[apple/libc.git] / fbsdcompat / reentrant.h

/*-
 * Copyright (c) 1997,98 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by J.T. Conklin.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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: src/lib/libc/include/reentrant.h,v 1.3 2004/02/25 21:03:45 green Exp $
 */

/*
 * Requirements:
 * 
 * 1. The thread safe mechanism should be lightweight so the library can
 *    be used by non-threaded applications without unreasonable overhead.
 * 
 * 2. There should be no dependency on a thread engine for non-threaded
 *    applications.
 * 
 * 3. There should be no dependency on any particular thread engine.
 * 
 * 4. The library should be able to be compiled without support for thread
 *    safety.
 * 
 * 
 * Rationale:
 * 
 * One approach for thread safety is to provide discrete versions of the
 * library: one thread safe, the other not.  The disadvantage of this is
 * that libc is rather large, and two copies of a library which are 99%+
 * identical is not an efficent use of resources.
 * 
 * Another approach is to provide a single thread safe library.  However,
 * it should not add significant run time or code size overhead to non-
 * threaded applications.
 * 
 * Since the NetBSD C library is used in other projects, it should be
 * easy to replace the mutual exclusion primitives with ones provided by
 * another system.  Similarly, it should also be easy to remove all
 * support for thread safety completely if the target environment does
 * not support threads.
 * 
 * 
 * Implementation Details:
 * 
 * The mutex primitives used by the library (mutex_t, mutex_lock, etc.)
 * are macros which expand to the cooresponding primitives provided by
 * the thread engine or to nothing.  The latter is used so that code is
 * not unreasonably cluttered with #ifdefs when all thread safe support
 * is removed.
 * 
 * The mutex macros can be directly mapped to the mutex primitives from
 * pthreads, however it should be reasonably easy to wrap another mutex
 * implementation so it presents a similar interface.
 * 
 * Stub implementations of the mutex functions are provided with *weak*
 * linkage.  These functions simply return success.  When linked with a
 * thread library (i.e. -lpthread), the functions will override the
 * stubs.
 */

#include <pthread.h>
#include "libc_private.h"

#define mutex_t			pthread_mutex_t
#define cond_t			pthread_cond_t
#define rwlock_t		pthread_rwlock_t
#define once_t			pthread_once_t

#define thread_key_t		pthread_key_t
#define MUTEX_INITIALIZER	PTHREAD_MUTEX_INITIALIZER
#define RWLOCK_INITIALIZER	PTHREAD_RWLOCK_INITIALIZER
#define ONCE_INITIALIZER	PTHREAD_ONCE_INIT

#define mutex_init(m, a)	_pthread_mutex_init(m, a)
#define mutex_lock(m)		if (__isthreaded) \
				_pthread_mutex_lock(m)
#define mutex_unlock(m)		if (__isthreaded) \
				_pthread_mutex_unlock(m)
#define mutex_trylock(m)	(__isthreaded ? 0 : _pthread_mutex_trylock(m))

#define cond_init(c, a, p)	_pthread_cond_init(c, a)
#define cond_signal(m)		if (__isthreaded) \
				_pthread_cond_signal(m)
#define cond_broadcast(m)	if (__isthreaded) \
				_pthread_cond_broadcast(m)
#define cond_wait(c, m)		if (__isthreaded) \
				_pthread_cond_wait(c, m)

#define rwlock_init(l, a)	_pthread_rwlock_init(l, a)
#define rwlock_rdlock(l)	if (__isthreaded) \
				_pthread_rwlock_rdlock(l)
#define rwlock_wrlock(l)	if (__isthreaded) \
				_pthread_rwlock_wrlock(l)
#define rwlock_unlock(l)	if (__isthreaded) \
				_pthread_rwlock_unlock(l)

#define thr_keycreate(k, d)	_pthread_key_create(k, d)
#define thr_setspecific(k, p)	_pthread_setspecific(k, p)
#define thr_getspecific(k)	_pthread_getspecific(k)
#define thr_sigsetmask(f, n, o)	_pthread_sigmask(f, n, o)

#define thr_once(o, i)		_pthread_once(o, i)
#define thr_self()		_pthread_self()
#define thr_exit(x)		_pthread_exit(x)
#define thr_main()		_pthread_main_np()
Commit	Line	Data
1f2f436a A	1	/*-
	2	* Copyright (c) 1997,98 The NetBSD Foundation, Inc.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to The NetBSD Foundation
	6	* by J.T. Conklin.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the NetBSD
	19	* Foundation, Inc. and its contributors.
	20	* 4. Neither the name of The NetBSD Foundation nor the names of its
	21	* contributors may be used to endorse or promote products derived
	22	* from this software without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
	25	* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	26	* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	27	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
	28	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	29	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	30	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	31	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	32	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	33	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	34	* POSSIBILITY OF SUCH DAMAGE.
	35	*
	36	* $FreeBSD: src/lib/libc/include/reentrant.h,v 1.3 2004/02/25 21:03:45 green Exp $
	37	*/
	38
	39	/*
	40	* Requirements:
	41	*
	42	* 1. The thread safe mechanism should be lightweight so the library can
	43	* be used by non-threaded applications without unreasonable overhead.
	44	*
	45	* 2. There should be no dependency on a thread engine for non-threaded
	46	* applications.
	47	*
	48	* 3. There should be no dependency on any particular thread engine.
	49	*
	50	* 4. The library should be able to be compiled without support for thread
	51	* safety.
	52	*
	53	*
	54	* Rationale:
	55	*
	56	* One approach for thread safety is to provide discrete versions of the
	57	* library: one thread safe, the other not. The disadvantage of this is
	58	* that libc is rather large, and two copies of a library which are 99%+
	59	* identical is not an efficent use of resources.
	60	*
	61	* Another approach is to provide a single thread safe library. However,
	62	* it should not add significant run time or code size overhead to non-
	63	* threaded applications.
	64	*
65	* Since the NetBSD C library is used in other projects, it should be
66	* easy to replace the mutual exclusion primitives with ones provided by
67	* another system. Similarly, it should also be easy to remove all
68	* support for thread safety completely if the target environment does
69	* not support threads.
70	*
71	*
72	* Implementation Details:
73	*
74	* The mutex primitives used by the library (mutex_t, mutex_lock, etc.)
75	* are macros which expand to the cooresponding primitives provided by
76	* the thread engine or to nothing. The latter is used so that code is
77	* not unreasonably cluttered with #ifdefs when all thread safe support
78	* is removed.
79	*
80	* The mutex macros can be directly mapped to the mutex primitives from
81	* pthreads, however it should be reasonably easy to wrap another mutex
82	* implementation so it presents a similar interface.
83	*
84	* Stub implementations of the mutex functions are provided with weak
85	* linkage. These functions simply return success. When linked with a
86	* thread library (i.e. -lpthread), the functions will override the
87	* stubs.
88	*/
89
90	#include <pthread.h>
91	#include "libc_private.h"
92
93	#define mutex_t pthread_mutex_t
94	#define cond_t pthread_cond_t
95	#define rwlock_t pthread_rwlock_t
96	#define once_t pthread_once_t
97
98	#define thread_key_t pthread_key_t
99	#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
100	#define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER
101	#define ONCE_INITIALIZER PTHREAD_ONCE_INIT
102
103	#define mutex_init(m, a) _pthread_mutex_init(m, a)
104	#define mutex_lock(m) if (__isthreaded) \
105	_pthread_mutex_lock(m)
106	#define mutex_unlock(m) if (__isthreaded) \
107	_pthread_mutex_unlock(m)
108	#define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m))
109
110	#define cond_init(c, a, p) _pthread_cond_init(c, a)
111	#define cond_signal(m) if (__isthreaded) \
112	_pthread_cond_signal(m)
113	#define cond_broadcast(m) if (__isthreaded) \
114	_pthread_cond_broadcast(m)
115	#define cond_wait(c, m) if (__isthreaded) \
116	_pthread_cond_wait(c, m)
117
118	#define rwlock_init(l, a) _pthread_rwlock_init(l, a)
119	#define rwlock_rdlock(l) if (__isthreaded) \
120	_pthread_rwlock_rdlock(l)
121	#define rwlock_wrlock(l) if (__isthreaded) \
122	_pthread_rwlock_wrlock(l)
123	#define rwlock_unlock(l) if (__isthreaded) \
124	_pthread_rwlock_unlock(l)
125
126	#define thr_keycreate(k, d) _pthread_key_create(k, d)
127	#define thr_setspecific(k, p) _pthread_setspecific(k, p)
128	#define thr_getspecific(k) _pthread_getspecific(k)
129	#define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o)
130
131	#define thr_once(o, i) _pthread_once(o, i)
132	#define thr_self() _pthread_self()
133	#define thr_exit(x) _pthread_exit(x)
134	#define thr_main() _pthread_main_np()