man3/sem_destroy.3

   1 '\" t
   2 .\" Hey Emacs! This file is -*- nroff -*- source.
   3 .\"
   4 .\" Copyright (C) 2006 Michael Kerrisk <mtk-manpages@gmx.net>
   5 .\"
   6 .\" Permission is granted to make and distribute verbatim copies of this
   7 .\" manual provided the copyright notice and this permission notice are
   8 .\" preserved on all copies.
   9 .\"
  10 .\" Permission is granted to copy and distribute modified versions of this
  11 .\" manual under the conditions for verbatim copying, provided that the
  12 .\" entire resulting derived work is distributed under the terms of a
  13 .\" permission notice identical to this one.
  14 .\"
  15 .\" Since the Linux kernel and libraries are constantly changing, this
  16 .\" manual page may be incorrect or out-of-date.  The author(s) assume no
  17 .\" responsibility for errors or omissions, or for damages resulting from
  18 .\" the use of the information contained herein.
  19 .\"
  20 .\" Formatted or processed versions of this manual, if unaccompanied by
  21 .\" the source, must acknowledge the copyright and authors of this work.
  22 .\"
  23 .TH SEM_DESTROY 3 2006-03-25 "Linux" "Linux Programmer's Manual"
  24 .SH NAME
  25 sem_destroy \- destroy an unnamed semaphore
  26 .SH SYNOPSIS
  27 .nf
  28 .B #include <semaphore.h>
  29 .sp
  30 .BI "int sem_destroy(sem_t *" sem );
  31 .fi
  32 .SH DESCRIPTION
  33 .BR sem_destroy ()
  34 destroys the unnamed semaphore at the address pointed to by
  35 .IR sem .
  36
  37 Only a semaphore that has been initialized by
  38 .BR sem_init (3)
  39 should be destroyed using
  40 .BR sem_destroy ().
  41
  42 Destroying a semaphore that other processes or threads are
  43 currently blocked on (in
  44 .BR sem_wait (3))
  45 produces undefined behavior.
  46
  47 Using a semaphore that has been destroyed produces undefined results,
  48 until the semaphore has been reinitialized using
  49 .BR sem_init (3).
  50 .SH RETURN VALUE
  51 .BR sem_destroy ()
  52 returns 0 on success;
  53 on error, \-1 is returned, and
  54 .I errno
  55 is set to indicate the error.
  56 .SH ERRORS
  57 .TP
  58 .B EINVAL
  59 .I sem
  60 is not a valid semaphore.
  61 .SH CONFORMING TO
  62 POSIX.1-2001.
  63 .SH NOTES
  64 An unnamed semaphore should be destroyed with
  65 .BR sem_destroy ()
  66 before the memory in which it is located is deallocated.
  67 Failure to do this can result in resource leaks on some implementations.
  68 .\" But not on NPTL, where sem_destroy () is a no-op..
  69 .SH "SEE ALSO"
  70 .BR sem_init (3),
  71 .BR sem_post (3),
  72 .BR sem_wait (3),
  73 .BR sem_overview (7)