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IPC::Semaphore.3
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.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "IPC::Semaphore 3" .TH IPC::Semaphore 3 2020-12-28 "perl v5.38.0" "Perl Programmers Reference Guide" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME IPC::Semaphore \- SysV Semaphore IPC object class .SH SYNOPSIS .IX Header "SYNOPSIS" .Vb 2 \& use IPC::SysV qw(IPC_PRIVATE S_IRUSR S_IWUSR IPC_CREAT); \& use IPC::Semaphore; \& \& $sem = IPC::Semaphore\->new(IPC_PRIVATE, 10, S_IRUSR | S_IWUSR | IPC_CREAT); \& \& $sem\->setall( (0) x 10); \& \& @sem = $sem\->getall; \& \& $ncnt = $sem\->getncnt; \& \& $zcnt = $sem\->getzcnt; \& \& $ds = $sem\->stat; \& \& $sem\->remove; .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" A class providing an object based interface to SysV IPC semaphores. .SH METHODS .IX Header "METHODS" .IP "new ( KEY , NSEMS , FLAGS )" 4 .IX Item "new ( KEY , NSEMS , FLAGS )" Create a new semaphore set associated with \f(CW\*(C`KEY\*(C'\fR. \f(CW\*(C`NSEMS\*(C'\fR is the number of semaphores in the set. A new set is created if .RS 4 .IP \(bu 4 \&\f(CW\*(C`KEY\*(C'\fR is equal to \f(CW\*(C`IPC_PRIVATE\*(C'\fR .IP \(bu 4 \&\f(CW\*(C`KEY\*(C'\fR does not already have a semaphore identifier associated with it, and \f(CW\*(C`\fR\f(CIFLAGS\fR\f(CW & IPC_CREAT\*(C'\fR is true. .RE .RS 4 .Sp On creation of a new semaphore set \f(CW\*(C`FLAGS\*(C'\fR is used to set the permissions. Be careful not to set any flags that the Sys V IPC implementation does not allow: in some systems setting execute bits makes the operations fail. .RE .IP getall 4 .IX Item "getall" Returns the values of the semaphore set as an array. .IP "getncnt ( SEM )" 4 .IX Item "getncnt ( SEM )" Returns the number of processes waiting for the semaphore \f(CW\*(C`SEM\*(C'\fR to become greater than its current value .IP "getpid ( SEM )" 4 .IX Item "getpid ( SEM )" Returns the process id of the last process that performed an operation on the semaphore \f(CW\*(C`SEM\*(C'\fR. .IP "getval ( SEM )" 4 .IX Item "getval ( SEM )" Returns the current value of the semaphore \f(CW\*(C`SEM\*(C'\fR. .IP "getzcnt ( SEM )" 4 .IX Item "getzcnt ( SEM )" Returns the number of processes waiting for the semaphore \f(CW\*(C`SEM\*(C'\fR to become zero. .IP id 4 .IX Item "id" Returns the system identifier for the semaphore set. .IP "op ( OPLIST )" 4 .IX Item "op ( OPLIST )" \&\f(CW\*(C`OPLIST\*(C'\fR is a list of operations to pass to \f(CW\*(C`semop\*(C'\fR. \f(CW\*(C`OPLIST\*(C'\fR is a concatenation of smaller lists, each which has three values. The first is the semaphore number, the second is the operation and the last is a flags value. See \fBsemop\fR\|(2) for more details. For example .Sp .Vb 4 \& $sem\->op( \& 0, \-1, IPC_NOWAIT, \& 1, 1, IPC_NOWAIT \& ); .Ve .IP remove 4 .IX Item "remove" Remove and destroy the semaphore set from the system. .IP "set ( STAT )" 4 .IX Item "set ( STAT )" .PD 0 .IP "set ( NAME => VALUE [, NAME => VALUE ...] )" 4 .IX Item "set ( NAME => VALUE [, NAME => VALUE ...] )" .PD \&\f(CW\*(C`set\*(C'\fR will set the following values of the \f(CW\*(C`stat\*(C'\fR structure associated with the semaphore set. .Sp .Vb 3 \& uid \& gid \& mode (only the permission bits) .Ve .Sp \&\f(CW\*(C`set\*(C'\fR accepts either a stat object, as returned by the \f(CW\*(C`stat\*(C'\fR method, or a list of \fIname\fR\-\fIvalue\fR pairs. .IP "setall ( VALUES )" 4 .IX Item "setall ( VALUES )" Sets all values in the semaphore set to those given on the \f(CW\*(C`VALUES\*(C'\fR list. \&\f(CW\*(C`VALUES\*(C'\fR must contain the correct number of values. .IP "setval ( N , VALUE )" 4 .IX Item "setval ( N , VALUE )" Set the \f(CW\*(C`N\*(C'\fRth value in the semaphore set to \f(CW\*(C`VALUE\*(C'\fR .IP stat 4 .IX Item "stat" Returns an object of type \f(CW\*(C`IPC::Semaphore::stat\*(C'\fR which is a sub-class of \&\f(CW\*(C`Class::Struct\*(C'\fR. It provides the following fields. For a description of these fields see your system documentation. .Sp .Vb 8 \& uid \& gid \& cuid \& cgid \& mode \& ctime \& otime \& nsems .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" IPC::SysV, Class::Struct, \fBsemget\fR\|(2), \fBsemctl\fR\|(2), \fBsemop\fR\|(2) .SH AUTHORS .IX Header "AUTHORS" Graham Barr <gbarr@pobox.com>, Marcus Holland-Moritz <mhx@cpan.org> .SH COPYRIGHT .IX Header "COPYRIGHT" Version 2.x, Copyright (C) 2007\-2013, Marcus Holland-Moritz. .PP Version 1.x, Copyright (c) 1997, Graham Barr. .PP This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.