POE::Resource::Clock - phpMan

NAME
    POE::Resource::Clock - internal clock used for ordering the queue

SYNOPSIS
        sub POE::Kernel::USE_POSIXRT { 0 }
        use POE;

DESCRIPTION
    POE::Resource::Clock is a helper module for POE::Kernel. It provides the
    features to keep an internal monotonic clock and a wall clock. It also
    converts between this monotonic clock and the wall clock.

    The monotonic clock is used to keep an ordered queue of events. The wall
    clock is used to communicate the time with user code ("alarm_set" in
    POE::Kernel, "alarm_remove" in POE::Kernel).

    There are 3 possible clock sources in order of preference:
    POSIX::RT::Clock, Time::HiRes and "time" in perlfunc. Only
    "POSIX::RT::Clock" has a separate monotonic and wall clock; the other
    two use the same source for both clocks.

    Clock selection and behaviour is controlled with the following:

  USE_POSIXRT
        export POE_USE_POSIXRT=0
            or
        sub POE::Kernel::USE_POSIXRT { 0 }

    Uses the "monotonic" clock source for queue priority and the "realtime"
    clock source for wall clock. Not used if POSIX::RT::Clock is not
    installed or your system does not have a "monotonic" clock.

    Defaults to true. If you want the old POE behaviour, set this to 0.

  USE_STATIC_EPOCH
        export POE_USE_STATIC_EPOCH=0
            or
        sub POE::Kernel::USE_STATIC_EPOCH { 0 }

    The epoch of the POSIX::RT::Clock monotonic is different from that of
    the realtime clock. For instance on Linux 2.6.18, the monotonic clock is
    the number of seconds since system boot. This epoch is used to convert
    from walltime into monotonic time for "alarm" in POE::Kernel,
    "alarm_add" in POE::Kernel and "alarm_set" in POE::Kernel. If
    "USE_STATIC_EPOCH" is true (the default), then the epoch is calculated
    at load time. If false, the epoch is calculated each time it is needed.

    Defaults to true. Only relevant for if using POSIX::RT::Clock.
    Long-running POE servers should have this set to false so that system
    clock skew does mess up the queue.

    It is important to point out that without a static epoch, the ordering
    of the following two alarms is undefined.

        $poe_kernel->alarm_set( a1 => $time );
        $poe_kernel->alarm_set( a2 => $time );

  USE_EXACT_EPOCH
        export POE_USE_EXACT_EPOCH=1
            or
        sub POE::Kernel::USE_EXACT_EPOCH { 1 }

    There currently no way to exactly get the monotonic clock's epoch.
    Instead the difference between the current monotonic clock value to the
    realtime clock's value is used. This is obviously inexact because there
    is a slight delay between the 2 system calls. Setting USE_EXACT_EPOCH to
    true will calculate an average of this difference over 250 ms or at
    least 20 samples. What's more, the system calls are done in both orders
    (monotonic then realtime, realtime then monotonic) to try and get a more
    exact value.

    Defaults to false. Only relevant if "USE_STATIC_EPOCH" is true.

  USE_HIRES
        export POE_USE_HIRES=0
            or
        sub POE::Kernel::USE_HIRES { 0 }

    Use Time::HiRes as both monotonic and wall clock source. This was POE's
    previous default clock.

    Defaults to true. Only relevant if "USE_POSIXRT" is false. Set this to
    false to use "time" in perlfunc.

EXPORTS
    This module optionally exports a few timekeeping helper functions.

  mono2wall
    mono2wall() converts a monotonic time to an epoch wall time.

      my $wall = mono2wall( $monotonic );

  monotime
    monotime() makes a best-effort attempt to return the time from a
    monotonic system clock. It may fall back to non-monotonic time if there
    are no monotonic clocks available.

      my $monotonic = monotime();

  sleep
    sleep() makes a best-effort attempt to sleep a particular amount of
    high-resolution time using a monotonic clock. This feature will degrade
    gracefully to non-monotonic high-resolution clocks, then low-resolution
    clocks, depending on available libraries.

      sleep( 3.141 );

  time
    time() is a backwards compatible alias for walltime(). Please see
    walltime()'s documentation for details.

  wall2mono
    wall2mono() makes a best-effort attempt to convert wall time to its
    equivalent monotonic-clock time. Its feature degrades gracefully
    depending on clock availability.

      my $monotonic = wall2mono( $epoch );

  walltime
    time() makes a best-effort attempt to return non-monotonic wall time at
    the highest available resolution known.

      my $epoch = walltime();

SEE ALSO
    See POE::Resource for general discussion about resources and the classes
    that manage them.

BUGS
    None known.

AUTHORS & COPYRIGHTS
    Please see POE for more information about authors and contributors.

Generated by phpMan Author: Che Dong On Apache Under GNU General Public License - MarkDown Format
2026-05-21 22:10 @216.73.216.105 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)