pthread_mutex.h

Mutual exclusion.

Note

Do not include this header file directly, but pthread.h.

mutex_t pthread_mutex_t

Pthread mutexes are quite the same as RIOT mutexes.

Recursive locking is not supported. A thread can unlock a mutex even if it does not hold it.

int pthread_mutex_init(pthread_mutex.h::pthread_mutex_t * mutex, const pthread_mutexattr_t * mutexattr)

Initialize a mutex.

A zeroed out datum is initialized.

Parameters

mutex:Mutex to initialize. mutexattr:Unused.

Return values

• 0 on success. -1 iff mutex == NULL.

int pthread_mutex_destroy(pthread_mutex.h::pthread_mutex_t * mutex)

Destroy a mutex.

This is currently a no-op. Destroying a mutex locked is undefined behavior.

Parameters

mutex:Datum to destroy.

Return values

• 0, this invocation is a no-op that cannot fail.

int pthread_mutex_trylock(pthread_mutex.h::pthread_mutex_t * mutex)

Try to lock a mutex.

This function won’t block.

Parameters

mutex:Mutex to lock, must be initialized.

Return values

• 0 if you hold the mutex now. +1 if the mutex already was locked. -1 if you managed to supply NULL.

int pthread_mutex_lock(pthread_mutex.h::pthread_mutex_t * mutex)

Lock and hold a mutex.

This invocation may block if the mutex was locked.

Parameters

mutex:Mutex to lock, must be initialized.

Return values

• -1 iff you managed to supply NULL. 0 otherwise, you hold the mutex now.

int pthread_mutex_timedlock(pthread_mutex.h::pthread_mutex_t * mutex, const struct timespec * abstime)

Not implemented, yet.

Will cause a linktime error …

Parameters

mutex:The unused mutex. abstime:The used absolute time.

Return values

• Well … you’ll get a link time error, so nothing will be returned.

int pthread_mutex_unlock(pthread_mutex.h::pthread_mutex_t * mutex)

Unlock a mutex.

It is possible to unlock a mutex that you don’t hold. It is possible to unlock a mutex that is not held at all. The mutex can still be locked afterwards if there were threads queuing for this mutex.

Parameters

mutex:Mutex to unlock, must be initialized.

Return values

• -1 iff you managed to supply NULL. 0 otherwise.

int pthread_mutex_getprioceiling(const pthread_mutex.h::pthread_mutex_t * mutex, int * prioceiling)

Not implemented, yet.

Will cause a linktime error …

Parameters

mutex:The unused mutex. prioceiling:Unused.

Return values

• Well … you’ll get a link time error, so nothing will be returned.

int pthread_mutex_setprioceiling(pthread_mutex.h::pthread_mutex_t * mutex, int prioceiling, int * old_ceiling)

Not implemented, yet.

Will cause a linktime error …

Parameters

mutex:The unused mutex. prioceiling:Unused. old_ceiling:Unused.

Return values

• Well … you’ll get a link time error, so nothing will be returned.