NAME

Time::HiRes - Perl extension for ualarm, usleep, and gettimeofday

SYNOPSIS

 use Time::HiRes;

 Time::HiRes::usleep ($microseconds);

 Time::HiRes::ualarm ($microseconds, $interval_microseconds);

 $t0 = [Time::HiRes::gettimeofday];
 ($seconds, $microseconds) = Time::HiRes::gettimeofday;

 $elapsed = Time::HiRes::tv_interval ( $t0, [$seconds, $microseconds]);
 $elapsed = Time::HiRes::tv_interval ( $t0, [Time::HiRes::gettimeofday]);
 $elapsed = Time::HiRes::tv_interval ( $t0 );

 $now_fractions = Time::HiRes::time;

 Time::HiRes::sleep ($floating_seconds);

 Time::HiRes::alarm ($floating_seconds);
 Time::HiRes::alarm ($floating_seconds, $floating_interval);

 use Time::HiRes qw ( time alarm sleep );
 $now_fractions = time;
 sleep ($floating_seconds);
 alarm ($floating_seconds);

DESCRIPTION

The Time::HiRes package implements a Perl interface to 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.

gettimeofday

Returns a 2 element array with the second and microseconds since the epoch.

usleep ( $useconds )

Issues a usleep for the # of microseconds specified. See also Time::HiRes::sleep.

ualarm ( $useconds [, $interval_useconds ] )

Issues a ualarm call; interval_useconds is optional and will be 0 if unspecified, resulting in alarm-like behaviour.

tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )

Returns the floating seconds between the two times, which should have been returned by Time::HiRes::gettimeofday. If the second is omitted, then the current time is use.

time

Returns a floating seconds since the epoch. This function can be exported, resulting in a nice drop-in replacement for the time provided with perl, see the EXAMPLES below.

sleep ( $floating_seconds )

Converts $floating_seconds to microseconds and issues a usleep for the result. This function can be exported, resulting in a nice drop-in replacement for the sleep provided with perl, see the EXAMPLES below.

alarm ( $floating_seconds [, $interval_floating_seconds ] )

Converts $floating_seconds and $interval_floating_seconds and issues a ualarm for the results. $interval_floating_seconds is optional and will be 0 if unspecified, resulting in alarm-like behaviour. This function can be exported, resulting in a nice drop-in replacement for the alarm provided with perl, see the EXAMPLES below.

EXAMPLES

 use Time::HiRes;

 $microseconds = 750_000;
 Time::HiRes::usleep ($microseconds);

 # signal alarm in 2.5s & every .1 s thereafter
 Time::HiRes::ualarm (2_500_000, 100_000);	

 # get seconds and microseconds since the epoch
 ($s, $usec) = Time::HiRes::gettimeofday;

 # measure elapsed time 
 # (could also do by subtracting 2 Time::HiRes:gettimeofday_f return values)
 $t0 = [Time::HiRes::gettimeofday];
 # do bunch of stuff here
 $t1 = [Time::HiRes::gettimeofday];
 # do more stuff here
 $t0_t1 = Time::HiRes::tv_interval ($t0, $t1);
 
 $elapsed = Time::HiRes::tv_interval ($t0, [Time::HiRes::gettimeofday]);
 $elapsed = Time::HiRes::tv_interval ($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);

AUTHOR

D. Wegscheid <wegscd@whirlpool.com>

REVISION

$Id: HiRes.pm,v 1.1 1996/10/17 20:53:31 wegscd Exp $

$Log: HiRes.pm,v $ 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

COPYRIGHT

Copyright (c) 1996 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.