WW_MUTEX_UNLOCK(9) Mutex API reference WW_MUTEX_UNLOCK(9)NAME
ww_mutex_unlock - release the w/w mutex
SYNOPSIS
void __sched ww_mutex_unlock(struct ww_mutex * lock);
ARGUMENTS
lock
the mutex to be released
DESCRIPTION
Unlock a mutex that has been locked by this task previously with any of the ww_mutex_lock* functions (with or without an acquire context).
It is forbidden to release the locks after releasing the acquire context.
This function must not be used in interrupt context. Unlocking of a unlocked mutex is not allowed.
AUTHOR
Rusty Russell <rusty@rustcorp.com.au>
Author.
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 WW_MUTEX_UNLOCK(9)
Check Out this Related Man Page
pthread_mutex_trylock(3) Library Functions Manual pthread_mutex_trylock(3)NAME
pthread_mutex_trylock - Attempts to lock the specified mutex, without waiting if already locked.
LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so)
SYNOPSIS
#include <pthread.h>
int pthread_mutex_trylock(
pthread_mutex_t *mutex);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
PARAMETERS
Mutex to be locked.
DESCRIPTION
This routine attempts to lock the mutex specified in the mutex argument. When a thread calls this routine, an attempt is made to immedi-
ately lock the mutex. If the mutex is successfully locked, this routine returns zero (0) and the calling thread becomes the mutex's current
owner. If the specified mutex is locked when a thread calls this routine, the calling thread does not wait for the mutex to become avail-
able.
The behavior of this routine is as follows: For a normal, default, or errorcheck mutex: if the mutex is locked by any thread (including the
calling thread) when this routine is called, this routine returns [EBUSY] and the calling thread does not wait to acquire the lock. For a
normal or errorcheck mutex: if the mutex is not owned, this routine returns zero (0) and the mutex becomes locked by the calling thread.
For a recursive mutex: if the mutex is owned by the calling thread, this routine returns zero (0) and the mutex lock count is incremented.
(To unlock a recursive mutex, each call to pthread_mutex_trylock(3) must be matched by a call to pthread_mutex_unlock(3).)
Use the pthread_mutexattr_settype(3) routine to set the mutex type attribute (normal, default, recursive, or errorcheck).
RETURN VALUES
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows:
Successful completion. The mutex is already locked; therefore, it was not acquired. The value specified by mutex is not a valid mutex.
ERRORS
None
RELATED INFORMATION
Functions: pthread_mutexattr_settype(3), pthread_mutex_destroy(3), pthread_mutex_init(3), pthread_mutex_lock(3), pthread_mutex_unlock(3)
Manuals: Guide to DECthreads and Programmer's Guide
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pthread_mutex_trylock(3)
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