glibc/sysdeps/htl/sem-getvalue.c
Samuel Thibault 8ba6ad703c hurd: Add __pthread_spin_wait and use it
900778283a ("htl: make pthread_spin_lock really spin") made
pthread_spin_lock really spin and not block, but the current users of
__pthread_spin_lock were assuming that it blocks, i.e. they use it as a
lightweight mutex fitting in just one int.

__pthread_spin_wait provides that support back.
2020-02-11 00:32:44 +01:00

33 lines
1.1 KiB
C

/* Get the value of a semaphore. Generic version.
Copyright (C) 2005-2020 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 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
<https://www.gnu.org/licenses/>. */
#include <semaphore.h>
#include <pt-internal.h>
int
__sem_getvalue (sem_t *restrict sem, int *restrict value)
{
__pthread_spin_wait (&sem->__lock);
*value = sem->__value;
__pthread_spin_unlock (&sem->__lock);
return 0;
}
strong_alias (__sem_getvalue, sem_getvalue);