 0 (unsigned ... signed ...)
|
---|
457 |
|
---|
458 | Something went horribly wrong-- the number of microseconds that cannot
|
---|
459 | become negative just became negative. Maybe your compiler is broken?
|
---|
460 |
|
---|
461 | =head1 CAVEATS
|
---|
462 |
|
---|
463 | Notice that the core C<time()> maybe rounding rather than truncating.
|
---|
464 | What this means is that the core C<time()> may be reporting the time
|
---|
465 | as one second later than C<gettimeofday()> and C<Time::HiRes::time()>.
|
---|
466 |
|
---|
467 | Adjusting the system clock (either manually or by services like ntp)
|
---|
468 | may cause problems, especially for long running programs that assume
|
---|
469 | a monotonously increasing time (note that all platforms do not adjust
|
---|
470 | time as gracefully as UNIX ntp does). For example in Win32 (and derived
|
---|
471 | platforms like Cygwin and MinGW) the Time::HiRes::time() may temporarily
|
---|
472 | drift off from the system clock (and the original time()) by up to 0.5
|
---|
473 | seconds. Time::HiRes will notice this eventually and recalibrate.
|
---|
474 | Note that since Time::HiRes 1.77 the clock_gettime(CLOCK_MONOTONIC)
|
---|
475 | might help in this (in case your system supports CLOCK_MONOTONIC).
|
---|
476 |
|
---|
477 | =head1 SEE ALSO
|
---|
478 |
|
---|
479 | Perl modules L<BSD::Resource>, L<Time::TAI64>.
|
---|
480 |
|
---|
481 | Your system documentation for C<clock_gettime>, C<clock_settime>,
|
---|
482 | C<gettimeofday>, C<getitimer>, C<setitimer>, C<ualarm>.
|
---|
483 |
|
---|
484 | =head1 AUTHORS
|
---|
485 |
|
---|
486 | D. Wegscheid <[email protected]>
|
---|
487 | R. Schertler <[email protected]>
|
---|
488 | J. Hietaniemi <[email protected]>
|
---|
489 | G. Aas <[email protected]>
|
---|
490 |
|
---|
491 | =head1 COPYRIGHT AND LICENSE
|
---|
492 |
|
---|
493 | Copyright (c) 1996-2002 Douglas E. Wegscheid. All rights reserved.
|
---|
494 |
|
---|
495 | Copyright (c) 2002, 2003, 2004, 2005 Jarkko Hietaniemi. All rights reserved.
|
---|
496 |
|
---|
497 | This program is free software; you can redistribute it and/or modify
|
---|
498 | it under the same terms as Perl itself.
|
---|
499 |
|
---|
500 | =cut
|
---|