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Manpages HiResSection: User Contributed Perl Documentation (3)Updated: perl v5.6.0 Index Return to Main Contents NAMETime::HiRes - High resolution ualarm, usleep, and gettimeofdaySYNOPSISuse Time::HiRes qw( usleep ualarm gettimeofday tv_interval ); usleep ($microseconds); ualarm ($microseconds); ualarm ($microseconds, $interval_microseconds); $t0 = [gettimeofday]; ($seconds, $microseconds) = gettimeofday; $elapsed = tv_interval ( $t0, [$seconds, $microseconds]); $elapsed = tv_interval ( $t0, [gettimeofday]); $elapsed = tv_interval ( $t0 ); use Time::HiRes qw ( time alarm sleep ); $now_fractions = time; sleep ($floating_seconds); alarm ($floating_seconds); alarm ($floating_seconds, $floating_interval); DESCRIPTIONThe `Time::HiRes' module implements a Perl interface to the usleep, ualarm, and gettimeofday system calls. See the EXAMPLES section below and the test scripts for usage; see your system documentation for the description of the underlying gettimeofday, usleep, and ualarm calls.If your system lacks gettimeofday(2) you don't get gettimeofday() or the one-arg form of tv_interval(). If you don't have usleep(3) or select(2) you don't get usleep() or sleep(). If your system don't have ualarm(3) or setitimer(2) you don't get ualarm() or alarm(). If you try to import an unimplemented function in the `use' statement it will fail at compile time.
The following functions can be imported from this module. No
functions are exported by default.
EXAMPLESuse Time::HiRes qw(usleep ualarm gettimeofday tv_interval); $microseconds = 750_000; usleep $microseconds; # signal alarm in 2.5s & every .1s thereafter ualarm 2_500_000, 100_000; # get seconds and microseconds since the epoch ($s, $usec) = gettimeofday; # measure elapsed time # (could also do by subtracting 2 gettimeofday return values) $t0 = [gettimeofday]; # do bunch of stuff here $t1 = [gettimeofday]; # do more stuff here $t0_t1 = tv_interval $t0, $t1; $elapsed = tv_interval ($t0, [gettimeofday]); $elapsed = tv_interval ($t0); # equivalent code # # replacements for time, alarm and sleep that know about # floating seconds # use Time::HiRes; $now_fractions = Time::HiRes::time; Time::HiRes::sleep (2.5); Time::HiRes::alarm (10.6666666); use Time::HiRes qw ( time alarm sleep ); $now_fractions = time; sleep (2.5); alarm (10.6666666); C APIIn addition to the perl API described above, a C API is available for extension writers. The following C functions are available in the modglobal hash:
name C prototype --------------- ---------------------- Time::NVtime double (*)() Time::U2time void (*)(UV ret[2])Both functions return equivalent information (like `gettimeofday') but with different representations. The names `NVtime' and `U2time' were selected mainly because they are operating system independent. (`gettimeofday' is Un*x-centric.) Here is an example of using NVtime from C:
double (*myNVtime)(); SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0); if (!svp) croak("Time::HiRes is required"); if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer"); myNVtime = (double(*)()) SvIV(*svp); printf("The current time is: %f\n", (*myNVtime)()); AUTHORSD. Wegscheid <wegscd@whirlpool.com> R. Schertler <roderick@argon.org> J. Hietaniemi <jhi@iki.fi> G. Aas <gisle@aas.no>REVISION$Id: HiRes.pm,v 1.20 1999/03/16 02:26:13 wegscd Exp $$Log: HiRes.pm,v $ Revision 1.20 1999/03/16 02:26:13 wegscd Add documentation for NVTime and U2Time. Revision 1.19 1998/09/30 02:34:42 wegscd No changes, bump version. Revision 1.18 1998/07/07 02:41:35 wegscd No changes, bump version. Revision 1.17 1998/07/02 01:45:13 wegscd Bump version to 1.17 Revision 1.16 1997/11/13 02:06:36 wegscd version bump to accomodate HiRes.xs fix. Revision 1.15 1997/11/11 02:17:59 wegscd POD editing, courtesy of Gisle Aas. Revision 1.14 1997/11/06 03:14:35 wegscd Update version # for Makefile.PL and HiRes.xs changes. Revision 1.13 1997/11/05 05:36:25 wegscd change version # for Makefile.pl and HiRes.xs changes. Revision 1.12 1997/10/13 20:55:33 wegscd Force a new version for Makefile.PL changes. Revision 1.11 1997/09/05 19:59:33 wegscd New version to bump version for README and Makefile.PL fixes. Fix bad RCS log. Revision 1.10 1997/05/23 01:11:38 wegscd Conditional compilation; EXPORT_FAIL fixes. Revision 1.2 1996/12/30 13:28:40 wegscd Update documentation for what to do when missing ualarm() and friends. Revision 1.1 1996/10/17 20:53:31 wegscd Fix =head1 being next to __END__ so pod2man works Revision 1.0 1996/09/03 18:25:15 wegscd Initial revision COPYRIGHTCopyright (c) 1996-1997 Douglas E. Wegscheid. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
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