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Diffstat (limited to 'linuxthreads/man/pthread_mutexattr_init.man')
| -rw-r--r-- | linuxthreads/man/pthread_mutexattr_init.man | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/linuxthreads/man/pthread_mutexattr_init.man b/linuxthreads/man/pthread_mutexattr_init.man new file mode 100644 index 0000000000..b838948904 --- /dev/null +++ b/linuxthreads/man/pthread_mutexattr_init.man @@ -0,0 +1,84 @@ +.TH PTHREAD_MUTEXATTR 3 LinuxThreads + +.XREF pthread_mutexattr_destroy +.XREF pthread_mutexattr_settype +.XREF pthread_mutexattr_gettype + +.SH NAME +pthread_mutexattr_init, pthread_mutexattr_destroy, pthread_mutexattr_settype, pthread_mutexattr_gettype \- mutex creation attributes + +.SH SYNOPSIS +#include <pthread.h> + +int pthread_mutexattr_init(pthread_mutexattr_t *attr); + +int pthread_mutexattr_destroy(pthread_mutexattr_t *attr); + +int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int kind); + +int pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *kind); + +.SH DESCRIPTION + +Mutex attributes can be specified at mutex creation time, by passing a +mutex attribute object as second argument to !pthread_mutex_init!(3). +Passing !NULL! is equivalent to passing a mutex attribute object with +all attributes set to their default values. + +!pthread_mutexattr_init! initializes the mutex attribute object |attr| +and fills it with default values for the attributes. + +!pthread_mutexattr_destroy! destroys a mutex attribute object, which +must not be reused until it is reinitialized. !pthread_mutexattr_destroy! +does nothing in the LinuxThreads implementation. + +LinuxThreads supports only one mutex attribute: the mutex kind, which +is either !PTHREAD_MUTEX_FAST_NP! for ``fast'' mutexes, +!PTHREAD_MUTEX_RECURSIVE_NP! for ``recursive'' mutexes, +or !PTHREAD_MUTEX_ERRORCHECK_NP! for ``error checking'' mutexes. +As the !NP! suffix indicates, this is a non-portable extension to the +POSIX standard and should not be employed in portable programs. + +The mutex kind determines what happens if a thread attempts to lock a +mutex it already owns with !pthread_mutex_lock!(3). If the mutex is of +the ``fast'' kind, !pthread_mutex_lock!(3) simply suspends the calling +thread forever. If the mutex is of the ``error checking'' kind, +!pthread_mutex_lock!(3) returns immediately with the error code +!EDEADLK!. If the mutex is of the ``recursive'' kind, the call to +!pthread_mutex_lock!(3) returns immediately with a success return +code. The number of times the thread owning the mutex has locked it is +recorded in the mutex. The owning thread must call +!pthread_mutex_unlock!(3) the same number of times before the mutex +returns to the unlocked state. + +The default mutex kind is ``fast'', that is, !PTHREAD_MUTEX_FAST_NP!. + +!pthread_mutexattr_settype! sets the mutex kind attribute in |attr| +to the value specified by |kind|. + +!pthread_mutexattr_gettype! retrieves the current value of the +mutex kind attribute in |attr| and stores it in the location pointed +to by |kind|. + +.SH "RETURN VALUE" +!pthread_mutexattr_init!, !pthread_mutexattr_destroy! and +!pthread_mutexattr_gettype! always return 0. + +!pthread_mutexattr_settype! returns 0 on success and a non-zero +error code on error. + +.SH ERRORS + +On error, !pthread_mutexattr_settype! returns the following error code: +.TP +!EINVAL! +|kind| is neither !PTHREAD_MUTEX_FAST_NP! nor !PTHREAD_MUTEX_RECURSIVE_NP! +nor !PTHREAD_MUTEX_ERRORCHECK_NP! + +.SH AUTHOR +Xavier Leroy <Xavier.Leroy@inria.fr> + +.SH "SEE ALSO" +!pthread_mutex_init!(3), +!pthread_mutex_lock!(3), +!pthread_mutex_unlock!(3). |