diff options
Diffstat (limited to 'pthreads/pthread_spin_trylock.c')
-rw-r--r-- | pthreads/pthread_spin_trylock.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/pthreads/pthread_spin_trylock.c b/pthreads/pthread_spin_trylock.c new file mode 100644 index 000000000..c601a191f --- /dev/null +++ b/pthreads/pthread_spin_trylock.c @@ -0,0 +1,80 @@ +/* + * pthread_spin_trylock.c + * + * Description: + * This translation unit implements spin lock primitives. + * + * -------------------------------------------------------------------------- + * + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright(C) 1998 John E. Bossom + * Copyright(C) 1999,2005 Pthreads-win32 contributors + * + * Contact Email: rpj@callisto.canberra.edu.au + * + * The current list of contributors is contained + * in the file CONTRIBUTORS included with the source + * code distribution. The list can also be seen at the + * following World Wide Web location: + * http://sources.redhat.com/pthreads-win32/contributors.html + * + * This library 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 2 of the License, or (at your option) any later version. + * + * This library 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 this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include "pthread.h" +#include "implement.h" + + +int +pthread_spin_trylock (pthread_spinlock_t * lock) +{ + register pthread_spinlock_t s; + + if (NULL == lock || NULL == *lock) + { + return (EINVAL); + } + + if (*lock == PTHREAD_SPINLOCK_INITIALIZER) + { + int result; + + if ((result = ptw32_spinlock_check_need_init (lock)) != 0) + { + return (result); + } + } + + s = *lock; + + switch ((long) + PTW32_INTERLOCKED_COMPARE_EXCHANGE ((PTW32_INTERLOCKED_LPLONG) & + (s->interlock), + (PTW32_INTERLOCKED_LONG) + PTW32_SPIN_LOCKED, + (PTW32_INTERLOCKED_LONG) + PTW32_SPIN_UNLOCKED)) + { + case PTW32_SPIN_UNLOCKED: + return 0; + case PTW32_SPIN_LOCKED: + return EBUSY; + case PTW32_SPIN_USE_MUTEX: + return pthread_mutex_trylock (&(s->u.mutex)); + } + + return EINVAL; +} |