diff options
Diffstat (limited to 'nptl/pthread_rwlock_tryrdlock.c')
| -rw-r--r-- | nptl/pthread_rwlock_tryrdlock.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/nptl/pthread_rwlock_tryrdlock.c b/nptl/pthread_rwlock_tryrdlock.c new file mode 100644 index 0000000000..446af05969 --- /dev/null +++ b/nptl/pthread_rwlock_tryrdlock.c @@ -0,0 +1,50 @@ +/* Copyright (C) 2002 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + + The GNU C 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 2.1 of the License, or (at your option) any later version. + + The GNU C 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 the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include "pthreadP.h" +#include <lowlevellock.h> + + +int +__pthread_rwlock_tryrdlock (rwlock) + pthread_rwlock_t *rwlock; +{ + int result = EBUSY; + + lll_mutex_lock (rwlock->__data.__lock); + + if (rwlock->__data.__writer == 0 + && (rwlock->__data.__nr_writers_queued == 0 + || rwlock->__data.__flags == 0)) + { + if (__builtin_expect (++rwlock->__data.__nr_readers == 0, 0)) + { + --rwlock->__data.__nr_readers; + result = EAGAIN; + } + else + result = 0; + } + + lll_mutex_unlock (rwlock->__data.__lock); + + return result; +} +strong_alias (__pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock) |