From 4878d30d853a947ea22de2ac8aa2dca6c1035821 Mon Sep 17 00:00:00 2001 From: "Neal H. Walfield" Date: Thu, 12 May 2005 11:50:42 +0000 Subject: libpthread/ 2005-05-12 Neal H. Walfield * Makefile (SRCS): Add sem-close.c sem-destroy.c sem-getvalue.c sem-init.c sem-open.c sem-post.c sem-timedwait.c sem-trywait.c sem-unlink.c and sem-wait.c. (sysdeps_headers): Add semaphore.h bits/semaphore.h. * include/semaphore.h: New file. * sysdeps/generic/sem-close.c: New file. * sysdeps/generic/sem-destroy.c: New file. * sysdeps/generic/sem-getvalue.c: New file. * sysdeps/generic/sem-init.c: New file. * sysdeps/generic/sem-open.c: New file. * sysdeps/generic/sem-post.c: New file. * sysdeps/generic/sem-timedwait.c: New file. * sysdeps/generic/sem-trywait.c: New file. * sysdeps/generic/sem-unlink.c: New file. * sysdeps/generic/sem-wait.c: New file. * sysdeps/generic/bits/semaphore.h: New file. --- sysdeps/generic/sem-trywait.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 sysdeps/generic/sem-trywait.c (limited to 'sysdeps/generic/sem-trywait.c') diff --git a/sysdeps/generic/sem-trywait.c b/sysdeps/generic/sem-trywait.c new file mode 100644 index 00000000..e47d5595 --- /dev/null +++ b/sysdeps/generic/sem-trywait.c @@ -0,0 +1,42 @@ +/* Lock a semaphore if it does not require blocking. Generic version. + Copyright (C) 2005 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include +#include + +#include + +int +__sem_trywait (sem_t *sem) +{ + __pthread_spin_lock (&sem->__lock); + if (sem->__value > 0) + /* Successful down. */ + { + sem->__value --; + __pthread_spin_unlock (&sem->__lock); + return 0; + } + __pthread_spin_unlock (&sem->__lock); + + errno = EAGAIN; + return -1; +} + +weak_alias (__sem_trywait, sem_trywait); -- cgit v1.2.3