NAME    [Toc]    [Back]

       pthread_mutex_unlock - Unlocks the specified mutex

SYNOPSIS    [Toc]    [Back]

       #include <pthread.h>

       int pthread_mutex_unlock(
               pthread_mutex_t *mutex );

LIBRARY    [Toc]    [Back]

       DECthreads POSIX 1003.1c Library (libpthread.so)

STANDARDS    [Toc]    [Back]

       Interfaces  documented  on  this reference page conform to
       industry standards as follows:

       IEEE Std 1003.1c-1995, POSIX  System  Application  Program
       Interface

PARAMETERS    [Toc]    [Back]

       Mutex to be unlocked.

DESCRIPTION    [Toc]    [Back]

       This  routine  unlocks  the  mutex  specified by the mutex
       argument.

       This routine behaves as follows, based on the type of  the
       specified  mutex:  For  a  normal,  default, or errorcheck
       mutex: if the mutex is owned by the calling thread, it  is
       unlocked  with  no current owner. Further, for a normal or
       default mutex: if the mutex is not locked or is locked  by
       another  thread, this routine can also return [EPERM], but
       this is not guaranteed.  For an errorcheck mutex:  if  the
       mutex  is  not locked or is locked by another thread, this
       routine returns [EPERM].  For a recursive  mutex:  if  the
       mutex  is  owned  by the calling thread, the lock count is
       decremented. The mutex remains locked and owned until  the
       lock  count  reaches zero (0). When the lock count reaches
       zero, the mutex becomes unlocked with no current owner.

       If one or more threads are waiting to lock  the  specified
       mutex, and the mutex becomes unlocked, this routine causes
       one thread to unblock and to try to acquire the mutex. The
       scheduling  policy  is  used  to determine which thread to
       unblock. For  the  SCHED_FIFO  and  SCHED_RR  policies,  a
       blocked  thread  is chosen in priority order, using firstin/first-out
 within priorities.  Note that the mutex might
       not  be  acquired by the awakened thread if any other running
 thread attempts to lock the mutex first.

       On Tru64 UNIX, if a signal is delivered to a thread  waiting
  for a mutex, upon return from the signal handler, the
       thread resumes waiting for the mutex  as  if  it  was  not
       interrupted.

RETURN VALUES    [Toc]    [Back]

       If  an  error  condition  occurs,  this routine returns an
       integer value  indicating  the  type  of  error.  Possible
       return  values are as follows: Successful completion.  The
       value specified for mutex is invalid.  The calling  thread
       does not own the mutex.

ERRORS    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

       Functions:                   pthread_mutexattr_settype(3),
       pthread_mutex_destroy(3),           pthread_mutex_init(3),
       pthread_mutex_lock(3), pthread_mutex_trylock(3)

       Manuals: Guide to DECthreads and Programmer's Guide



                                          pthread_mutex_unlock(3)