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1 | package Time::HiRes; |
2 | |
3 | use strict; |
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4 | use vars qw($VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD); |
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5 | |
6 | require Exporter; |
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7 | use XSLoader; |
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8 | |
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9 | @ISA = qw(Exporter); |
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10 | |
11 | @EXPORT = qw( ); |
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12 | @EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval |
13 | getitimer setitimer ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF); |
14 | |
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15 | $VERSION = '1.20_00'; |
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16 | |
17 | sub AUTOLOAD { |
18 | my $constname; |
19 | ($constname= $AUTOLOAD) =~ s/.*:://; |
20 | my $val = constant($constname, @_ ? $_[0] : 0); |
21 | if ($!) { |
22 | my ($pack,$file,$line) = caller; |
23 | die "Your vendor has not defined Time::HiRes macro $constname, used at $file line $line.\n"; |
24 | } |
25 | { |
26 | no strict 'refs'; |
27 | *$AUTOLOAD = sub { $val }; |
28 | } |
29 | goto &$AUTOLOAD; |
30 | } |
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31 | |
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32 | XSLoader::load 'Time::HiRes', $VERSION; |
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33 | |
34 | # Preloaded methods go here. |
35 | |
36 | sub tv_interval { |
37 | # probably could have been done in C |
38 | my ($a, $b) = @_; |
39 | $b = [gettimeofday()] unless defined($b); |
40 | (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000); |
41 | } |
42 | |
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43 | # Autoload methods go after =cut, and are processed by the autosplit program. |
44 | |
45 | 1; |
46 | __END__ |
47 | |
48 | =head1 NAME |
49 | |
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50 | Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers |
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51 | |
52 | =head1 SYNOPSIS |
53 | |
54 | use Time::HiRes qw( usleep ualarm gettimeofday tv_interval ); |
55 | |
56 | usleep ($microseconds); |
57 | |
58 | ualarm ($microseconds); |
59 | ualarm ($microseconds, $interval_microseconds); |
60 | |
61 | $t0 = [gettimeofday]; |
62 | ($seconds, $microseconds) = gettimeofday; |
63 | |
64 | $elapsed = tv_interval ( $t0, [$seconds, $microseconds]); |
65 | $elapsed = tv_interval ( $t0, [gettimeofday]); |
66 | $elapsed = tv_interval ( $t0 ); |
67 | |
68 | use Time::HiRes qw ( time alarm sleep ); |
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69 | |
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70 | $now_fractions = time; |
71 | sleep ($floating_seconds); |
72 | alarm ($floating_seconds); |
73 | alarm ($floating_seconds, $floating_interval); |
74 | |
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75 | use Time::HiRes qw( setitimer getitimer |
76 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ); |
77 | |
78 | setitimer ($which, $floating_seconds, $floating_interval ); |
79 | getitimer ($which); |
80 | |
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81 | =head1 DESCRIPTION |
82 | |
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83 | The C<Time::HiRes> module implements a Perl interface to the usleep, |
84 | ualarm, gettimeofday, and setitimer/getitimer system calls. See the |
85 | EXAMPLES section below and the test scripts for usage; see your system |
86 | documentation for the description of the underlying usleep, ualarm, |
87 | gettimeofday, and setitimer/getitimer calls. |
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88 | |
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89 | If your system lacks gettimeofday(2) or an emulation of it you don't |
90 | get gettimeofday() or the one-arg form of tv_interval(). |
91 | If you don't have usleep(3) or select(2) you don't get usleep() |
92 | or sleep(). If your system don't have ualarm(3) or setitimer(2) you |
93 | don't get ualarm() or alarm(). If you try to import an unimplemented |
94 | function in the C<use> statement it will fail at compile time. |
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95 | |
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96 | The following functions can be imported from this module. |
97 | No functions are exported by default. |
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98 | |
99 | =over 4 |
100 | |
101 | =item gettimeofday () |
102 | |
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103 | In array context returns a 2 element array with the seconds and |
104 | microseconds since the epoch. In scalar context returns floating |
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105 | seconds like Time::HiRes::time() (see below). |
106 | |
107 | =item usleep ( $useconds ) |
108 | |
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109 | Sleeps for the number of microseconds specified. Returns the number |
110 | of microseconds actually slept. Can sleep for more than one second |
111 | unlike the usleep system call. See also Time::HiRes::sleep() below. |
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112 | |
113 | =item ualarm ( $useconds [, $interval_useconds ] ) |
114 | |
115 | Issues a ualarm call; interval_useconds is optional and will be 0 if |
116 | unspecified, resulting in alarm-like behaviour. |
117 | |
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118 | =item tv_interval |
119 | |
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120 | C<tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )> |
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121 | |
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122 | Returns the floating seconds between the two times, which should have |
123 | been returned by gettimeofday(). If the second argument is omitted, |
124 | then the current time is used. |
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125 | |
126 | =item time () |
127 | |
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128 | Returns a floating seconds since the epoch. This function can be |
129 | imported, resulting in a nice drop-in replacement for the C<time> |
130 | provided with core Perl, see the EXAMPLES below. |
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131 | |
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132 | B<NOTE 1>: this higher resolution timer can return values either less or |
133 | more than the core time(), depending on whether your platforms rounds |
134 | the higher resolution timer values up, down, or to the nearest to get |
135 | the core time(), but naturally the difference should be never more than |
136 | half a second. |
137 | |
138 | B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT |
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139 | (when the time() seconds since epoch rolled over to 1_000_000_000), |
140 | the default floating point format of Perl and the seconds since epoch |
141 | have conspired to produce an apparent bug: if you print the value of |
142 | Time::HiRes::time() you seem to be getting only five decimals, not six |
143 | as promised (microseconds). Not to worry, the microseconds are there |
144 | (assuming your platform supports such granularity). What is going on |
145 | is that the default floating point format of Perl only outputs 15 |
146 | digits. In this case that means ten digits before the decimal |
147 | separator and five after. To see the microseconds you can use either |
148 | printf/sprintf with C<%.6f>, or the gettimeofday() function in list |
149 | context, which will give you the seconds and microseconds as two |
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150 | separate values. |
151 | |
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152 | =item sleep ( $floating_seconds ) |
153 | |
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154 | Sleeps for the specified amount of seconds. Returns the number of |
155 | seconds actually slept (a floating point value). This function can be |
156 | imported, resulting in a nice drop-in replacement for the C<sleep> |
157 | provided with perl, see the EXAMPLES below. |
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158 | |
159 | =item alarm ( $floating_seconds [, $interval_floating_seconds ] ) |
160 | |
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161 | The SIGALRM signal is sent after the specfified number of seconds. |
162 | Implemented using ualarm(). The $interval_floating_seconds argument |
163 | is optional and will be 0 if unspecified, resulting in alarm()-like |
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164 | behaviour. This function can be imported, resulting in a nice drop-in |
165 | replacement for the C<alarm> provided with perl, see the EXAMPLES below. |
166 | |
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167 | =item setitimer |
168 | |
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169 | C<setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] )> |
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170 | |
171 | Start up an interval timer: after a certain time, a signal is arrives, |
172 | and more may keep arriving at certain intervals. To disable a timer, |
173 | use time of zero. If interval is set to zero (or unspecified), the |
174 | timer is disabled after the next delivered signal. |
175 | |
176 | Use of interval timers may interfere with alarm(), sleep(), and usleep(). |
177 | In standard-speak the "interaction is unspecified", which means that |
178 | I<anything> may happen: it may work, it may not. |
179 | |
180 | In scalar context, the remaining time in the timer is returned. |
181 | |
182 | In list context, both the remaining time and the interval are returned. |
183 | |
184 | There are three interval timers: the $which can be ITIMER_REAL, |
185 | ITIMER_VIRTUAL, or ITIMER_PROF. |
186 | |
187 | ITIMER_REAL results in alarm()-like behavior. Time is counted in |
188 | I<real time>, that is, wallclock time. SIGALRM is delivered when |
189 | the timer expires. |
190 | |
191 | ITIMER_VIRTUAL counts time in (process) I<virtual time>, that is, only |
192 | when the process is running. In multiprocessing/user/CPU systems this |
193 | may be much less than real time. (This time is also known as the |
194 | I<user time>.) SIGVTALRM is delivered when the timer expires. |
195 | |
196 | ITIMER_PROF counts time when either the process virtual time or when |
197 | the operating system is running on behalf of the process (such as |
198 | I/O). (This time is also known as the I<system time>.) (Collectively |
199 | these times are also known as the I<CPU time>.) SIGPROF is delivered |
200 | when the timer expires. SIGPROF can interrupt system calls. |
201 | |
202 | The semantics of interval timers for multithreaded programs are |
203 | system-specific, and some systems may support additional interval |
204 | timers. See your setitimer() documentation. |
205 | |
206 | =item getitimer ( $which ) |
207 | |
208 | Return the remaining time in the interval timer specified by $which. |
209 | |
210 | In scalar context, the remaining time is returned. |
211 | |
212 | In list context, both the remaining time and the interval are returned. |
213 | The interval is always what you put in using setitimer(). |
214 | |
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215 | =back |
216 | |
217 | =head1 EXAMPLES |
218 | |
219 | use Time::HiRes qw(usleep ualarm gettimeofday tv_interval); |
220 | |
221 | $microseconds = 750_000; |
222 | usleep $microseconds; |
223 | |
224 | # signal alarm in 2.5s & every .1s thereafter |
225 | ualarm 2_500_000, 100_000; |
226 | |
227 | # get seconds and microseconds since the epoch |
228 | ($s, $usec) = gettimeofday; |
229 | |
230 | # measure elapsed time |
231 | # (could also do by subtracting 2 gettimeofday return values) |
232 | $t0 = [gettimeofday]; |
233 | # do bunch of stuff here |
234 | $t1 = [gettimeofday]; |
235 | # do more stuff here |
236 | $t0_t1 = tv_interval $t0, $t1; |
237 | |
238 | $elapsed = tv_interval ($t0, [gettimeofday]); |
239 | $elapsed = tv_interval ($t0); # equivalent code |
240 | |
241 | # |
242 | # replacements for time, alarm and sleep that know about |
243 | # floating seconds |
244 | # |
245 | use Time::HiRes; |
246 | $now_fractions = Time::HiRes::time; |
247 | Time::HiRes::sleep (2.5); |
248 | Time::HiRes::alarm (10.6666666); |
249 | |
250 | use Time::HiRes qw ( time alarm sleep ); |
251 | $now_fractions = time; |
252 | sleep (2.5); |
253 | alarm (10.6666666); |
254 | |
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255 | # Arm an interval timer to go off first at 10 seconds and |
256 | # after that every 2.5 seconds, in process virtual time |
257 | |
258 | use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time ); |
259 | |
260 | $SIG{VTLARM} = sub { print time, "\n" }; |
261 | setitimer(ITIMER_VIRTUAL, 10, 2.5); |
262 | |
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263 | =head1 C API |
264 | |
265 | In addition to the perl API described above, a C API is available for |
266 | extension writers. The following C functions are available in the |
267 | modglobal hash: |
268 | |
269 | name C prototype |
270 | --------------- ---------------------- |
271 | Time::NVtime double (*)() |
272 | Time::U2time void (*)(UV ret[2]) |
273 | |
274 | Both functions return equivalent information (like C<gettimeofday>) |
275 | but with different representations. The names C<NVtime> and C<U2time> |
276 | were selected mainly because they are operating system independent. |
277 | (C<gettimeofday> is Un*x-centric.) |
278 | |
279 | Here is an example of using NVtime from C: |
280 | |
281 | double (*myNVtime)(); |
282 | SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0); |
283 | if (!svp) croak("Time::HiRes is required"); |
284 | if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer"); |
285 | myNVtime = (double(*)()) SvIV(*svp); |
286 | printf("The current time is: %f\n", (*myNVtime)()); |
287 | |
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288 | =head1 CAVEATS |
289 | |
290 | Notice that the core time() maybe rounding rather than truncating. |
291 | What this means that the core time() may be giving time one second |
292 | later than gettimeofday(), also known as Time::HiRes::time(). |
293 | |
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294 | =head1 AUTHORS |
295 | |
296 | D. Wegscheid <wegscd@whirlpool.com> |
297 | R. Schertler <roderick@argon.org> |
298 | J. Hietaniemi <jhi@iki.fi> |
299 | G. Aas <gisle@aas.no> |
300 | |
301 | =head1 REVISION |
302 | |
303 | $Id: HiRes.pm,v 1.20 1999/03/16 02:26:13 wegscd Exp $ |
304 | |
305 | $Log: HiRes.pm,v $ |
306 | Revision 1.20 1999/03/16 02:26:13 wegscd |
307 | Add documentation for NVTime and U2Time. |
308 | |
309 | Revision 1.19 1998/09/30 02:34:42 wegscd |
310 | No changes, bump version. |
311 | |
312 | Revision 1.18 1998/07/07 02:41:35 wegscd |
313 | No changes, bump version. |
314 | |
315 | Revision 1.17 1998/07/02 01:45:13 wegscd |
316 | Bump version to 1.17 |
317 | |
318 | Revision 1.16 1997/11/13 02:06:36 wegscd |
319 | version bump to accomodate HiRes.xs fix. |
320 | |
321 | Revision 1.15 1997/11/11 02:17:59 wegscd |
322 | POD editing, courtesy of Gisle Aas. |
323 | |
324 | Revision 1.14 1997/11/06 03:14:35 wegscd |
325 | Update version # for Makefile.PL and HiRes.xs changes. |
326 | |
327 | Revision 1.13 1997/11/05 05:36:25 wegscd |
328 | change version # for Makefile.pl and HiRes.xs changes. |
329 | |
330 | Revision 1.12 1997/10/13 20:55:33 wegscd |
331 | Force a new version for Makefile.PL changes. |
332 | |
333 | Revision 1.11 1997/09/05 19:59:33 wegscd |
334 | New version to bump version for README and Makefile.PL fixes. |
335 | Fix bad RCS log. |
336 | |
337 | Revision 1.10 1997/05/23 01:11:38 wegscd |
338 | Conditional compilation; EXPORT_FAIL fixes. |
339 | |
340 | Revision 1.2 1996/12/30 13:28:40 wegscd |
341 | Update documentation for what to do when missing ualarm() and friends. |
342 | |
343 | Revision 1.1 1996/10/17 20:53:31 wegscd |
344 | Fix =head1 being next to __END__ so pod2man works |
345 | |
346 | Revision 1.0 1996/09/03 18:25:15 wegscd |
347 | Initial revision |
348 | |
349 | =head1 COPYRIGHT |
350 | |
351 | Copyright (c) 1996-1997 Douglas E. Wegscheid. |
352 | All rights reserved. This program is free software; you can |
353 | redistribute it and/or modify it under the same terms as Perl itself. |
354 | |
355 | =cut |