cc –mt [ flag... ] file... –lpthread [ -lrt library... ] #include <pthread.h>int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr);
pthread_mutex_t mutex= PTHREAD_MUTEX_INITIALIZERint pthread_mutex_destroy(pthread_mutex_t *mutex);
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 initialization, 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:
The system lacked the necessary resources (other than memory) to initialize another mutex.
An attempt was detected to re-initialize the object referenced by mutex, a robust mutex previously initialized but not yet destroyed.
The value specified by attr has not been initialized using pthread_mutexattr_init(3THR).
An attempt was made to initialize mutex to be robust and not PTHREAD_PRIO_INHERIT.
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.
An attpemt was made to initalize mutex to be PTHREAD_PROCESS_SHARED and the type of the mutex to be PTHREAD_MUTEX_RECURSIVE.
The process-shared attribute associated with attr is invalid.
Insufficient memory exists to initialize the mutex.
The caller does not have the privilege to perform the operation.
The pthread_mutex_init() function may fail if:
An attempt was detected to re-initialize the object referenced by mutex, a mutex previously initialized but not yet destroyed.
The value specified by attr or mutex is invalid.
The pthread_mutex_destroy() function may fail if:
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|
mutex(3THR), pthread_cond_timedwait(3THR), pthread_cond_wait(3THR), pthread_mutex_getprioceiling(3THR), pthread_mutex_lock(3THR), pthread_mutex_unlock(3THR), pthread_mutex_setprioceiling(3THR), pthread_mutex_trylock(3THR), pthread_mutexattr_init(3THR), pthread_mutexattr_getpshared(3THR), pthread_mutexattr_setpshared(3THR) attributes(5), standards(5)