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dcf686c9 |
1 | package Time::HiRes; |
2 | |
3 | use strict; |
105cd853 |
4 | use vars qw($VERSION $XS_VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD); |
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5 | |
6 | require Exporter; |
3f2ee006 |
7 | require DynaLoader; |
dcf686c9 |
8 | |
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9 | @ISA = qw(Exporter DynaLoader); |
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10 | |
11 | @EXPORT = qw( ); |
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12 | @EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval |
ced84e60 |
13 | getitimer setitimer nanosleep clock_gettime clock_getres |
14 | CLOCK_HIGHRES CLOCK_MONOTONIC CLOCK_PROCESS_CPUTIME_ID |
15 | CLOCK_REALTIME CLOCK_THREAD_CPUTIME_ID CLOCK_TIMEOFDAY |
3f2ee006 |
16 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF |
17 | d_usleep d_ualarm d_gettimeofday d_getitimer d_setitimer |
ced84e60 |
18 | d_nanosleep d_clock_gettime d_clock_getres); |
3f2ee006 |
19 | |
b311af62 |
20 | $VERSION = '1.81'; |
105cd853 |
21 | $XS_VERSION = $VERSION; |
22 | $VERSION = eval $VERSION; |
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23 | |
24 | sub AUTOLOAD { |
25 | my $constname; |
98b50af3 |
26 | ($constname = $AUTOLOAD) =~ s/.*:://; |
ced84e60 |
27 | # print "AUTOLOAD: constname = $constname ($AUTOLOAD)\n"; |
98b50af3 |
28 | die "&Time::HiRes::constant not defined" if $constname eq 'constant'; |
29 | my ($error, $val) = constant($constname); |
ced84e60 |
30 | # print "AUTOLOAD: error = $error, val = $val\n"; |
0cf8ddea |
31 | if ($error) { |
32 | my (undef,$file,$line) = caller; |
33 | die "$error at $file line $line.\n"; |
34 | } |
3c72ec00 |
35 | { |
36 | no strict 'refs'; |
37 | *$AUTOLOAD = sub { $val }; |
38 | } |
39 | goto &$AUTOLOAD; |
40 | } |
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41 | |
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42 | sub import { |
43 | my $this = shift; |
44 | for my $i (@_) { |
45 | if (($i eq 'clock_getres' && !&d_clock_getres) || |
46 | ($i eq 'clock_gettime' && !&d_clock_gettime) || |
47 | ($i eq 'nanosleep' && !&d_nanosleep) || |
48 | ($i eq 'usleep' && !&d_usleep) || |
49 | ($i eq 'ualarm' && !&d_ualarm)) { |
50 | require Carp; |
51 | Carp::croak("Time::HiRes::$i(): unimplemented in this platform"); |
52 | } |
53 | } |
54 | Time::HiRes->export_to_level(1, $this, @_); |
55 | } |
56 | |
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57 | bootstrap Time::HiRes; |
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58 | |
59 | # Preloaded methods go here. |
60 | |
61 | sub tv_interval { |
62 | # probably could have been done in C |
63 | my ($a, $b) = @_; |
64 | $b = [gettimeofday()] unless defined($b); |
65 | (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000); |
66 | } |
67 | |
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68 | # Autoload methods go after =cut, and are processed by the autosplit program. |
69 | |
70 | 1; |
71 | __END__ |
72 | |
73 | =head1 NAME |
74 | |
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75 | Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers |
dcf686c9 |
76 | |
77 | =head1 SYNOPSIS |
78 | |
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79 | use Time::HiRes qw( usleep ualarm gettimeofday tv_interval nanosleep |
80 | clock_gettime clock_getres ); |
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81 | |
82 | usleep ($microseconds); |
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83 | nanosleep ($nanoseconds); |
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84 | |
85 | ualarm ($microseconds); |
86 | ualarm ($microseconds, $interval_microseconds); |
87 | |
88 | $t0 = [gettimeofday]; |
89 | ($seconds, $microseconds) = gettimeofday; |
90 | |
91 | $elapsed = tv_interval ( $t0, [$seconds, $microseconds]); |
92 | $elapsed = tv_interval ( $t0, [gettimeofday]); |
93 | $elapsed = tv_interval ( $t0 ); |
94 | |
95 | use Time::HiRes qw ( time alarm sleep ); |
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96 | |
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97 | $now_fractions = time; |
98 | sleep ($floating_seconds); |
99 | alarm ($floating_seconds); |
100 | alarm ($floating_seconds, $floating_interval); |
101 | |
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102 | use Time::HiRes qw( setitimer getitimer |
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103 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF ); |
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104 | |
105 | setitimer ($which, $floating_seconds, $floating_interval ); |
106 | getitimer ($which); |
107 | |
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108 | $realtime = clock_gettime(CLOCK_REALTIME); |
109 | |
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110 | =head1 DESCRIPTION |
111 | |
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112 | The C<Time::HiRes> module implements a Perl interface to the |
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113 | C<usleep>, C<nanosleep>, C<ualarm>, C<gettimeofday>, and |
114 | C<setitimer>/C<getitimer> system calls, in other words, high |
115 | resolution time and timers. See the L</EXAMPLES> section below and the |
116 | test scripts for usage; see your system documentation for the |
117 | description of the underlying C<nanosleep> or C<usleep>, C<ualarm>, |
118 | C<gettimeofday>, and C<setitimer>/C<getitimer> calls. |
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119 | |
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120 | If your system lacks C<gettimeofday()> or an emulation of it you don't |
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121 | get C<gettimeofday()> or the one-argument form of C<tv_interval()>. |
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122 | If your system lacks all of C<nanosleep()>, C<usleep()>, C<select()>, |
123 | and C<poll()>, you don't get C<Time::HiRes::usleep()>, |
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124 | C<Time::HiRes::nanosleep()>, or C<Time::HiRes::sleep()>. If your |
125 | system lacks both C<ualarm()> and C<setitimer()> you don't get |
126 | C<Time::HiRes::ualarm()> or C<Time::HiRes::alarm()>. |
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127 | |
128 | If you try to import an unimplemented function in the C<use> statement |
129 | it will fail at compile time. |
130 | |
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131 | If your subsecond sleeping is implemented with C<nanosleep()> instead |
132 | of C<usleep()>, you can mix subsecond sleeping with signals since |
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133 | C<nanosleep()> does not use signals. This, however, is not portable, |
134 | and you should first check for the truth value of |
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135 | C<&Time::HiRes::d_nanosleep> to see whether you have nanosleep, and |
136 | then carefully read your C<nanosleep()> C API documentation for any |
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137 | peculiarities. |
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138 | |
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139 | If you are using C<nanosleep> for something else than mixing sleeping |
140 | with signals, give some thought to whether Perl is the tool you should |
141 | be using for work requiring nanosecond accuracies. |
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142 | |
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143 | The following functions can be imported from this module. |
144 | No functions are exported by default. |
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145 | |
146 | =over 4 |
147 | |
148 | =item gettimeofday () |
149 | |
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150 | In array context returns a two-element array with the seconds and |
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151 | microseconds since the epoch. In scalar context returns floating |
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152 | seconds like C<Time::HiRes::time()> (see below). |
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153 | |
154 | =item usleep ( $useconds ) |
155 | |
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156 | Sleeps for the number of microseconds (millionths of a second) |
157 | specified. Returns the number of microseconds actually slept. Can |
158 | sleep for more than one second, unlike the C<usleep> system call. See |
159 | also C<Time::HiRes::usleep()> and C<Time::HiRes::sleep()>. |
160 | |
161 | Do not expect usleep() to be exact down to one microsecond. |
162 | |
163 | =item nanosleep ( $nanoseconds ) |
164 | |
165 | Sleeps for the number of nanoseconds (1e9ths of a second) specified. |
166 | Returns the number of nanoseconds actually slept (accurate only to |
167 | microseconds, the nearest thousand of them). Can sleep for more than |
168 | one second. See also C<Time::HiRes::sleep()> and |
169 | C<Time::HiRes::usleep()>. |
170 | |
171 | Do not expect nanosleep() to be exact down to one nanosecond. |
172 | Getting even accuracy of one thousand nanoseconds is good. |
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173 | |
174 | =item ualarm ( $useconds [, $interval_useconds ] ) |
175 | |
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176 | Issues a C<ualarm> call; the C<$interval_useconds> is optional and |
177 | will be zero if unspecified, resulting in C<alarm>-like behaviour. |
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178 | |
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179 | Note that the interaction between alarms and sleeps is unspecified. |
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180 | |
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181 | =item tv_interval |
182 | |
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183 | tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] ) |
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184 | |
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185 | Returns the floating seconds between the two times, which should have |
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186 | been returned by C<gettimeofday()>. If the second argument is omitted, |
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187 | then the current time is used. |
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188 | |
189 | =item time () |
190 | |
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191 | Returns a floating seconds since the epoch. This function can be |
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192 | imported, resulting in a nice drop-in replacement for the C<time> |
193 | provided with core Perl; see the L</EXAMPLES> below. |
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194 | |
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195 | B<NOTE 1>: This higher resolution timer can return values either less |
196 | or more than the core C<time()>, depending on whether your platform |
197 | rounds the higher resolution timer values up, down, or to the nearest second |
198 | to get the core C<time()>, but naturally the difference should be never |
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199 | more than half a second. See also L</clock_getres>, if available |
200 | in your system. |
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201 | |
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202 | B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT, when |
203 | the C<time()> seconds since epoch rolled over to 1_000_000_000, the |
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204 | default floating point format of Perl and the seconds since epoch have |
205 | conspired to produce an apparent bug: if you print the value of |
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206 | C<Time::HiRes::time()> you seem to be getting only five decimals, not |
207 | six as promised (microseconds). Not to worry, the microseconds are |
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208 | there (assuming your platform supports such granularity in the first |
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209 | place). What is going on is that the default floating point format of |
210 | Perl only outputs 15 digits. In this case that means ten digits |
211 | before the decimal separator and five after. To see the microseconds |
212 | you can use either C<printf>/C<sprintf> with C<"%.6f">, or the |
213 | C<gettimeofday()> function in list context, which will give you the |
214 | seconds and microseconds as two separate values. |
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215 | |
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216 | =item sleep ( $floating_seconds ) |
217 | |
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218 | Sleeps for the specified amount of seconds. Returns the number of |
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219 | seconds actually slept (a floating point value). This function can |
220 | be imported, resulting in a nice drop-in replacement for the C<sleep> |
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221 | provided with perl, see the L</EXAMPLES> below. |
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222 | |
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223 | Note that the interaction between alarms and sleeps is unspecified. |
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224 | |
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225 | =item alarm ( $floating_seconds [, $interval_floating_seconds ] ) |
226 | |
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227 | The C<SIGALRM> signal is sent after the specified number of seconds. |
228 | Implemented using C<ualarm()>. The C<$interval_floating_seconds> argument |
229 | is optional and will be zero if unspecified, resulting in C<alarm()>-like |
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230 | behaviour. This function can be imported, resulting in a nice drop-in |
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231 | replacement for the C<alarm> provided with perl, see the L</EXAMPLES> below. |
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232 | |
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233 | B<NOTE 1>: With some combinations of operating systems and Perl |
234 | releases C<SIGALRM> restarts C<select()>, instead of interrupting it. |
235 | This means that an C<alarm()> followed by a C<select()> may together |
236 | take the sum of the times specified for the the C<alarm()> and the |
237 | C<select()>, not just the time of the C<alarm()>. |
238 | |
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239 | Note that the interaction between alarms and sleeps is unspecified. |
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240 | |
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241 | =item setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] ) |
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242 | |
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243 | Start up an interval timer: after a certain time, a signal arrives, |
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244 | and more signals may keep arriving at certain intervals. To disable |
245 | an "itimer", use C<$floating_seconds> of zero. If the |
246 | C<$interval_floating_seconds> is set to zero (or unspecified), the |
247 | timer is disabled B<after> the next delivered signal. |
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248 | |
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249 | Use of interval timers may interfere with C<alarm()>, C<sleep()>, |
250 | and C<usleep()>. In standard-speak the "interaction is unspecified", |
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251 | which means that I<anything> may happen: it may work, it may not. |
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252 | |
253 | In scalar context, the remaining time in the timer is returned. |
254 | |
255 | In list context, both the remaining time and the interval are returned. |
256 | |
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257 | There are usually three or four interval timers available: the |
258 | C<$which> can be C<ITIMER_REAL>, C<ITIMER_VIRTUAL>, C<ITIMER_PROF>, or |
259 | C<ITIMER_REALPROF>. Note that which ones are available depends: true |
260 | UNIX platforms usually have the first three, but (for example) Win32 |
261 | and Cygwin have only C<ITIMER_REAL>, and only Solaris seems to have |
262 | C<ITIMER_REALPROF> (which is used to profile multithreaded programs). |
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263 | |
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264 | C<ITIMER_REAL> results in C<alarm()>-like behaviour. Time is counted in |
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265 | I<real time>; that is, wallclock time. C<SIGALRM> is delivered when |
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266 | the timer expires. |
267 | |
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268 | C<ITIMER_VIRTUAL> counts time in (process) I<virtual time>; that is, |
269 | only when the process is running. In multiprocessor/user/CPU systems |
270 | this may be more or less than real or wallclock time. (This time is |
271 | also known as the I<user time>.) C<SIGVTALRM> is delivered when the |
272 | timer expires. |
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273 | |
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274 | C<ITIMER_PROF> counts time when either the process virtual time or when |
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275 | the operating system is running on behalf of the process (such as I/O). |
276 | (This time is also known as the I<system time>.) (The sum of user |
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277 | time and system time is known as the I<CPU time>.) C<SIGPROF> is |
278 | delivered when the timer expires. C<SIGPROF> can interrupt system calls. |
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279 | |
280 | The semantics of interval timers for multithreaded programs are |
281 | system-specific, and some systems may support additional interval |
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282 | timers. See your C<setitimer()> documentation. |
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283 | |
284 | =item getitimer ( $which ) |
285 | |
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286 | Return the remaining time in the interval timer specified by C<$which>. |
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287 | |
288 | In scalar context, the remaining time is returned. |
289 | |
290 | In list context, both the remaining time and the interval are returned. |
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291 | The interval is always what you put in using C<setitimer()>. |
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292 | |
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293 | =item clock_gettime ( $which ) |
294 | |
295 | Return as seconds the current value of the POSIX high resolution timer |
296 | specified by C<$which>. All implementations that support POSIX high |
297 | resolution timers are supposed to support at least the C<$which> value |
298 | of C<CLOCK_REALTIME>, which is supposed to return results close to the |
299 | results of C<gettimeofday>, or the number of seconds since 00:00:00:00 |
300 | January 1, 1970 Greenwich Mean Time (GMT). Do not assume that |
301 | CLOCK_REALTIME is zero, it might be one, or something else. |
302 | Another potentially useful (but not available everywhere) value is |
303 | C<CLOCK_MONOTONIC>, which guarantees a monotonically increasing time |
304 | value (unlike time(), which can be adjusted). See your system |
305 | documentation for other possibly supported values. |
306 | |
307 | =item clock_getres ( $which ) |
308 | |
309 | Return as seconds the resolution of the POSIX high resolution timer |
310 | specified by C<$which>. All implementations that support POSIX high |
311 | resolution timers are supposed to support at least the C<$which> value |
312 | of C<CLOCK_REALTIME>, see L</clock_gettime>. |
313 | |
dcf686c9 |
314 | =back |
315 | |
316 | =head1 EXAMPLES |
317 | |
318 | use Time::HiRes qw(usleep ualarm gettimeofday tv_interval); |
319 | |
320 | $microseconds = 750_000; |
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321 | usleep($microseconds); |
dcf686c9 |
322 | |
323 | # signal alarm in 2.5s & every .1s thereafter |
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324 | ualarm(2_500_000, 100_000); |
dcf686c9 |
325 | |
326 | # get seconds and microseconds since the epoch |
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327 | ($s, $usec) = gettimeofday(); |
dcf686c9 |
328 | |
329 | # measure elapsed time |
330 | # (could also do by subtracting 2 gettimeofday return values) |
331 | $t0 = [gettimeofday]; |
332 | # do bunch of stuff here |
333 | $t1 = [gettimeofday]; |
334 | # do more stuff here |
335 | $t0_t1 = tv_interval $t0, $t1; |
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336 | |
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337 | $elapsed = tv_interval ($t0, [gettimeofday]); |
338 | $elapsed = tv_interval ($t0); # equivalent code |
339 | |
340 | # |
341 | # replacements for time, alarm and sleep that know about |
342 | # floating seconds |
343 | # |
344 | use Time::HiRes; |
345 | $now_fractions = Time::HiRes::time; |
346 | Time::HiRes::sleep (2.5); |
347 | Time::HiRes::alarm (10.6666666); |
0be47ac6 |
348 | |
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349 | use Time::HiRes qw ( time alarm sleep ); |
350 | $now_fractions = time; |
351 | sleep (2.5); |
352 | alarm (10.6666666); |
353 | |
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354 | # Arm an interval timer to go off first at 10 seconds and |
355 | # after that every 2.5 seconds, in process virtual time |
356 | |
357 | use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time ); |
358 | |
36d6c396 |
359 | $SIG{VTALRM} = sub { print time, "\n" }; |
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360 | setitimer(ITIMER_VIRTUAL, 10, 2.5); |
361 | |
1a7d3a53 |
362 | use Time::HiRes qw( clock_gettime clock_getres CLOCK_REALTIME ); |
363 | # Read the POSIX high resolution timer. |
364 | my $high = clock_getres(CLOCK_REALTIME); |
365 | # But how accurate we can be, really? |
366 | my $reso = clock_getres(CLOCK_REALTIME); |
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367 | |
dcf686c9 |
368 | =head1 C API |
369 | |
370 | In addition to the perl API described above, a C API is available for |
371 | extension writers. The following C functions are available in the |
372 | modglobal hash: |
373 | |
374 | name C prototype |
375 | --------------- ---------------------- |
376 | Time::NVtime double (*)() |
06252d99 |
377 | Time::U2time void (*)(pTHX_ UV ret[2]) |
dcf686c9 |
378 | |
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379 | Both functions return equivalent information (like C<gettimeofday>) |
380 | but with different representations. The names C<NVtime> and C<U2time> |
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381 | were selected mainly because they are operating system independent. |
56c1b3bd |
382 | (C<gettimeofday> is Unix-centric, though some platforms like Win32 and |
383 | VMS have emulations for it.) |
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384 | |
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385 | Here is an example of using C<NVtime> from C: |
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386 | |
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387 | double (*myNVtime)(); /* Returns -1 on failure. */ |
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388 | SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0); |
389 | if (!svp) croak("Time::HiRes is required"); |
390 | if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer"); |
356234a5 |
391 | myNVtime = INT2PTR(double(*)(), SvIV(*svp)); |
dcf686c9 |
392 | printf("The current time is: %f\n", (*myNVtime)()); |
393 | |
db0b859f |
394 | =head1 DIAGNOSTICS |
395 | |
396 | =head2 negative time not invented yet |
397 | |
398 | You tried to use a negative time argument. |
399 | |
400 | =head2 internal error: useconds < 0 (unsigned ... signed ...) |
401 | |
402 | Something went horribly wrong-- the number of microseconds that cannot |
403 | become negative just became negative. Maybe your compiler is broken? |
404 | |
f03b998d |
405 | =head1 CAVEATS |
406 | |
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407 | Notice that the core C<time()> maybe rounding rather than truncating. |
d8cb5b61 |
408 | What this means is that the core C<time()> may be reporting the time |
409 | as one second later than C<gettimeofday()> and C<Time::HiRes::time()>. |
410 | |
411 | Adjusting the system clock (either manually or by services like ntp) |
412 | may cause problems, especially for long running programs that assume |
413 | a monotonously increasing time (note that all platforms do not adjust |
414 | time as gracefully as UNIX ntp does). For example in Win32 (and derived |
415 | platforms like Cygwin and MinGW) the Time::HiRes::time() may temporarily |
416 | drift off from the system clock (and the original time()) by up to 0.5 |
417 | seconds. Time::HiRes will notice this eventually and recalibrate. |
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418 | Note that since Time::HiRes 1.77 the clock_gettime(CLOCK_MONOTONIC) |
1a7d3a53 |
419 | might help in this (in case your system supports CLOCK_MONOTONIC). |
f03b998d |
420 | |
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421 | =head1 SEE ALSO |
422 | |
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423 | Perl modules L<BSD::Resource>, L<Time::TAI64>. |
424 | |
425 | Your system documentation for C<clock_gettime>, C<clock_settime>, |
426 | C<gettimeofday>, C<getitimer>, C<setitimer>, C<ualarm>. |
26e22fd9 |
427 | |
dcf686c9 |
428 | =head1 AUTHORS |
429 | |
430 | D. Wegscheid <wegscd@whirlpool.com> |
431 | R. Schertler <roderick@argon.org> |
432 | J. Hietaniemi <jhi@iki.fi> |
433 | G. Aas <gisle@aas.no> |
434 | |
3f2ee006 |
435 | =head1 COPYRIGHT AND LICENSE |
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436 | |
3f2ee006 |
437 | Copyright (c) 1996-2002 Douglas E. Wegscheid. All rights reserved. |
dcf686c9 |
438 | |
0cf8ddea |
439 | Copyright (c) 2002, 2003, 2004, 2005 Jarkko Hietaniemi. All rights reserved. |
dcf686c9 |
440 | |
3f2ee006 |
441 | This program is free software; you can redistribute it and/or modify |
442 | it under the same terms as Perl itself. |
dcf686c9 |
443 | |
444 | =cut |