glibc/support/support_mutex_pi_monotonic.c

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/* Returns whether Priority Inheritance support CLOCK_MONOTONIC.
Copyright (C) 2021-2022 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 <support/xthread.h>
#include <sys/syscall.h>
#include <unistd.h>
bool
support_mutex_pi_monotonic (void)
{
#ifdef __linux__
# ifndef __NR_futex
# define __NR_futex __NR_futex_time64
# endif
int r = syscall (__NR_futex, &(unsigned int){0}, 13 /* FUTEX_LOCK_PI2 */,
0, NULL);
return r == 0;
#else
return false;
#endif
}