299 lines
8.6 KiB
C++
299 lines
8.6 KiB
C++
/* Basic platform-independent macro definitions for mutexes and
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thread-specific data.
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Copyright (C) 1996, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* $Id$
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One out of _LIBC, USE_PTHREADS, USE_THR or USE_SPROC should be
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defined, otherwise the token NO_THREADS and dummy implementations
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of the macros will be defined. */
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#ifndef _THREAD_M_H
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#define _THREAD_M_H
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#undef thread_atfork_static
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#if defined(_LIBC) /* The GNU C library, a special case of Posix threads */
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#include <bits/libc-lock.h>
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#ifdef PTHREAD_MUTEX_INITIALIZER
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typedef pthread_t thread_id;
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/* mutex */
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typedef pthread_mutex_t mutex_t;
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#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
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/* Even if not linking with libpthread, ensure usability of mutex as
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an `in use' flag, see also the NO_THREADS case below. Assume
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pthread_mutex_t is at least one int wide. */
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#define mutex_init(m) \
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(__pthread_mutex_init != NULL \
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? __pthread_mutex_init (m, NULL) : (*(int *)(m) = 0))
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#define mutex_lock(m) \
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(__pthread_mutex_lock != NULL \
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? __pthread_mutex_lock (m) : ((*(int *)(m) = 1), 0))
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#define mutex_trylock(m) \
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(__pthread_mutex_trylock != NULL \
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? __pthread_mutex_trylock (m) : (*(int *)(m) ? 1 : ((*(int *)(m) = 1), 0)))
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#define mutex_unlock(m) \
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(__pthread_mutex_unlock != NULL \
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? __pthread_mutex_unlock (m) : (*(int*)(m) = 0))
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#define thread_atfork(prepare, parent, child) \
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(__pthread_atfork != NULL ? __pthread_atfork(prepare, parent, child) : 0)
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#elif defined(MUTEX_INITIALIZER)
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/* Assume hurd, with cthreads */
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/* Cthreads `mutex_t' is a pointer to a mutex, and malloc wants just the
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mutex itself. */
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#undef mutex_t
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#define mutex_t struct mutex
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#undef mutex_init
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#define mutex_init(m) (__mutex_init(m), 0)
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#undef mutex_lock
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#define mutex_lock(m) (__mutex_lock(m), 0)
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#undef mutex_unlock
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#define mutex_unlock(m) (__mutex_unlock(m), 0)
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#define mutex_trylock(m) (!__mutex_trylock(m))
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#define thread_atfork(prepare, parent, child) do {} while(0)
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#define thread_atfork_static(prepare, parent, child) \
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text_set_element(_hurd_fork_prepare_hook, prepare); \
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text_set_element(_hurd_fork_parent_hook, parent); \
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text_set_element(_hurd_fork_child_hook, child);
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/* No we're *not* using pthreads. */
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#define __pthread_initialize ((void (*)(void))0)
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#else
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#define NO_THREADS
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#endif /* MUTEX_INITIALIZER && PTHREAD_MUTEX_INITIALIZER */
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#ifndef NO_THREADS
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/* thread specific data for glibc */
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#include <bits/libc-tsd.h>
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typedef int tsd_key_t[1]; /* no key data structure, libc magic does it */
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__libc_tsd_define (, MALLOC) /* declaration/common definition */
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#define tsd_key_create(key, destr) ((void) (key))
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#define tsd_setspecific(key, data) __libc_tsd_set (MALLOC, (data))
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#define tsd_getspecific(key, vptr) ((vptr) = __libc_tsd_get (MALLOC))
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#endif
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#elif defined(USE_PTHREADS) /* Posix threads */
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#include <pthread.h>
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typedef pthread_t thread_id;
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/* mutex */
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#if (defined __i386__ || defined __x86_64__) && defined __GNUC__ && \
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!defined USE_NO_SPINLOCKS
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#include <time.h>
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/* Use fast inline spinlocks. */
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typedef struct {
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volatile unsigned int lock;
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int pad0_;
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} mutex_t;
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#define MUTEX_INITIALIZER { 0 }
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#define mutex_init(m) ((m)->lock = 0)
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static inline int mutex_lock(mutex_t *m) {
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int cnt = 0, r;
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struct timespec tm;
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for(;;) {
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__asm__ __volatile__
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("xchgl %0, %1"
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: "=r"(r), "=m"(m->lock)
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: "0"(1), "m"(m->lock)
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: "memory");
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if(!r)
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return 0;
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if(cnt < 50) {
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sched_yield();
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cnt++;
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} else {
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tm.tv_sec = 0;
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tm.tv_nsec = 2000001;
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nanosleep(&tm, NULL);
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cnt = 0;
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}
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}
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}
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static inline int mutex_trylock(mutex_t *m) {
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int r;
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__asm__ __volatile__
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("xchgl %0, %1"
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: "=r"(r), "=m"(m->lock)
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: "0"(1), "m"(m->lock)
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: "memory");
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return r;
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}
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static inline int mutex_unlock(mutex_t *m) {
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m->lock = 0;
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__asm __volatile ("" : "=m" (m->lock) : "0" (m->lock));
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return 0;
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}
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#else
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/* Normal pthread mutex. */
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typedef pthread_mutex_t mutex_t;
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#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
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#define mutex_init(m) pthread_mutex_init(m, NULL)
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#define mutex_lock(m) pthread_mutex_lock(m)
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#define mutex_trylock(m) pthread_mutex_trylock(m)
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#define mutex_unlock(m) pthread_mutex_unlock(m)
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#endif /* (__i386__ || __x86_64__) && __GNUC__ && !USE_NO_SPINLOCKS */
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/* thread specific data */
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#if defined(__sgi) || defined(USE_TSD_DATA_HACK)
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/* Hack for thread-specific data, e.g. on Irix 6.x. We can't use
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pthread_setspecific because that function calls malloc() itself.
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The hack only works when pthread_t can be converted to an integral
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type. */
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typedef void *tsd_key_t[256];
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#define tsd_key_create(key, destr) do { \
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int i; \
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for(i=0; i<256; i++) (*key)[i] = 0; \
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} while(0)
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#define tsd_setspecific(key, data) \
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(key[(unsigned)pthread_self() % 256] = (data))
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#define tsd_getspecific(key, vptr) \
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(vptr = key[(unsigned)pthread_self() % 256])
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#else
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typedef pthread_key_t tsd_key_t;
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#define tsd_key_create(key, destr) pthread_key_create(key, destr)
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#define tsd_setspecific(key, data) pthread_setspecific(key, data)
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#define tsd_getspecific(key, vptr) (vptr = pthread_getspecific(key))
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#endif
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/* at fork */
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#define thread_atfork(prepare, parent, child) \
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pthread_atfork(prepare, parent, child)
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#elif USE_THR /* Solaris threads */
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#include <thread.h>
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typedef thread_t thread_id;
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#define MUTEX_INITIALIZER { 0 }
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#define mutex_init(m) mutex_init(m, USYNC_THREAD, NULL)
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/*
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* Hack for thread-specific data on Solaris. We can't use thr_setspecific
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* because that function calls malloc() itself.
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*/
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typedef void *tsd_key_t[256];
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#define tsd_key_create(key, destr) do { \
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int i; \
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for(i=0; i<256; i++) (*key)[i] = 0; \
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} while(0)
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#define tsd_setspecific(key, data) (key[(unsigned)thr_self() % 256] = (data))
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#define tsd_getspecific(key, vptr) (vptr = key[(unsigned)thr_self() % 256])
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#define thread_atfork(prepare, parent, child) do {} while(0)
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#elif USE_SPROC /* SGI sproc() threads */
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#include <sys/wait.h>
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#include <sys/types.h>
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#include <sys/prctl.h>
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#include <abi_mutex.h>
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typedef int thread_id;
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typedef abilock_t mutex_t;
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#define MUTEX_INITIALIZER { 0 }
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#define mutex_init(m) init_lock(m)
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#define mutex_lock(m) (spin_lock(m), 0)
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#define mutex_trylock(m) acquire_lock(m)
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#define mutex_unlock(m) release_lock(m)
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typedef int tsd_key_t;
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int tsd_key_next;
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#define tsd_key_create(key, destr) ((*key) = tsd_key_next++)
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#define tsd_setspecific(key, data) (((void **)(&PRDA->usr_prda))[key] = data)
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#define tsd_getspecific(key, vptr) (vptr = ((void **)(&PRDA->usr_prda))[key])
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#define thread_atfork(prepare, parent, child) do {} while(0)
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#else /* no _LIBC or USE_... are defined */
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#define NO_THREADS
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#endif /* defined(_LIBC) */
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#ifdef NO_THREADS /* No threads, provide dummy macros */
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typedef int thread_id;
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/* The mutex functions used to do absolutely nothing, i.e. lock,
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trylock and unlock would always just return 0. However, even
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without any concurrently active threads, a mutex can be used
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legitimately as an `in use' flag. To make the code that is
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protected by a mutex async-signal safe, these macros would have to
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be based on atomic test-and-set operations, for example. */
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typedef int mutex_t;
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#define MUTEX_INITIALIZER 0
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#define mutex_init(m) (*(m) = 0)
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#define mutex_lock(m) ((*(m) = 1), 0)
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#define mutex_trylock(m) (*(m) ? 1 : ((*(m) = 1), 0))
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#define mutex_unlock(m) (*(m) = 0)
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typedef void *tsd_key_t;
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#define tsd_key_create(key, destr) do {} while(0)
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#define tsd_setspecific(key, data) ((key) = (data))
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#define tsd_getspecific(key, vptr) (vptr = (key))
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#define thread_atfork(prepare, parent, child) do {} while(0)
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#endif /* defined(NO_THREADS) */
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#endif /* !defined(_THREAD_M_H) */
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