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mutex_lock(9) [centos man page]

MUTEX_LOCK(9)							Mutex API reference						     MUTEX_LOCK(9)

NAME
mutex_lock - acquire the mutex SYNOPSIS
void __sched mutex_lock(struct mutex * lock); ARGUMENTS
lock the mutex to be acquired DESCRIPTION
Lock the mutex exclusively for this task. If the mutex is not available right now, it will sleep until it can get it. The mutex must later on be released by the same task that acquired it. Recursive locking is not allowed. The task may not exit without first unlocking the mutex. Also, kernel memory where the mutex resides mutex must not be freed with the mutex still locked. The mutex must first be initialized (or statically defined) before it can be locked. memset-ing the mutex to 0 is not allowed. ( The CONFIG_DEBUG_MUTEXES .config option turns on debugging checks that will enforce the restrictions and will also do deadlock debugging. ) This function is similar to (but not equivalent to) down. AUTHOR
Rusty Russell <rusty@rustcorp.com.au> Author. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 MUTEX_LOCK(9)

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pthread_mutex_lock(3T)													    pthread_mutex_lock(3T)

NAME
pthread_mutex_lock(), pthread_mutex_trylock() - lock or attempt to lock a mutex SYNOPSIS
PARAMETERS
mutex Pointer to the mutex to be locked. DESCRIPTION
The mutex object mutex is locked by calling the function. How the calling thread acquires the mutex is dependent upon the type attribute for the mutex. This operation returns with the mutex object referenced by mutex in the locked state with the calling thread as its owner. If the mutex type is deadlock detection is not provided. Attempting to relock the mutex causes deadlock. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, undefined behavior results. If the mutex type is the mutex maintains the concept of an owner. If a thread attempts to relock a mutex that it has already locked, an error shall be returned. If a thread attempts to unlock a mutex that it has not locked or a mutex that is unlocked, an error shall be returned. If the mutex type is then the mutex maintains the concept of an owner and a lock count. When a thread successfully acquires a mutex for the first time, the count field shall be set to one. Every time a thread relocks this mutex, the count field shall be incremented by one. Each time the thread unlocks the mutex, the count field shall be decremented by one. When the count field reaches zero, the mutex shall become available for other threads to acquire. If a thread attempts to unlock a mutex that it has not locked, an error shall be returned. If the mutex type is deadlock detection is not provided. Attempting to relock the mutex causes deadlock. A thread can unlock a mutex that it has not locked. Attempting to unlock an unlocked mutex results in undefined behavior. If the mutex type is attempting to recursively lock the mutex results in undefined behavior. Attempting to unlock the mutex if it was not locked by the calling thread results in undefined behavior. Attempting to unlocked the mutex if it is not locked results in undefined behavior. The function is identical to the function except that if the mutex object referenced by mutex cannot be acquired after one attempt, the call returns immediately with an error. If a signal is delivered to a thread waiting for a mutex, upon return from the signal handler, the thread shall resume waiting for the mutex as if it was not interrupted. 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 and functions return the corresponding error number: [EINVAL] mutex is a mutex and the caller's priority is higher than mutex's priority ceiling. If any of the following occur, the function returns the corresponding error number: [EBUSY] mutex is currently locked by another thread. If any of the following occur, the and functions return the corresponding error number: [EAGAIN] mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded. This error is not detected on HP-UX. [EINVAL] mutex is not an initialized mutex. [EFAULT] mutex parameter points to an illegal address. If any of the following occur, the function returns the corresponding error number: [EDEADLK] The current thread already owns the mutex. This error will be detected only for mutexes on HP-UX. WARNINGS
A recursive mutex can be locked more than once by the same thread without causing that thread to deadlock. Undefined behavior may result if the owner of a recursive mutex tries to lock the mutex too many times. AUTHOR
and was derived from the IEEE POSIX P1003.1c standard and X/Open SEE ALSO
pthread_mutex_init(3T), pthread_mutex_destroy(3T), pthread_mutex_unlock(3T). STANDARDS CONFORMANCE
Pthread Library pthread_mutex_lock(3T)
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