diff options
Diffstat (limited to 'libpthread/nptl/pthread_mutex_trylock.c')
-rw-r--r-- | libpthread/nptl/pthread_mutex_trylock.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_mutex_trylock.c b/libpthread/nptl/pthread_mutex_trylock.c new file mode 100644 index 000000000..7008af3d9 --- /dev/null +++ b/libpthread/nptl/pthread_mutex_trylock.c @@ -0,0 +1,77 @@ +/* Copyright (C) 2002, 2003 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_mutex_trylock (mutex) + pthread_mutex_t *mutex; +{ + pid_t id; + + switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP)) + { + /* Recursive mutex. */ + case PTHREAD_MUTEX_RECURSIVE_NP: + id = THREAD_GETMEM (THREAD_SELF, tid); + /* Check whether we already hold the mutex. */ + if (mutex->__data.__owner == id) + { + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + return 0; + } + + if (lll_mutex_trylock (mutex->__data.__lock) == 0) + { + /* Record the ownership. */ + mutex->__data.__owner = id; + mutex->__data.__count = 1; + ++mutex->__data.__nusers; + return 0; + } + break; + + case PTHREAD_MUTEX_ERRORCHECK_NP: + /* Error checking mutex. We do not check for deadlocks. */ + default: + /* Correct code cannot set any other type. */ + case PTHREAD_MUTEX_TIMED_NP: + case PTHREAD_MUTEX_ADAPTIVE_NP: + /* Normal mutex. */ + if (lll_mutex_trylock (mutex->__data.__lock) == 0) + { + /* Record the ownership. */ + mutex->__data.__owner = THREAD_GETMEM (THREAD_SELF, tid); + ++mutex->__data.__nusers; + + return 0; + } + } + + return EBUSY; +} +strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock) |