NAME

       sem_destroy - destroy an unnamed semaphore (REALTIME)

SYNOPSIS

       #include <semaphore.h>

       int sem_destroy(sem_t *sem);

DESCRIPTION

       The  sem_destroy()  function  shall destroy the unnamed semaphore indicated by sem. Only a
       semaphore that was created using sem_init() may  be  destroyed  using  sem_destroy();  the
       effect  of  calling  sem_destroy()  with  a  named  semaphore  is undefined. The effect of
       subsequent use of the semaphore sem is undefined until sem  is  reinitialized  by  another
       call to sem_init().

       It  is  safe  to  destroy  an  initialized  semaphore  upon which no threads are currently
       blocked. The effect of destroying a semaphore  upon  which  other  threads  are  currently
       blocked is undefined.

RETURN VALUE

       Upon  successful  completion,  a value of zero shall be returned. Otherwise, a value of -1
       shall be returned and errno set to indicate the error.

ERRORS

       The sem_destroy() function shall fail if:

       EINVAL The sem argument is not a valid semaphore.

       The sem_destroy() function may fail if:

       EBUSY  There are currently processes blocked on the semaphore.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The sem_destroy() 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() , 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 .