freebsd-dev/lib/libstdthreads/call_once.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <pthread.h>

#include "threads.h"

void
call_once(once_flag *flag, void (*func)(void))
{

	(void)pthread_once((pthread_once_t *)flag, func);
}

_Static_assert(sizeof(once_flag) == sizeof(pthread_once_t),
    "once_flag must be of the same size as pthread_once_t");
Add libstdthreads. This library implements the C11 threads interface on top of the pthreads library. As discussed on the lists, the preferred way to implement this, is as a separate library. It is unlikely that these functions will be used a lot in the future. It would have been easier if the C11 working group standardized (a subset of) pthreads and clock_nanosleep(). Having it as a separate library allows the embedded people to omit it from their system. Discussed on: arch@, threads@ 2011-12-26 21:51:53 +00:00			`/*-`
lib: further adoption of SPDX licensing ID tags. Mainly focus on files that use BSD 2-Clause license, however the tool I was using mis-identified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. 2017-11-26 02:00:33 +00:00			`* SPDX-License-Identifier: BSD-2-Clause-FreeBSD`
			`*`
Add libstdthreads. This library implements the C11 threads interface on top of the pthreads library. As discussed on the lists, the preferred way to implement this, is as a separate library. It is unlikely that these functions will be used a lot in the future. It would have been easier if the C11 working group standardized (a subset of) pthreads and clock_nanosleep(). Having it as a separate library allows the embedded people to omit it from their system. Discussed on: arch@, threads@ 2011-12-26 21:51:53 +00:00			`* Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>`
			`* All rights reserved.`
			`*`
			`* Redistribution and use in source and binary forms, with or without`
			`* modification, are permitted provided that the following conditions`
			`* are met:`
			`* 1. Redistributions of source code must retain the above copyright`
			`* notice, this list of conditions and the following disclaimer.`
			`* 2. Redistributions in binary form must reproduce the above copyright`
			`* notice, this list of conditions and the following disclaimer in the`
			`* documentation and/or other materials provided with the distribution.`
			`*`
			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
			`* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE`
			`* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`* SUCH DAMAGE.`
			`*`
			`* $FreeBSD$`
			`*/`

			`#include <sys/cdefs.h>`
			`__FBSDID("$FreeBSD$");`

			`#include <pthread.h>`

			`#include "threads.h"`

			`void`
			`call_once(once_flag flag, void (func)(void))`
			`{`

			`(void)pthread_once((pthread_once_t *)flag, func);`
			`}`

			`_Static_assert(sizeof(once_flag) == sizeof(pthread_once_t),`
			`"once_flag must be of the same size as pthread_once_t");`