atomic_dec_and_mutex_lock(9) [centos man page]

ATOMIC_DEC_AND_MUTEX(9) 					Mutex API reference					   ATOMIC_DEC_AND_MUTEX(9)

NAME

       atomic_dec_and_mutex_lock - return holding mutex if we dec to 0

SYNOPSIS

       int atomic_dec_and_mutex_lock(atomic_t * cnt, struct mutex * lock);

ARGUMENTS

       cnt
	   the atomic which we are to dec

       lock
	   the mutex to return holding if we dec to 0

DESCRIPTION

       return true and hold lock if we dec to 0, return false otherwise

AUTHOR

       Rusty Russell <rusty@rustcorp.com.au>
	   Author.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   ATOMIC_DEC_AND_MUTEX(9)

pthread_mutex_unlock(3) 				     Library Functions Manual					   pthread_mutex_unlock(3)

NAME

       pthread_mutex_unlock - Unlocks the specified mutex.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int   pthread_mutex_unlock(
			      pthread_mutex_t	*mutex);

STANDARDS

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

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

PARAMETERS

       Mutex to be unlocked.

DESCRIPTION

       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 first-in/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

       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

       None

RELATED INFORMATION

       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

       delim off

															   pthread_mutex_unlock(3)