mirror of https://github.com/mkerrisk/man-pages
79 lines
2.4 KiB
Groff
79 lines
2.4 KiB
Groff
'\" t
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.TH SEM_DESTROY 3 2006-03-25 "Linux" "Linux Programmer's Manual"
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.SH NAME
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sem_destroy \- destroy an unnamed semaphore
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.SH SYNOPSIS
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.nf
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.B #include <semaphore.h>
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.sp
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.BI "int sem_destroy(sem_t *" sem );
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.fi
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.sp
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Link with \fI\-lrt\fP or \fI\-pthread\fP.
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.SH DESCRIPTION
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.BR sem_destroy ()
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destroys the unnamed semaphore at the address pointed to by
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.IR sem .
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Only a semaphore that has been initialized by
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.BR sem_init (3)
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should be destroyed using
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.BR sem_destroy ().
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Destroying a semaphore that other processes or threads are
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currently blocked on (in
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.BR sem_wait (3))
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produces undefined behavior.
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Using a semaphore that has been destroyed produces undefined results,
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until the semaphore has been reinitialized using
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.BR sem_init (3).
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.SH RETURN VALUE
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.BR sem_destroy ()
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returns 0 on success;
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on error, \-1 is returned, and
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.I errno
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is set to indicate the error.
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.SH ERRORS
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.TP
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.B EINVAL
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.I sem
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is not a valid semaphore.
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.SH CONFORMING TO
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POSIX.1-2001.
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.SH NOTES
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An unnamed semaphore should be destroyed with
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.BR sem_destroy ()
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before the memory in which it is located is deallocated.
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Failure to do this can result in resource leaks on some implementations.
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.\" But not on NPTL, where sem_destroy () is a no-op..
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.SH "SEE ALSO"
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.BR sem_init (3),
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.BR sem_post (3),
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.BR sem_wait (3),
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.BR sem_overview (7)
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