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/* sem_trywait -- wait on a semaphore. SPARC version.
Copyright (C) 2003, 2006, 2007 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>
int
sem_trywait (sem_t *sem)
{
struct sparc_old_sem *isem = (struct sparc_old_sem *) sem;
int val;
if (isem->value > 0)
{
if (__atomic_is_v9)
val = atomic_decrement_if_positive (&isem->value);
else
{
__sparc32_atomic_do_lock24 (&isem->lock);
val = isem->value;
if (val > 0)
isem->value = val - 1;
__sparc32_atomic_do_unlock24 (&isem->lock);
}
if (val > 0)
return 0;
}
__set_errno (EAGAIN);
return -1;
}
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