mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-08 06:10:06 +00:00
85 lines
3.1 KiB
Groff
85 lines
3.1 KiB
Groff
|
.TH PTHREAD_MUTEXATTR 3 LinuxThreads
|
||
|
|
|
||
|
|
.XREF pthread_mutexattr_destroy
|
||
|
|
.XREF pthread_mutexattr_setkind_np
|
||
|
|
.XREF pthread_mutexattr_getkind_np
|
||
|
|
|
||
|
|
.SH NAME
|
||
|
|
pthread_mutexattr_init, pthread_mutexattr_destroy, pthread_mutexattr_setkind_np, pthread_mutexattr_getkind_np \- 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_setkind_np(pthread_mutexattr_t *attr, int kind);
|
||
|
|
|
||
|
|
int pthread_mutexattr_getkind_np(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_setkind_np! sets the mutex kind attribute in |attr|
|
||
|
|
to the value specified by |kind|.
|
||
|
|
|
||
|
|
!pthread_mutexattr_getkind_np! 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_getkind_np! always return 0.
|
||
|
|
|
||
|
|
!pthread_mutexattr_setkind_np! returns 0 on success and a non-zero
|
||
|
|
error code on error.
|
||
|
|
|
||
|
|
.SH ERRORS
|
||
|
|
|
||
|
|
On error, !pthread_mutexattr_setkind_np! 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).
|