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/* ISO C11 Standard: 7.26 - Thread support library <threads.h>.
Copyright (C) 2018-2021 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/>. */
#ifndef _THREADS_H
#define _THREADS_H 1
#include <features.h>
#include <time.h>
__BEGIN_DECLS
#include <bits/thread-shared-types.h>
#include <bits/types/struct_timespec.h>
#ifndef __cplusplus
# define thread_local _Thread_local
#endif
#define TSS_DTOR_ITERATIONS 4
typedef __tss_t tss_t;
typedef void (*tss_dtor_t) (void*);
typedef __thrd_t thrd_t;
typedef int (*thrd_start_t) (void*);
/* Exit and error codes. */
enum
{
thrd_success = 0,
thrd_busy = 1,
thrd_error = 2,
thrd_nomem = 3,
thrd_timedout = 4
};
/* Mutex types. */
enum
{
mtx_plain = 0,
mtx_recursive = 1,
mtx_timed = 2
};
typedef __once_flag once_flag;
#define ONCE_FLAG_INIT __ONCE_FLAG_INIT
typedef union
{
char __size[__SIZEOF_PTHREAD_MUTEX_T];
long int __align __LOCK_ALIGNMENT;
} mtx_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_COND_T];
__extension__ long long int __align __LOCK_ALIGNMENT;
} cnd_t;
/* Threads functions. */
/* Create a new thread executing the function __FUNC. Arguments for __FUNC
are passed through __ARG. If succesful, __THR is set to new thread
identifier. */
extern int thrd_create (thrd_t *__thr, thrd_start_t __func, void *__arg);
/* Check if __LHS and __RHS point to the same thread. */
extern int thrd_equal (thrd_t __lhs, thrd_t __rhs);
/* Return current thread identifier. */
extern thrd_t thrd_current (void);
/* Block current thread execution for at least the time pointed by
__TIME_POINT. The current thread may resume if receives a signal. In
that case, if __REMAINING is not NULL, the remaining time is stored in
the object pointed by it. */
extern int thrd_sleep (const struct timespec *__time_point,
struct timespec *__remaining);
/* Terminate current thread execution, cleaning up any thread local
storage and freeing resources. Returns the value specified in __RES. */
extern void thrd_exit (int __res) __attribute__ ((__noreturn__));
/* Detach the thread identified by __THR from the current environment
(it does not allow join or wait for it). */
extern int thrd_detach (thrd_t __thr);
/* Block current thread until execution of __THR is complete. In case that
__RES is not NULL, will store the return value of __THR when exiting. */
extern int thrd_join (thrd_t __thr, int *__res);
/* Stop current thread execution and call the scheduler to decide which
thread should execute next. The current thread may be selected by the
scheduler to keep running. */
extern void thrd_yield (void);
#ifdef __USE_EXTERN_INLINES
/* Optimizations. */
__extern_inline int
thrd_equal (thrd_t __thread1, thrd_t __thread2)
{
return __thread1 == __thread2;
}
#endif
/* Mutex functions. */
/* Creates a new mutex object with type __TYPE. If successful the new
object is pointed by __MUTEX. */
extern int mtx_init (mtx_t *__mutex, int __type);
/* Block the current thread until the mutex pointed to by __MUTEX is
unlocked. In that case current thread will not be blocked. */
extern int mtx_lock (mtx_t *__mutex);
/* Block the current thread until the mutex pointed by __MUTEX is unlocked
or time pointed by __TIME_POINT is reached. In case the mutex is unlock,
the current thread will not be blocked. */
extern int mtx_timedlock (mtx_t *__restrict __mutex,
const struct timespec *__restrict __time_point);
/* Try to lock the mutex pointed by __MUTEX without blocking. If the mutex
is free the current threads takes control of it, otherwise it returns
immediately. */
extern int mtx_trylock (mtx_t *__mutex);
/* Unlock the mutex pointed by __MUTEX. It may potentially awake other
threads waiting on this mutex. */
extern int mtx_unlock (mtx_t *__mutex);
/* Destroy the mutex object pointed by __MUTEX. */
extern void mtx_destroy (mtx_t *__mutex);
/* Call function __FUNC exactly once, even if invoked from several threads.
All calls must be made with the same __FLAGS object. */
extern void call_once (once_flag *__flag, void (*__func)(void));
/* Condition variable functions. */
/* Initialize new condition variable pointed by __COND. */
extern int cnd_init (cnd_t *__cond);
/* Unblock one thread that currently waits on condition variable pointed
by __COND. */
extern int cnd_signal (cnd_t *__cond);
/* Unblock all threads currently waiting on condition variable pointed by
__COND. */
extern int cnd_broadcast (cnd_t *__cond);
/* Block current thread on the condition variable pointed by __COND. */
extern int cnd_wait (cnd_t *__cond, mtx_t *__mutex);
/* Block current thread on the condition variable until condition variable
pointed by __COND is signaled or time pointed by __TIME_POINT is
reached. */
extern int cnd_timedwait (cnd_t *__restrict __cond,
mtx_t *__restrict __mutex,
const struct timespec *__restrict __time_point);
/* Destroy condition variable pointed by __cond and free all of its
resources. */
extern void cnd_destroy (cnd_t *__COND);
/* Thread specific storage functions. */
/* Create new thread-specific storage key and stores it in the object pointed
by __TSS_ID. If __DESTRUCTOR is not NULL, the function will be called when
the thread terminates. */
extern int tss_create (tss_t *__tss_id, tss_dtor_t __destructor);
/* Return the value held in thread-specific storage for the current thread
identified by __TSS_ID. */
extern void *tss_get (tss_t __tss_id);
/* Sets the value of the thread-specific storage identified by __TSS_ID for
the current thread to __VAL. */
extern int tss_set (tss_t __tss_id, void *__val);
/* Destroys the thread-specific storage identified by __TSS_ID. The
destructor is not called until thrd_exit is called. */
extern void tss_delete (tss_t __tss_id);
__END_DECLS
#endif /* _THREADS_H */
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