disabled /ˆl–ßi~””ÂXÔåÆEpN©‹Fÿ¿ ƒq—_‹uÐb &=LV[(ÃÂàpackage Thread::Semaphore; use strict; use warnings; our $VERSION = '2.12'; $VERSION = eval $VERSION; use threads::shared; use Scalar::Util 1.10 qw(looks_like_number); # Predeclarations for internal functions my ($validate_arg); # Create a new semaphore optionally with specified count (count defaults to 1) sub new { my $class = shift; my $val :shared = 1; if (@_) { $val = shift; if (! defined($val) || ! looks_like_number($val) || (int($val) != $val)) { require Carp; $val = 'undef' if (! defined($val)); Carp::croak("Semaphore initializer is not an integer: $val"); } } return bless(\$val, $class); } # Decrement a semaphore's count (decrement amount defaults to 1) sub down { my $sema = shift; my $dec = @_ ? $validate_arg->(shift) : 1; lock($$sema); cond_wait($$sema) until ($$sema >= $dec); $$sema -= $dec; } # Decrement a semaphore's count only if count >= decrement value # (decrement amount defaults to 1) sub down_nb { my $sema = shift; my $dec = @_ ? $validate_arg->(shift) : 1; lock($$sema); my $ok = ($$sema >= $dec); $$sema -= $dec if $ok; return $ok; } # Decrement a semaphore's count even if the count goes below 0 # (decrement amount defaults to 1) sub down_force { my $sema = shift; my $dec = @_ ? $validate_arg->(shift) : 1; lock($$sema); $$sema -= $dec; } # Increment a semaphore's count (increment amount defaults to 1) sub up { my $sema = shift; my $inc = @_ ? $validate_arg->(shift) : 1; lock($$sema); ($$sema += $inc) > 0 and cond_broadcast($$sema); } ### Internal Functions ### # Validate method argument $validate_arg = sub { my $arg = shift; if (! defined($arg) || ! looks_like_number($arg) || (int($arg) != $arg) || ($arg < 1)) { require Carp; my ($method) = (caller(1))[3]; $method =~ s/Thread::Semaphore:://; $arg = 'undef' if (! defined($arg)); Carp::croak("Argument to semaphore method '$method' is not a positive integer: $arg"); } return $arg; }; 1; =head1 NAME Thread::Semaphore - Thread-safe semaphores =head1 VERSION This document describes Thread::Semaphore version 2.12 =head1 SYNOPSIS use Thread::Semaphore; my $s = Thread::Semaphore->new(); $s->down(); # Also known as the semaphore P operation. # The guarded section is here $s->up(); # Also known as the semaphore V operation. # Decrement the semaphore only if it would immediately succeed. if ($s->down_nb()) { # The guarded section is here $s->up(); } # Forcefully decrement the semaphore even if its count goes below 0. $s->down_force(); # The default value for semaphore operations is 1 my $s = Thread::Semaphore->new($initial_value); $s->down($down_value); $s->up($up_value); if ($s->down_nb($down_value)) { ... $s->up($up_value); } $s->down_force($down_value); =head1 DESCRIPTION Semaphores provide a mechanism to regulate access to resources. Unlike locks, semaphores aren't tied to particular scalars, and so may be used to control access to anything you care to use them for. Semaphores don't limit their values to zero and one, so they can be used to control access to some resource that there may be more than one of (e.g., filehandles). Increment and decrement amounts aren't fixed at one either, so threads can reserve or return multiple resources at once. =head1 METHODS =over 8 =item ->new() =item ->new(NUMBER) C creates a new semaphore, and initializes its count to the specified number (which must be an integer). If no number is specified, the semaphore's count defaults to 1. =item ->down() =item ->down(NUMBER) The C method decreases the semaphore's count by the specified number (which must be an integer >= 1), or by one if no number is specified. If the semaphore's cou