PTHREAD_MUTEX(3) | Library Functions Manual | PTHREAD_MUTEX(3) |
pthread_mutex
,
pthread_mutex_init
,
pthread_mutex_destroy
,
pthread_mutex_lock
,
pthread_mutex_trylock
,
pthread_mutex_unlock
,
pthread_mutex_timedlock
,
pthread_mutex_getprioceiling
,
pthread_mutex_setprioceiling
—
#include <pthread.h>
int
pthread_mutex_init
(pthread_mutex_t
* restrict mutex, const
pthread_mutexattr_t * restrict attr);
pthread_mutex_t mutex =
PTHREAD_MUTEX_INITIALIZER
;
int
pthread_mutex_destroy
(pthread_mutex_t
*mutex);
int
pthread_mutex_lock
(pthread_mutex_t
*mutex);
int
pthread_mutex_trylock
(pthread_mutex_t
*mutex);
int
pthread_mutex_unlock
(pthread_mutex_t
*mutex);
int
pthread_mutex_timedlock
(pthread_mutex_t
*__restrict mutex, const
struct timespec *__restrict timeout);
int
pthread_mutex_getprioceiling
(const
pthread_mutex_t * __restrict mutex,
int * __restrict
prioceiling);
int
pthread_mutex_setprioceiling
(pthread_mutex_t
* __restrict mutex, int
prioceiling, int *
__restrict old_ceiling);
pthread_mutex_init
() function creates a new mutex,
with attributes specified with attr. If
attr is NULL
, the default
attributes are used.
The macro PTHREAD_MUTEX_INITIALIZER
can be
used to initialize a mutex when the default attributes are appropriate and
the mutex can be statically allocated. The behavior is similar to
pthread_mutex_init
() with attr
specified as NULL
, except that no error checking is
done.
The pthread_mutex_destroy
() function frees
the resources allocated for mutex. It is possible to
reinitialize a destroyed mutex, but undefined behavior may follow if the
destroyed object is otherwise referenced.
The pthread_mutex_lock
() function locks
mutex. If the mutex is already locked, the calling
thread will block until the mutex becomes available. The error conditions
may vary depending on the type of the mutex; see
pthread_mutexattr(3)
for additional details.
The pthread_mutex_trylock
() function locks
mutex. If the mutex is already locked,
pthread_mutex_trylock
() will not block waiting for
the mutex, but will return an error condition.
The pthread_mutex_unlock
() function
unlocks an acquired mutex. When operating with the
default mutex type, undefined behavior follows if a thread tries to unlock a
mutex that has not been locked by it, or if a thread tries to release a
mutex that is already unlocked.
The pthread_mutex_timedlock
() function
shall lock the mutex object referenced by mutex. If
the mutex is already locked, the calling thread shall block until the mutex
becomes available in the pthread_mutex_lock
()
function. If the mutex cannot be locked without waiting for another thread
to unlock the mutex, this wait shall be terminated when the specified
timeout expires. The timeout shall expire when the absolute time specified
by timeout passes, as measured by the clock on which
timeouts are based.
The pthread_mutex_getprioceiling
()
function shall return the current priority ceiling of the mutex.
The pthread_mutex_setprioceiling
()
function shall either lock the mutex if it is unlocked, or block until it
can sucessfully lock the mutex, then it shall change the mutex's priority
ceiling and release the mutex. When the change is successful, the previous
value of the priority ceiling shall be returned in
old_ceiling. The process of locking the mutex need not
adhere to the priority protect protocol. If
pthread_mutex_setprioceiling
() function fails, the
mutex priority ceiling shall not be changed.
pthread_mutex_init
() may fail if:
EAGAIN
]EINVAL
]ENOMEM
]pthread_mutex_destroy
() may fail if:
pthread_mutex_lock
() may fail if:
EDEADLK
]EINVAL
]pthread_mutex_trylock
() may fail if:
pthread_mutex_unlock
() may fail if:
EINVAL
]EPERM
]pthread_mutex_timedlock
() may fail if:
EINVAL
]PTHREAD_PRIO_PROTECT
and the calling thread's
priority is higher than the mutex current priority ceiling; or the process
or thread would have blocked, and the timeout
parameter specified a nanoseconds field value less than zero or greater
than or equal to 1000 million.ETIMEDOUT
]The pthread_mutex_getprioceiling
() and
pthread_mutex_setprioceiling
() functions may fail
if:
June 12, 2016 | NetBSD 9.2 |