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Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
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$FreeBSD: src/lib/libpthread/man/pthread_mutexattr.3,v 1.8 2002/09/16 19:29:29 mini Exp $
.Dd January 30, 2003 .Dt PTHREAD_MUTEXATTR 3 .Os .Sh NAME .Nm pthread_mutexattr_destroy , .Nm pthread_mutexattr_getprioceiling , .Nm pthread_mutexattr_getprotocol , .Nm pthread_mutexattr_gettype , .Nm pthread_mutexattr_init , .Nm pthread_mutexattr_setprioceiling , .Nm pthread_mutexattr_setprotocol , .Nm pthread_mutexattr_settype .Nd mutex attribute operations .Sh SYNOPSIS .Fd #include <pthread.h> .Ft int .Fo pthread_mutexattr_destroy .Fa "pthread_mutexattr_t *attr" .Fc .Ft int .Fo pthread_mutexattr_getprioceiling .Fa "const pthread_mutexattr_t *restrict attr" .Fa "int *restrict prioceiling" .Fc To match the SUS, this should be:
.Ft int
.Fo pthread_mutexattr_getprioceiling
.Fa "pthread_mutexattr_t *restrict attr"
.Fa "int *restrict prioceiling"
.Fc
.Ft int .Fo pthread_mutexattr_getprotocol .Fa "const pthread_mutexattr_t *restrict attr" .Fa "int *restrict protocol" .Fc To match the SUS, this should be:
.Ft int
.Fo pthread_mutexattr_getprotocol
.Fa "pthread_mutexattr_t *restrict attr"
.Fa "int *restrict protocol"
.Fc
.Ft int .Fo pthread_mutexattr_gettype .Fa "const pthread_mutexattr_t *restrict attr" .Fa "int *restrict type" .Fc To match the SUS, this should be:
.Ft int
.Fo pthread_mutexattr_gettype
.Fa "pthread_mutexattr_t *restrict attr"
.Fa "int *restrict type"
.Fc
.Ft int .Fo pthread_mutexattr_init .Fa "pthread_mutexattr_t *attr" .Fc .Ft int .Fo pthread_mutexattr_setprioceiling .Fa "pthread_mutexattr_t *attr" .Fa "int prioceiling" .Fc .Ft int .Fo pthread_mutexattr_setprotocol .Fa "pthread_mutexattr_t *attr" .Fa "int protocol" .Fc .Ft int .Fo pthread_mutexattr_settype .Fa "pthread_mutexattr_t *attr" .Fa "int type" .Fc .Sh DESCRIPTION Mutex attributes are used to specify parameters to .Fn pthread_mutex_init . One attribute object can be used in multiple calls to .Fn pthread_mutex_init , with or without modifications between calls.
p The .Fn pthread_mutexattr_init function initializes .Fa attr with all of the default mutex attributes.
p The .Fn pthread_mutexattr_destroy function destroys .Fa attr .
p The .Fn pthread_mutexattr_settype function sets the mutex type value of the attribute. Valid mutex types are: .Dv PTHREAD_MUTEX_NORMAL , .Dv PTHREAD_MUTEX_ERRORCHECK , .Dv PTHREAD_MUTEX_RECURSIVE , and .Dv PTHREAD_MUTEX_DEFAULT . The default mutex type for .Fn pthread_mutexattr_init is .Dv PTHREAD_MUTEX_DEFAULT .
p .Dv PTHREAD_MUTEX_NORMAL mutexes do not check for usage errors. .Dv PTHREAD_MUTEX_NORMAL mutexes will deadlock if reentered, and result in undefined behavior if a locked mutex is unlocked by another thread. Attempts to unlock an already unlocked .Dv PTHREAD_MUTEX_NORMAL mutex will result in undefined behavior.
p .Dv PTHREAD_MUTEX_ERRORCHECK mutexes do check for usage errors. If an attempt is made to relock a .Dv PTHREAD_MUTEX_ERRORCHECK mutex without first dropping the lock, an error will be returned. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_ERRORCHECK mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_ERRORCHECK thread that is unlocked, an error will be returned.
p .Dv PTHREAD_MUTEX_RECURSIVE mutexes allow recursive locking. An attempt to relock a .Dv PTHREAD_MUTEX_RECURSIVE mutex that is already locked by the same thread succeeds. An equivalent number of .Xr pthread_mutex_unlock 3 calls are needed before the mutex will wake another thread waiting on this lock. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_RECURSIVE mutex that is locked by another thread, an error will be returned. If a thread attemps to unlock a .Dv PTHREAD_MUTEX_RECURSIVE thread that is unlocked, an error will be returned.
p .Dv PTHREAD_MUTEX_DEFAULT mutexes result in undefined behavior if reentered. Unlocking a .Dv PTHREAD_MUTEX_DEFAULT mutex locked by another thread will result in undefined behavior. Attempts to unlock an already unlocked .Dv PTHREAD_MUTEX_DEFAULT mutex will result in undefined behavior.
p .Fn pthread_mutexattr_gettype functions copy the type value of the attribute to the location pointed to by the second parameter.
p The .Fn pthread_mutexattr_set* functions set the attribute that corresponds to each function name.
p The .Fn pthread_mutexattr_get* functions copy the value of the attribute that corresponds to each function name to the location pointed to by the second function parameter. .Sh RETURN VALUES If successful, these functions return 0. Otherwise, an error number is returned to indicate the error. .Sh ERRORS .Fn pthread_mutexattr_init will fail if: l -tag -width Er t Bq Er ENOMEM Out of memory. .El
p .Fn pthread_mutexattr_destroy will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr . .El
p .Fn pthread_mutexattr_setprioceiling will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr , or invalid value for .Fa prioceiling . .El
p .Fn pthread_mutexattr_getprioceiling will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr . .El
p .Fn pthread_mutexattr_setprotocol will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr , or invalid value for .Fa protocol . .El
p .Fn pthread_mutexattr_getprotocol will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr . .El
p .Fn pthread_mutexattr_settype will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr , or invalid value for .Fa type . .El
p .Fn pthread_mutexattr_gettype will fail if: l -tag -width Er t Bq Er EINVAL Invalid value for .Fa attr . .El .Sh SEE ALSO .Xr pthread_mutex_init 3 .Sh STANDARDS .Fn pthread_mutexattr_init and .Fn pthread_mutexattr_destroy conform to .St -p1003.1-96
p .Fn pthread_mutexattr_setprioceiling , .Fn pthread_mutexattr_getprioceiling , .Fn pthread_mutexattr_setprotocol , .Fn pthread_mutexattr_getprotocol , .Fn pthread_mutexattr_settype , and .Fn pthread_mutexattr_gettype conform to .St -susv2