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1 | package Time::HiRes; |
2 | |
3 | use strict; |
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4 | use vars qw($VERSION $XS_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 | $XS_VERSION = $VERSION; |
17 | $VERSION = eval $VERSION; |
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18 | |
19 | sub AUTOLOAD { |
20 | my $constname; |
21 | ($constname= $AUTOLOAD) =~ s/.*:://; |
22 | my $val = constant($constname, @_ ? $_[0] : 0); |
23 | if ($!) { |
24 | my ($pack,$file,$line) = caller; |
25 | die "Your vendor has not defined Time::HiRes macro $constname, used at $file line $line.\n"; |
26 | } |
27 | { |
28 | no strict 'refs'; |
29 | *$AUTOLOAD = sub { $val }; |
30 | } |
31 | goto &$AUTOLOAD; |
32 | } |
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33 | |
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34 | XSLoader::load 'Time::HiRes', $XS_VERSION; |
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35 | |
36 | # Preloaded methods go here. |
37 | |
38 | sub tv_interval { |
39 | # probably could have been done in C |
40 | my ($a, $b) = @_; |
41 | $b = [gettimeofday()] unless defined($b); |
42 | (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000); |
43 | } |
44 | |
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45 | # Autoload methods go after =cut, and are processed by the autosplit program. |
46 | |
47 | 1; |
48 | __END__ |
49 | |
50 | =head1 NAME |
51 | |
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52 | Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers |
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53 | |
54 | =head1 SYNOPSIS |
55 | |
56 | use Time::HiRes qw( usleep ualarm gettimeofday tv_interval ); |
57 | |
58 | usleep ($microseconds); |
59 | |
60 | ualarm ($microseconds); |
61 | ualarm ($microseconds, $interval_microseconds); |
62 | |
63 | $t0 = [gettimeofday]; |
64 | ($seconds, $microseconds) = gettimeofday; |
65 | |
66 | $elapsed = tv_interval ( $t0, [$seconds, $microseconds]); |
67 | $elapsed = tv_interval ( $t0, [gettimeofday]); |
68 | $elapsed = tv_interval ( $t0 ); |
69 | |
70 | use Time::HiRes qw ( time alarm sleep ); |
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71 | |
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72 | $now_fractions = time; |
73 | sleep ($floating_seconds); |
74 | alarm ($floating_seconds); |
75 | alarm ($floating_seconds, $floating_interval); |
76 | |
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77 | use Time::HiRes qw( setitimer getitimer |
78 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ); |
79 | |
80 | setitimer ($which, $floating_seconds, $floating_interval ); |
81 | getitimer ($which); |
82 | |
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83 | =head1 DESCRIPTION |
84 | |
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85 | The C<Time::HiRes> module implements a Perl interface to the usleep, |
86 | ualarm, gettimeofday, and setitimer/getitimer system calls. See the |
87 | EXAMPLES section below and the test scripts for usage; see your system |
88 | documentation for the description of the underlying usleep, ualarm, |
89 | gettimeofday, and setitimer/getitimer calls. |
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90 | |
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91 | If your system lacks gettimeofday(2) or an emulation of it you don't |
92 | get gettimeofday() or the one-arg form of tv_interval(). |
93 | If you don't have usleep(3) or select(2) you don't get usleep() |
94 | or sleep(). If your system don't have ualarm(3) or setitimer(2) you |
95 | don't get ualarm() or alarm(). If you try to import an unimplemented |
96 | function in the C<use> statement it will fail at compile time. |
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97 | |
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98 | The following functions can be imported from this module. |
99 | No functions are exported by default. |
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100 | |
101 | =over 4 |
102 | |
103 | =item gettimeofday () |
104 | |
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105 | In array context returns a 2 element array with the seconds and |
106 | microseconds since the epoch. In scalar context returns floating |
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107 | seconds like Time::HiRes::time() (see below). |
108 | |
109 | =item usleep ( $useconds ) |
110 | |
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111 | Sleeps for the number of microseconds specified. Returns the number |
112 | of microseconds actually slept. Can sleep for more than one second |
113 | unlike the usleep system call. See also Time::HiRes::sleep() below. |
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114 | |
115 | =item ualarm ( $useconds [, $interval_useconds ] ) |
116 | |
117 | Issues a ualarm call; interval_useconds is optional and will be 0 if |
118 | unspecified, resulting in alarm-like behaviour. |
119 | |
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120 | =item tv_interval |
121 | |
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122 | C<tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )> |
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123 | |
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124 | Returns the floating seconds between the two times, which should have |
125 | been returned by gettimeofday(). If the second argument is omitted, |
126 | then the current time is used. |
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127 | |
128 | =item time () |
129 | |
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130 | Returns a floating seconds since the epoch. This function can be |
131 | imported, resulting in a nice drop-in replacement for the C<time> |
132 | provided with core Perl, see the EXAMPLES below. |
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133 | |
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134 | B<NOTE 1>: this higher resolution timer can return values either less or |
135 | more than the core time(), depending on whether your platforms rounds |
136 | the higher resolution timer values up, down, or to the nearest to get |
137 | the core time(), but naturally the difference should be never more than |
138 | half a second. |
139 | |
140 | B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT |
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141 | (when the time() seconds since epoch rolled over to 1_000_000_000), |
142 | the default floating point format of Perl and the seconds since epoch |
143 | have conspired to produce an apparent bug: if you print the value of |
144 | Time::HiRes::time() you seem to be getting only five decimals, not six |
145 | as promised (microseconds). Not to worry, the microseconds are there |
146 | (assuming your platform supports such granularity). What is going on |
147 | is that the default floating point format of Perl only outputs 15 |
148 | digits. In this case that means ten digits before the decimal |
149 | separator and five after. To see the microseconds you can use either |
150 | printf/sprintf with C<%.6f>, or the gettimeofday() function in list |
151 | context, which will give you the seconds and microseconds as two |
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152 | separate values. |
153 | |
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154 | =item sleep ( $floating_seconds ) |
155 | |
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156 | Sleeps for the specified amount of seconds. Returns the number of |
157 | seconds actually slept (a floating point value). This function can be |
158 | imported, resulting in a nice drop-in replacement for the C<sleep> |
159 | provided with perl, see the EXAMPLES below. |
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160 | |
161 | =item alarm ( $floating_seconds [, $interval_floating_seconds ] ) |
162 | |
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163 | The SIGALRM signal is sent after the specfified number of seconds. |
164 | Implemented using ualarm(). The $interval_floating_seconds argument |
165 | is optional and will be 0 if unspecified, resulting in alarm()-like |
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166 | behaviour. This function can be imported, resulting in a nice drop-in |
167 | replacement for the C<alarm> provided with perl, see the EXAMPLES below. |
168 | |
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169 | =item setitimer |
170 | |
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171 | C<setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] )> |
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172 | |
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173 | Start up an interval timer: after a certain time, a signal arrives, |
174 | and more signals may keep arriving at certain intervals. To disable |
175 | a timer, use time of zero. If interval is set to zero (or unspecified), |
176 | the timer is disabled B<after> the next delivered signal. |
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177 | |
178 | Use of interval timers may interfere with alarm(), sleep(), and usleep(). |
179 | In standard-speak the "interaction is unspecified", which means that |
180 | I<anything> may happen: it may work, it may not. |
181 | |
182 | In scalar context, the remaining time in the timer is returned. |
183 | |
184 | In list context, both the remaining time and the interval are returned. |
185 | |
186 | There are three interval timers: the $which can be ITIMER_REAL, |
187 | ITIMER_VIRTUAL, or ITIMER_PROF. |
188 | |
189 | ITIMER_REAL results in alarm()-like behavior. Time is counted in |
190 | I<real time>, that is, wallclock time. SIGALRM is delivered when |
191 | the timer expires. |
192 | |
193 | ITIMER_VIRTUAL counts time in (process) I<virtual time>, that is, only |
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194 | when the process is running. In multiprocessor/user/CPU systems this |
195 | may be more or less than real or wallclock time. (This time is also |
196 | known as the I<user time>.) SIGVTALRM is delivered when the timer expires. |
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197 | |
198 | ITIMER_PROF counts time when either the process virtual time or when |
199 | the operating system is running on behalf of the process (such as |
200 | I/O). (This time is also known as the I<system time>.) (Collectively |
201 | these times are also known as the I<CPU time>.) SIGPROF is delivered |
202 | when the timer expires. SIGPROF can interrupt system calls. |
203 | |
204 | The semantics of interval timers for multithreaded programs are |
205 | system-specific, and some systems may support additional interval |
206 | timers. See your setitimer() documentation. |
207 | |
208 | =item getitimer ( $which ) |
209 | |
210 | Return the remaining time in the interval timer specified by $which. |
211 | |
212 | In scalar context, the remaining time is returned. |
213 | |
214 | In list context, both the remaining time and the interval are returned. |
215 | The interval is always what you put in using setitimer(). |
216 | |
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217 | =back |
218 | |
219 | =head1 EXAMPLES |
220 | |
221 | use Time::HiRes qw(usleep ualarm gettimeofday tv_interval); |
222 | |
223 | $microseconds = 750_000; |
224 | usleep $microseconds; |
225 | |
226 | # signal alarm in 2.5s & every .1s thereafter |
227 | ualarm 2_500_000, 100_000; |
228 | |
229 | # get seconds and microseconds since the epoch |
230 | ($s, $usec) = gettimeofday; |
231 | |
232 | # measure elapsed time |
233 | # (could also do by subtracting 2 gettimeofday return values) |
234 | $t0 = [gettimeofday]; |
235 | # do bunch of stuff here |
236 | $t1 = [gettimeofday]; |
237 | # do more stuff here |
238 | $t0_t1 = tv_interval $t0, $t1; |
239 | |
240 | $elapsed = tv_interval ($t0, [gettimeofday]); |
241 | $elapsed = tv_interval ($t0); # equivalent code |
242 | |
243 | # |
244 | # replacements for time, alarm and sleep that know about |
245 | # floating seconds |
246 | # |
247 | use Time::HiRes; |
248 | $now_fractions = Time::HiRes::time; |
249 | Time::HiRes::sleep (2.5); |
250 | Time::HiRes::alarm (10.6666666); |
251 | |
252 | use Time::HiRes qw ( time alarm sleep ); |
253 | $now_fractions = time; |
254 | sleep (2.5); |
255 | alarm (10.6666666); |
256 | |
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257 | # Arm an interval timer to go off first at 10 seconds and |
258 | # after that every 2.5 seconds, in process virtual time |
259 | |
260 | use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time ); |
261 | |
262 | $SIG{VTLARM} = sub { print time, "\n" }; |
263 | setitimer(ITIMER_VIRTUAL, 10, 2.5); |
264 | |
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265 | =head1 C API |
266 | |
267 | In addition to the perl API described above, a C API is available for |
268 | extension writers. The following C functions are available in the |
269 | modglobal hash: |
270 | |
271 | name C prototype |
272 | --------------- ---------------------- |
273 | Time::NVtime double (*)() |
274 | Time::U2time void (*)(UV ret[2]) |
275 | |
276 | Both functions return equivalent information (like C<gettimeofday>) |
277 | but with different representations. The names C<NVtime> and C<U2time> |
278 | were selected mainly because they are operating system independent. |
279 | (C<gettimeofday> is Un*x-centric.) |
280 | |
281 | Here is an example of using NVtime from C: |
282 | |
283 | double (*myNVtime)(); |
284 | SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0); |
285 | if (!svp) croak("Time::HiRes is required"); |
286 | if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer"); |
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287 | myNVtime = INT2PTR(double(*)(), SvIV(*svp)); |
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288 | printf("The current time is: %f\n", (*myNVtime)()); |
289 | |
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290 | =head1 CAVEATS |
291 | |
292 | Notice that the core time() maybe rounding rather than truncating. |
293 | What this means that the core time() may be giving time one second |
294 | later than gettimeofday(), also known as Time::HiRes::time(). |
295 | |
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296 | =head1 AUTHORS |
297 | |
298 | D. Wegscheid <wegscd@whirlpool.com> |
299 | R. Schertler <roderick@argon.org> |
300 | J. Hietaniemi <jhi@iki.fi> |
301 | G. Aas <gisle@aas.no> |
302 | |
303 | =head1 REVISION |
304 | |
305 | $Id: HiRes.pm,v 1.20 1999/03/16 02:26:13 wegscd Exp $ |
306 | |
307 | $Log: HiRes.pm,v $ |
308 | Revision 1.20 1999/03/16 02:26:13 wegscd |
309 | Add documentation for NVTime and U2Time. |
310 | |
311 | Revision 1.19 1998/09/30 02:34:42 wegscd |
312 | No changes, bump version. |
313 | |
314 | Revision 1.18 1998/07/07 02:41:35 wegscd |
315 | No changes, bump version. |
316 | |
317 | Revision 1.17 1998/07/02 01:45:13 wegscd |
318 | Bump version to 1.17 |
319 | |
320 | Revision 1.16 1997/11/13 02:06:36 wegscd |
321 | version bump to accomodate HiRes.xs fix. |
322 | |
323 | Revision 1.15 1997/11/11 02:17:59 wegscd |
324 | POD editing, courtesy of Gisle Aas. |
325 | |
326 | Revision 1.14 1997/11/06 03:14:35 wegscd |
327 | Update version # for Makefile.PL and HiRes.xs changes. |
328 | |
329 | Revision 1.13 1997/11/05 05:36:25 wegscd |
330 | change version # for Makefile.pl and HiRes.xs changes. |
331 | |
332 | Revision 1.12 1997/10/13 20:55:33 wegscd |
333 | Force a new version for Makefile.PL changes. |
334 | |
335 | Revision 1.11 1997/09/05 19:59:33 wegscd |
336 | New version to bump version for README and Makefile.PL fixes. |
337 | Fix bad RCS log. |
338 | |
339 | Revision 1.10 1997/05/23 01:11:38 wegscd |
340 | Conditional compilation; EXPORT_FAIL fixes. |
341 | |
342 | Revision 1.2 1996/12/30 13:28:40 wegscd |
343 | Update documentation for what to do when missing ualarm() and friends. |
344 | |
345 | Revision 1.1 1996/10/17 20:53:31 wegscd |
346 | Fix =head1 being next to __END__ so pod2man works |
347 | |
348 | Revision 1.0 1996/09/03 18:25:15 wegscd |
349 | Initial revision |
350 | |
351 | =head1 COPYRIGHT |
352 | |
353 | Copyright (c) 1996-1997 Douglas E. Wegscheid. |
354 | All rights reserved. This program is free software; you can |
355 | redistribute it and/or modify it under the same terms as Perl itself. |
356 | |
357 | =cut |