| /* sem_trywait -- wait on a semaphore. Generic futex-using version. |
| Copyright (C) 2003-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. |
| |
| 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <sysdep.h> |
| #include <lowlevellock.h> |
| #include <internaltypes.h> |
| #include <semaphore.h> |
| |
| #include <shlib-compat.h> |
| |
| |
| int |
| __new_sem_trywait (sem_t *sem) |
| { |
| int *futex = (int *) sem; |
| int val; |
| |
| if (*futex > 0) |
| { |
| val = atomic_decrement_if_positive (futex); |
| if (val > 0) |
| return 0; |
| } |
| |
| __set_errno (EAGAIN); |
| return -1; |
| } |
| versioned_symbol (libpthread, __new_sem_trywait, sem_trywait, GLIBC_2_1); |
| #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) |
| strong_alias (__new_sem_trywait, __old_sem_trywait) |
| compat_symbol (libpthread, __old_sem_trywait, sem_trywait, GLIBC_2_0); |
| #endif |
