44 lines
1.5 KiB
C++
44 lines
1.5 KiB
C++
/*******************************************************************************
|
|
|
|
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;
|
|
}
|