sem_close(3p) - phpMan

SEM_CLOSE(3P)              POSIX Programmer's Manual             SEM_CLOSE(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       sem_close - close a named semaphore (REALTIME)
SYNOPSIS
       #include <semaphore.h>
       int sem_close(sem_t *sem);

DESCRIPTION
       The sem_close() function shall indicate that  the  calling  process  is
       finished  using  the  named  semaphore indicated by sem. The effects of
       calling  sem_close()  for  an  unnamed  semaphore   (one   created   by
       sem_init())  are  undefined.  The sem_close() function shall deallocate
       (that is, make available for reuse by a subsequent sem_open()  by  this
       process)  any  system resources allocated by the system for use by this
       process for this semaphore. The effect of subsequent use of  the  sema-
       phore  indicated  by sem by this process is undefined. If the semaphore
       has not been removed with  a  successful  call  to  sem_unlink(),  then
       sem_close()  has  no  effect  on  the  state  of the semaphore.  If the
       sem_unlink() function has been successfully invoked for name after  the
       most  recent  call  to sem_open() with O_CREAT for this semaphore, then
       when all processes that have opened the semaphore close it,  the  sema-
       phore is no longer accessible.
RETURN VALUE
       Upon  successful  completion, a value of zero shall be returned. Other-
       wise, a value of -1 shall be returned and errno  set  to  indicate  the
       error.
ERRORS
       The sem_close() function shall fail if:
       EINVAL The sem argument is not a valid semaphore descriptor.

       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       The  sem_close() function is part of the Semaphores option and need not
       be available on all implementations.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       semctl(), semget(), semop(), sem_init(), sem_open(), sem_unlink(),  the
       Base Definitions volume of IEEE Std 1003.1-2001, <semaphore.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                        SEM_CLOSE(3P)