hires.pm

Astercon2 开源软交换 2.2.0

package Time::HiRes;

use strict;
use vars qw($VERSION $XS_VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD);

require Exporter;
require DynaLoader;

@ISA = qw(Exporter DynaLoader);

@EXPORT = qw( );
@EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval
		 getitimer setitimer nanosleep clock_gettime clock_getres
		 clock clock_nanosleep
		 CLOCK_HIGHRES CLOCK_MONOTONIC CLOCK_PROCESS_CPUTIME_ID
		 CLOCK_REALTIME CLOCK_SOFTTIME CLOCK_THREAD_CPUTIME_ID
		 CLOCK_TIMEOFDAY CLOCKS_PER_SEC
		 ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF
		 TIMER_ABSTIME
		 d_usleep d_ualarm d_gettimeofday d_getitimer d_setitimer
		 d_nanosleep d_clock_gettime d_clock_getres
		 d_clock d_clock_nanosleep);
	
$VERSION = '1.86';
$XS_VERSION = $VERSION;
$VERSION = eval $VERSION;

sub AUTOLOAD {
    my $constname;
    ($constname = $AUTOLOAD) =~ s/.*:://;
    # print "AUTOLOAD: constname = $constname ($AUTOLOAD)\n";
    die "&Time::HiRes::constant not defined" if $constname eq 'constant';
    my ($error, $val) = constant($constname);
    # print "AUTOLOAD: error = $error, val = $val\n";
    if ($error) {
        my (undef,$file,$line) = caller;
        die "$error at $file line $line.\n";
    }
    {
	no strict 'refs';
	*$AUTOLOAD = sub { $val };
    }
    goto &$AUTOLOAD;
}

sub import {
    my $this = shift;
    for my $i (@_) {
	if (($i eq 'clock_getres'    && !&d_clock_getres)    ||
	    ($i eq 'clock_gettime'   && !&d_clock_gettime)   ||
	    ($i eq 'clock_nanosleep' && !&d_clock_nanosleep) ||
	    ($i eq 'clock'           && !&d_clock)           ||
	    ($i eq 'nanosleep'       && !&d_nanosleep)       ||
	    ($i eq 'usleep'          && !&d_usleep)          ||
	    ($i eq 'ualarm'          && !&d_ualarm)) {
	    require Carp;
	    Carp::croak("Time::HiRes::$i(): unimplemented in this platform");
	}
    }
    Time::HiRes->export_to_level(1, $this, @_);
}

bootstrap Time::HiRes;

# Preloaded methods go here.

sub tv_interval {
    # probably could have been done in C
    my ($a, $b) = @_;
    $b = [gettimeofday()] unless defined($b);
    (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000);
}

# Autoload methods go after =cut, and are processed by the autosplit program.

1;
__END__

=head1 NAME

Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers

=head1 SYNOPSIS

  use Time::HiRes qw( usleep ualarm gettimeofday tv_interval nanosleep
		      clock_gettime clock_getres clock_nanosleep clock );

  usleep ($microseconds);
  nanosleep ($nanoseconds);

  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);

  use Time::HiRes qw( setitimer getitimer
		      ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF );

  setitimer ($which, $floating_seconds, $floating_interval );
  getitimer ($which);

  $realtime   = clock_gettime(CLOCK_REALTIME);
  $resolution = clock_getres(CLOCK_REALTIME);

  clock_nanosleep(CLOCK_REALTIME, 1.5);
  clock_nanosleep(CLOCK_REALTIME, time() + 10, TIMER_ABSTIME);

  my $ticktock = clock();

=head1 DESCRIPTION

The C<Time::HiRes> module implements a Perl interface to the
C<usleep>, C<nanosleep>, 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()>,
C<select()>, and C<poll>, you don't get C<Time::HiRes::usleep()>,
C<Time::HiRes::nanosleep()>, 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 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 not portable,
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.

If you are using C<nanosleep> for something else than 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.

=over 4

=item gettimeofday ()

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 )

Sleeps for the number of microseconds (millionths of a second)
specified.  Returns the number of microseconds actually slept.  Can
sleep for more than one second, unlike the C<usleep> system call. Can
also sleep for zero seconds, which often works like a I<thread yield>.
See also C<Time::HiRes::usleep()>, C<Time::HiRes::sleep()>, and
C<Time::HiRes::clock_nanosleep()>.

Do not expect usleep() to be exact down to one microsecond.

=item nanosleep ( $nanoseconds )

Sleeps for the number of nanoseconds (1e9ths of a second) specified.
Returns the number of nanoseconds actually slept (accurate only to
microseconds, the nearest thousand of them).  Can sleep for more than
one second.  Can also sleep for zero seconds, which often works like a
I<thread yield>.  See also C<Time::HiRes::sleep()>,
C<Time::HiRes::usleep()>, and C<Time::HiRes::clock_nanosleep()>.

Do not expect nanosleep() to be exact down to one nanosecond.
Getting even accuracy of one thousand nanoseconds is good.

=item ualarm ( $useconds [, $interval_useconds ] )

Issues a C<ualarm> call; the C<$interval_useconds> is optional and
will be zero if unspecified, resulting in C<alarm>-like behaviour.

Note that the interaction between alarms and sleeps is unspecified.

=item tv_interval 

tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] )

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 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.  See also L</clock_getres>, if available
in your system.

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 the 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 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 )

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.

Note that the interaction between alarms and sleeps is unspecified.

=item alarm ( $floating_seconds [, $interval_floating_seconds ] )

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 L</EXAMPLES> below.

B<NOTE 1>: With some combinations of operating systems and Perl
releases C<SIGALRM> restarts C<select()>, instead of interrupting 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