Win32::Semaphore - Use Win32 semaphore objects from Perl
This document describes version 1.09 of Win32::Semaphore, released January 14, 2012 as part of Win32-IPC version 1.09.
require Win32::Semaphore; $sem = Win32::Semaphore->new($initial,$maximum,$name); $sem->wait;
This module allows access to Win32 semaphore objects. The
wait method and
wait_any functions are inherited from the Win32::IPC module.
Constructor for a new semaphore object.
$initial is the initial count, and
$maximum is the maximum count for the semaphore. If
$name is omitted or
undef, creates an unnamed semaphore object.
$name signifies an existing semaphore object, then
$maximum are ignored and the object is opened. If this happens,
$^E will be set to 183 (ERROR_ALREADY_EXISTS).
Constructor for opening an existing semaphore object.
Increment the count of
$increment (default 1). If
$increment plus the semaphore's current count is more than its maximum count, the count is not changed. Returns true if the increment is successful, or zero if it fails (additional error information can be found in
The semaphore's count (before incrementing) is stored in the second argument (if any).
It is not necessary to wait on a semaphore before calling
release, but you'd better know what you're doing.
$semaphore's count to be nonzero, then decrement it by 1. See Win32::IPC.
Win32::Semaphore still supports the ActiveWare syntax, but its use is deprecated.
$SemObject = Win32::Semaphore->new($Initial,$Max,$Name) instead.
$SemObject = Win32::Semaphore->open($Name) instead.
Win32::Semaphore requires no configuration files or environment variables.
It runs under 32-bit or 64-bit Microsoft Windows, either natively or under Cygwin.
Prior to version 1.06, the Win32 IPC modules treated
undef values differently. In version 1.06 and later, passing
undef as the value of an optional parameter is the same as omitting that parameter. In previous versions,
undef was interpreted as either the empty string or 0 (along with a warning about "Use of uninitialized value...").
Signal handlers will not be called during the
wait method. See "BUGS AND LIMITATIONS" in Win32::IPC for details.
Christopher J. Madsen
<perl AT cjmweb.net>
Please report any bugs or feature requests to
<bug-Win32-IPC AT rt.cpan.org> or through the web interface at http://rt.cpan.org/Public/Bug/Report.html?Queue=Win32-IPC.
You can follow or contribute to Win32-IPC's development at http://github.com/madsen/win32-ipc.
Loosely based on the original module by ActiveWare Internet Corp., http://www.ActiveState.com
Copyright 1998-2012 Christopher J. Madsen
Created: 3 Feb 1998 from the ActiveWare version (c) 1995 Microsoft Corporation. All rights reserved. Developed by ActiveWare Internet Corp., http://www.ActiveState.com
Other modifications (c) 1997 by Gurusamy Sarathy <gsar AT cpan.org>
This module is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
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