pthread_mutex_destroy(3t) [hpux man page]

pthread_mutex_init(3T)													    pthread_mutex_init(3T)

NAME

       pthread_mutex_init(), pthread_mutex_destroy() - initialize or destroy a mutex

SYNOPSIS

PARAMETERS

	      mutex	Pointer to the mutex to be initialized or destroyed.

	      attr	Pointer to the attributes object that defines the characteristics of the mutex to be initialized.  If the pointer is NULL,
			default attributes are used.

DESCRIPTION

       The function initializes the mutex referenced by mutex with the attributes attr.   If  the  parameter  attr  is	NULL,  the  default  mutex
       attributes are used.  See pthread_mutexattr_init(3T) for a list of default mutex attributes.  After successful initialization, the mutex is
       initialized, unlocked, and ready to be used in mutex operations.  A mutex should be initialized only once  or  the  resulting  behavior	is
       undefined.  The function provides a way to ensure that a mutex is initialized only once.

       The macro can be used to initialize mutexes that are statically allocated.  These mutexes will be initialized with default attributes.  The
       function does not need to be called for statically initialized mutexes.

       If the process-shared attribute in the mutex attributes object referenced by attr is defined as the mutex must be allocated such  that  the
       processes  sharing  the	mutex have access to it.  This may be done through the memory-mapping functions (see mmap(2)) or the shared memory
       functions (see shmget(2)).

       The function destroys the mutex referenced by mutex.  This function may set mutex to an invalid value.  The destroyed mutex can	be  reini-
       tialized using the function If the mutex is used after destruction in any mutex call, the resulting behavior is undefined.

       A mutex should be destroyed only when it is unlocked.  Destroying a mutex that is currently being used results in undefined behavior.

RETURN VALUE

       Upon successful completion, and return zero.  Otherwise, an error number is returned to indicate the error (the variable is not set).

ERRORS

       If any of the following occur, the function returns the corresponding error number:

	      The necessary resources (other than memory) to initialize
			     mutex were not available.

	      mutex	     is an already initialized mutex.  However, getting for reinitializing the mutex cannot be expected all the time since
			     the behavior of reinitializing the mutex is undefined.

	      mutex	     points to an illegal address.

	      The value specified by
			     mutex or attr is invalid.

	      There is insufficient memory available in which to initialize
			     mutex.

	      The caller does not have the necessary permission to perform the
			     mutex initialization.

       If any of the following occur, the function returns the corresponding error number:

	      mutex	     is currently locked or in use by another thread.

	      mutex	     is not a valid mutex.

WARNINGS

       The space for the mutex must be allocated before calling Undefined behavior will result if the process-shared attribute of attr is and  the
       space allocated for the mutex is not accessible to cooperating threads.

AUTHOR

       and were derived from the IEEE POSIX P1003.1c standard.

SEE ALSO

       pthread_mutex_lock(3T), pthread_mutex_trylock(3T), pthread_mutex_unlock(3T).

STANDARDS CONFORMANCE

								  Pthread Library					    pthread_mutex_init(3T)

pthread_mutex_init(3C)													    pthread_mutex_init(3C)

NAME

       pthread_mutex_init, pthread_mutex_destroy - initialize or destroy a mutex

SYNOPSIS

       cc -mt [ flag... ] file... -lpthread [ library... ]
       #include <pthread.h>

       int pthread_mutex_init(pthread_mutex_t *restrict mutex, const pthread_mutexattr_t *restrict attr);

       int pthread_mutex_destroy(pthread_mutex_t *mutex);
       pthread_mutex_t mutex= PTHREAD_MUTEX_INITIALIZER

       The  pthread_mutex_init()  function  initializes  the  mutex  referenced  by mutex with attributes specified by attr. If attr is  NULL, the
       default mutex attributes are used; the effect is the same as passing the address of a default mutex attributes object. Upon successful ini-
       tialization, the state of the mutex becomes initialized and unlocked.

       Attempting to initialize an already initialized mutex results in undefined behavior.

       The  pthread_mutex_destroy()  function destroys the mutex object referenced by mutex; the mutex object becomes, in effect, uninitialized. A
       destroyed mutex object can be re-initialized using pthread_mutex_init(); the results of otherwise referencing the object after it has  been
       destroyed are undefined.

       It is safe to destroy an initialized mutex that is unlocked. Attempting to destroy a locked mutex results in undefined behavior.

       In  cases  where  default  mutex attributes are appropriate, the macro PTHREAD_MUTEX_INITIALIZER can be used to initialize mutexes that are
       statically allocated. The effect is equivalent to dynamic initialization by a call to pthread_mutex_init() with parameter attr specified as
       NULL, except that no error checks are performed.

       If successful, the pthread_mutex_init() and pthread_mutex_destroy() functions return  0. Otherwise, an error number is returned to indicate
       the error.

       The pthread_mutex_init() function will fail if:

       EAGAIN	       The system lacked the necessary resources (other than memory) to initialize another mutex.

       EBUSY	       An attempt was detected to  re-initialize the object referenced by mutex,  a robust mutex previously  initialized  but  not
		       yet destroyed.

       EINVAL	       The value specified by attr has not been initialized using pthread_mutexattr_init(3C).

       EINVAL	       An attempt was made to initialize mutex to be robust and not PTHREAD_PRIO_INHERIT.

       EINVAL	       An  attempt  was made to initalize mutex to be PTHREAD_PRIO_INHERIT or PTHREAD_PRIO_PROTECT and the type of the mutex to be
		       PTHREAD_MUTEX_ERRORCHECK or PTHREAD_MUTEX_RECURSIVE.

       EINVAL	       An attpemt was made to initalize mutex to be PTHREAD_PROCESS_SHARED and the type of the mutex  to  be  PTHREAD_MUTEX_RECUR-
		       SIVE.

       EINVAL	       The process-shared attribute associated with attr is invalid.

       ENOMEM	       Insufficient memory exists to initialize the mutex.

       EPERM	       The caller does not have the privilege to perform the operation.

       The pthread_mutex_init() function may fail if:

       EBUSY	       An  attempt  was  detected  to  re-initialize  the  object  referenced by mutex, a mutex previously initialized but not yet
		       destroyed.

       EINVAL	       The value specified by attr or mutex is invalid.

       The pthread_mutex_destroy() function may fail if:

       EBUSY	       An attempt was detected to destroy the object referenced by mutex while it is locked  or  referenced  (for  example,  while
		       being used in a pthread_cond_wait(3C) or pthread_cond_timedwait(3C)) by another thread.

       EINVAL	       The value specified by mutex is invalid.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

       pthread_cond_timedwait(3C),   pthread_cond_wait(3C),  pthread_mutex_getprioceiling(3C),	pthread_mutex_lock(3C),  pthread_mutex_unlock(3C),
       pthread_mutex_setprioceiling(3C), pthread_mutex_trylock(3C), pthread_mutexattr_init(3C),  pthread_mutexattr_getpshared(3C),  pthread_mutex-
       attr_setpshared(3C) attributes(5), mutex(5), standards(5)

								    23 Mar 2005 					    pthread_mutex_init(3C)