package Time::HiRes;
use strict;
-use vars qw($VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD);
+use vars qw($VERSION $XS_VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD);
require Exporter;
-use XSLoader;
+require DynaLoader;
-@ISA = qw(Exporter);
+@ISA = qw(Exporter DynaLoader);
@EXPORT = qw( );
@EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval
- getitimer setitimer ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF);
-
-$VERSION = '1.20_00';
+ getitimer setitimer
+ ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF
+ d_usleep d_ualarm d_gettimeofday d_getitimer d_setitimer
+ d_nanosleep);
+
+$VERSION = '1.54';
+$XS_VERSION = $VERSION;
+$VERSION = eval $VERSION;
sub AUTOLOAD {
my $constname;
- ($constname= $AUTOLOAD) =~ s/.*:://;
- my $val = constant($constname, @_ ? $_[0] : 0);
- if ($!) {
- my ($pack,$file,$line) = caller;
- die "Your vendor has not defined Time::HiRes macro $constname, used at $file line $line.\n";
- }
+ ($constname = $AUTOLOAD) =~ s/.*:://;
+ die "&Time::HiRes::constant not defined" if $constname eq 'constant';
+ my ($error, $val) = constant($constname);
+ if ($error) { die $error; }
{
no strict 'refs';
*$AUTOLOAD = sub { $val };
goto &$AUTOLOAD;
}
-XSLoader::load 'Time::HiRes', $VERSION;
+bootstrap Time::HiRes;
# Preloaded methods go here.
=head1 NAME
-Time::HiRes - High resolution ualarm, usleep, and gettimeofday
+Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers
=head1 SYNOPSIS
alarm ($floating_seconds, $floating_interval);
use Time::HiRes qw( setitimer getitimer
- ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF );
+ ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF );
setitimer ($which, $floating_seconds, $floating_interval );
getitimer ($which);
=head1 DESCRIPTION
-The C<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.
+The C<Time::HiRes> module implements a Perl interface to the C<usleep>,
+C<ualarm>, C<gettimeofday>, and C<setitimer>/C<getitimer> system calls, in other
+words, high resolution time and timers. See the L</EXAMPLES> section below
+and the test scripts for usage; see your system documentation for the
+description of the underlying C<nanosleep> or C<usleep>, C<ualarm>,
+C<gettimeofday>, and C<setitimer>/C<getitimer> calls.
+
+If your system lacks C<gettimeofday()> or an emulation of it you don't
+get C<gettimeofday()> or the one-argument form of C<tv_interval()>. If your system lacks all of
+C<nanosleep()>, C<usleep()>, and C<select()>, you don't get
+C<Time::HiRes::usleep()> or C<Time::HiRes::sleep()>. If your system lacks both
+C<ualarm()> and C<setitimer()> you don't get
+C<Time::HiRes::ualarm()> or C<Time::HiRes::alarm()>.
-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 C<use> statement
it will fail at compile time.
+If your subsecond sleeping is implemented with C<nanosleep()> instead of
+C<usleep()>, you can mix subsecond sleeping with signals since
+C<nanosleep()> does not use signals. This, however is unportable, and you
+should first check for the truth value of C<&Time::HiRes::d_nanosleep> to
+see whether you have nanosleep, and then carefully read your
+C<nanosleep()> C API documentation for any peculiarities. (There is no
+separate interface to call C<nanosleep()>; just use C<Time::HiRes::sleep()>
+or C<Time::HiRes::usleep()> with small enough values.)
+
+Unless using C<nanosleep> for mixing sleeping with signals, give
+some thought to whether Perl is the tool you should be using for work
+requiring nanosecond accuracies.
+
The following functions can be imported from this module.
No functions are exported by default.
=item gettimeofday ()
-In array context it returns a 2 element array with the seconds and
-microseconds since the epoch. In scalar context it returns floating
-seconds like Time::HiRes::time() (see below).
+In array context returns a two-element array with the seconds and
+microseconds since the epoch. In scalar context returns floating
+seconds like C<Time::HiRes::time()> (see below).
=item usleep ( $useconds )
-Issues a usleep for the number of microseconds specified. See also
-Time::HiRes::sleep() below.
+Sleeps for the number of microseconds specified. Returns the number
+of microseconds actually slept. Can sleep for more than one second,
+unlike the C<usleep> system call. See also C<Time::HiRes::sleep()> below.
=item ualarm ( $useconds [, $interval_useconds ] )
-Issues a ualarm call; interval_useconds is optional and will be 0 if
-unspecified, resulting in alarm-like behaviour.
+Issues a C<ualarm> call; the C<$interval_useconds> is optional and
+will be zero if unspecified, resulting in C<alarm>-like behaviour.
=item tv_interval
-S<tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )>
+tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )
-Returns the floating seconds between the two times, which should have been
-returned by gettimeofday(). If the second argument is omitted, then the
-current time is used.
+Returns the floating seconds between the two times, which should have
+been returned by C<gettimeofday()>. If the second argument is omitted,
+then the current time is used.
=item time ()
-Returns a floating seconds since the epoch. This function can be imported,
-resulting in a nice drop-in replacement for the C<time> provided with perl,
-see the EXAMPLES below.
-
-B<NOTE>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT the
-default floating point format of Perl and the seconds since epoch
-have conspired to produce an apparent bug: if you print the value
-of Time::HiRes::time() you seem to be getting only five decimals,
-not six as promised (microseconds). Not to worry, the microseconds
-are there (assuming your platform supports such granularity).
+Returns a floating seconds since the epoch. This function can be
+imported, resulting in a nice drop-in replacement for the C<time>
+provided with core Perl; see the L</EXAMPLES> below.
+
+B<NOTE 1>: This higher resolution timer can return values either less
+or more than the core C<time()>, depending on whether your platform
+rounds the higher resolution timer values up, down, or to the nearest second
+to get the core C<time()>, but naturally the difference should be never
+more than half a second.
+
+B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT, when
+the C<time()> seconds since epoch rolled over to 1_000_000_000, the
+default floating point format of Perl and the seconds since epoch have
+conspired to produce an apparent bug: if you print the value of
+C<Time::HiRes::time()> you seem to be getting only five decimals, not six
+as promised (microseconds). Not to worry, the microseconds are there
+(assuming your platform supports such granularity in first place).
What is going on is that the default floating point format of Perl
only outputs 15 digits. In this case that means ten digits before the
decimal separator and five after. To see the microseconds you can use
-either printf/sprintf with C<%.6f>, or the gettimeofday() function in
+either C<printf>/C<sprintf> with C<"%.6f">, or the C<gettimeofday()> function in
list context, which will give you the seconds and microseconds as two
separate values.
=item sleep ( $floating_seconds )
-Converts $floating_seconds to microseconds and issues a usleep for the
-result. This function can be imported, resulting in a nice drop-in
-replacement for the C<sleep> provided with perl, see the EXAMPLES below.
+Sleeps for the specified amount of seconds. Returns the number of
+seconds actually slept (a floating point value). This function can be
+imported, resulting in a nice drop-in replacement for the C<sleep>
+provided with perl, see the L</EXAMPLES> below.
=item alarm ( $floating_seconds [, $interval_floating_seconds ] )
-Converts $floating_seconds and $interval_floating_seconds and issues
-a ualarm for the results. The $interval_floating_seconds argument
-is optional and will be 0 if unspecified, resulting in alarm-like
+The C<SIGALRM> signal is sent after the specified number of seconds.
+Implemented using C<ualarm()>. The C<$interval_floating_seconds> argument
+is optional and will be zero if unspecified, resulting in C<alarm()>-like
behaviour. This function can be imported, resulting in a nice drop-in
-replacement for the C<alarm> provided with perl, see the EXAMPLES below.
+replacement for the C<alarm> provided with perl, see the L</EXAMPLES> below.
-=item setitimer
+B<NOTE 1>: With some operating system and Perl release combinations
+C<SIGALRM> restarts C<select()>, instead of interuping it.
+This means that an C<alarm()> followed by a C<select()>
+may together take the sum of the times specified for the the
+C<alarm()> and the C<select()>, not just the time of the C<alarm()>.
-S<setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] )>
+=item setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] )
-Start up an interval timer: after a certain time, a signal is arrives,
-and more may keep arriving at certain intervals. To disable a timer,
-use time of zero. If interval is set to zero (or unspecified), the
-timer is disabled after the next delivered signal.
+Start up an interval timer: after a certain time, a signal arrives,
+and more signals may keep arriving at certain intervals. To disable a
+timer, use C<$floating_seconds> of zero. If the C<$interval_floating_seconds>
+is set to zero (or unspecified), the timer is disabled B<after> the
+next delivered signal.
-Use of interval timers may interfere with alarm(), sleep(), and usleep().
-In standard-speak the "interaction is unspecified", which means that
-I<anything> may happen: it may work, it may not.
+Use of interval timers may interfere with C<alarm()>, C<sleep()>,
+and C<usleep()>. In standard-speak the "interaction is unspecified",
+which means that I<anything> may happen: it may work, it may not.
In scalar context, the remaining time in the timer is returned.
In list context, both the remaining time and the interval are returned.
-There are three interval timers: the $which can be ITIMER_REAL,
-ITIMER_VIRTUAL, or ITIMER_PROF.
+There are usually three or four interval timers available: the C<$which>
+can be C<ITIMER_REAL>, C<ITIMER_VIRTUAL>, C<ITIMER_PROF>, or C<ITIMER_REALPROF>.
+Note that which ones are available depends: true UNIX platforms usually
+have the first three, but (for example) Win32 and Cygwin have only
+C<ITIMER_REAL>, and only Solaris seems to have C<ITIMER_REALPROF> (which is
+used to profile multithreaded programs).
-ITIMER_REAL results in alarm()-like behavior. Time is counted in
-I<real time>, that is, wallclock time. SIGALRM is delivered when
+C<ITIMER_REAL> results in C<alarm()>-like behavior. Time is counted in
+I<real time>; that is, wallclock time. C<SIGALRM> is delivered when
the timer expires.
-ITIMER_VIRTUAL counts time in (process) I<virtual time>, that is, only
-when the process is running. In multiprocessing/user/CPU systems this
-may be much less than real time. (This time is also known as the
-I<user time>.) SIGVTALRM is delivered when the timer expires.
+C<ITIMER_VIRTUAL> counts time in (process) I<virtual time>; that is, only
+when the process is running. In multiprocessor/user/CPU systems this
+may be more or less than real or wallclock time. (This time is also
+known as the I<user time>.) C<SIGVTALRM> is delivered when the timer expires.
-ITIMER_PROF counts time when either the process virtual time or when
-the operating system is running on behalf of the process (such as
-I/O). (This time is also known as the I<system time>.) (Collectively
-these times are also known as the I<CPU time>.) SIGPROF is delivered
-when the timer expires. SIGPROF can interrupt system calls.
+C<ITIMER_PROF> counts time when either the process virtual time or when
+the operating system is running on behalf of the process (such as I/O).
+(This time is also known as the I<system time>.) (The sum of user
+time and system time is known as the I<CPU time>.) C<SIGPROF> is
+delivered when the timer expires. C<SIGPROF> can interrupt system calls.
The semantics of interval timers for multithreaded programs are
system-specific, and some systems may support additional interval
-timers. See your setitimer() documentation.
+timers. See your C<setitimer()> documentation.
=item getitimer ( $which )
-Return the remaining time in the interval timer specified by $which.
+Return the remaining time in the interval timer specified by C<$which>.
In scalar context, the remaining time is returned.
In list context, both the remaining time and the interval are returned.
-The interval is always what you put in using setitimer().
+The interval is always what you put in using C<setitimer()>.
=back
$t1 = [gettimeofday];
# do more stuff here
$t0_t1 = tv_interval $t0, $t1;
-
+
$elapsed = tv_interval ($t0, [gettimeofday]);
$elapsed = tv_interval ($t0); # equivalent code
$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);
use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time );
- $SIG{VTLARM} = sub { print time, "\n" };
+ $SIG{VTALRM} = sub { print time, "\n" };
setitimer(ITIMER_VIRTUAL, 10, 2.5);
=head1 C API
Both functions return equivalent information (like C<gettimeofday>)
but with different representations. The names C<NVtime> and C<U2time>
were selected mainly because they are operating system independent.
-(C<gettimeofday> is Un*x-centric.)
+(C<gettimeofday> is Unix-centric, though some platforms like VMS have
+emulations for it.)
-Here is an example of using NVtime from C:
+Here is an example of using C<NVtime> from C:
double (*myNVtime)();
SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0);
if (!svp) croak("Time::HiRes is required");
if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer");
- myNVtime = (double(*)()) SvIV(*svp);
+ myNVtime = INT2PTR(double(*)(), SvIV(*svp));
printf("The current time is: %f\n", (*myNVtime)());
+=head1 DIAGNOSTICS
+
+=head2 negative time not invented yet
+
+You tried to use a negative time argument.
+
+=head2 internal error: useconds < 0 (unsigned ... signed ...)
+
+Something went horribly wrong-- the number of microseconds that cannot
+become negative just became negative. Maybe your compiler is broken?
+
=head1 CAVEATS
-Notice that the core time() maybe rounding rather than truncating.
-What this means that the core time() may be giving time one second
-later than gettimeofday(), also known as Time::HiRes::time().
+Notice that the core C<time()> maybe rounding rather than truncating.
+What this means is that the core C<time()> may be reporting the time as one second
+later than C<gettimeofday()> and C<Time::HiRes::time()>.
=head1 AUTHORS
J. Hietaniemi <jhi@iki.fi>
G. Aas <gisle@aas.no>
-=head1 REVISION
-
-$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
+=head1 COPYRIGHT AND LICENSE
-Revision 1.0 1996/09/03 18:25:15 wegscd
-Initial revision
+Copyright (c) 1996-2002 Douglas E. Wegscheid. All rights reserved.
-=head1 COPYRIGHT
+Copyright (c) 2002,2003,2004 Jarkko Hietaniemi. All rights reserved.
-Copyright (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.
+This program is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff