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/* Copyright (C) 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#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 oldval;
int newval;
/* Atomically decrement sem counter if it is > 0. */
lll_compare_and_swap ((int *) sem, oldval, newval,
"ltr %2,%1; jnp 1f; ahi %2,-1");
/* oldval != newval if the semaphore count has been decremented. */
if (oldval == newval)
{
__set_errno (EAGAIN);
return -1;
}
return 0;
}
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
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