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Add pthread_mutex_trylock(3).

This commit is contained in:
Jonas 'Sortie' Termansen 2013-08-31 14:55:16 +02:00
parent 23d05cba97
commit 65ed6a208c
3 changed files with 45 additions and 1 deletions
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1
libpthread/Makefile
View File

@ -14,6 +14,7 @@ OBJS=\
pthread_equal.o \
pthread_initialize.o \
pthread_mutex_lock.o \
pthread_mutex_trylock.o \
pthread_mutex_unlock.o \
pthread_self.o \

2
libpthread/include/pthread.h
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@ -210,7 +210,7 @@ int pthread_equal(pthread_t, pthread_t);
int pthread_mutex_lock(pthread_mutex_t*);
/* TODO: pthread_mutex_setprioceiling */
/* TODO: pthread_mutex_timedlock */
/* TODO: pthread_mutex_trylock */
int pthread_mutex_trylock(pthread_mutex_t*);
int pthread_mutex_unlock(pthread_mutex_t*);
/* TODO: pthread_mutexattr_destroy */
/* TODO: pthread_mutexattr_getprioceiling */

43
libpthread/pthread_mutex_trylock.c++ Normal file
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@ -0,0 +1,43 @@
/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
This file is part of Sortix libpthread.
Sortix libpthread is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
Sortix libpthread is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with Sortix libpthread. If not, see <http://www.gnu.org/licenses/>.
pthread_mutex_trylock.c++
Attempts to lock a mutex.
*******************************************************************************/
#include <errno.h>
#include <pthread.h>
static const unsigned long UNLOCKED_VALUE = 0;
static const unsigned long LOCKED_VALUE = 1;
extern "C" int pthread_mutex_trylock(pthread_mutex_t* mutex)
{
if ( !__sync_bool_compare_and_swap(&mutex->lock, UNLOCKED_VALUE, LOCKED_VALUE) )
{
if ( mutex->type == PTHREAD_MUTEX_RECURSIVE &&
(pthread_t) mutex->owner == pthread_self() )
return mutex->recursion++, 0;
return errno = EBUSY;
}
mutex->owner = (unsigned long) pthread_self();
mutex->recursion = 0;
return 0;
}