229 lines
7.2 KiB
C
229 lines
7.2 KiB
C
/* Thread-local storage in multithreaded situations.
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Copyright (C) 2005, 2007-2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2005. */
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/* This file contains thread-local storage primitives for use with a given
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thread library. It does not contain primitives for creating threads or
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for other multithreading primitives.
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Type: gl_tls_key_t
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Initialization: gl_tls_key_init (name, destructor);
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Getting per-thread value: gl_tls_get (name)
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Setting per-thread value: gl_tls_set (name, pointer);
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De-initialization: gl_tls_key_destroy (name);
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Equivalent functions with control of error handling:
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Initialization: err = glthread_tls_key_init (&name, destructor);
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Setting per-thread value: err = glthread_tls_set (&name, pointer);
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De-initialization: err = glthread_tls_key_destroy (&name);
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A per-thread value is of type 'void *'.
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A destructor is a function pointer of type 'void (*) (void *)', called
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when a thread exits, and taking the last per-thread value as argument. It
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is unspecified whether the destructor function is called when the last
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per-thread value is NULL. On some platforms, the destructor function is
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not called at all.
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*/
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#ifndef _TLS_H
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#define _TLS_H
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#include <errno.h>
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#include <stdlib.h>
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#if !defined c11_threads_in_use
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# if HAVE_THREADS_H && USE_POSIX_THREADS_WEAK
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# include <threads.h>
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# pragma weak thrd_exit
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# define c11_threads_in_use() (thrd_exit != NULL)
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# else
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# define c11_threads_in_use() 0
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# endif
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#endif
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/* ========================================================================= */
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#if USE_ISOC_THREADS || USE_ISOC_AND_POSIX_THREADS
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/* Use the ISO C threads library. */
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# include <threads.h>
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/* ------------------------- gl_tls_key_t datatype ------------------------- */
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typedef tss_t gl_tls_key_t;
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# define glthread_tls_key_init(KEY, DESTRUCTOR) \
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(tss_create (KEY, DESTRUCTOR) != thrd_success ? EAGAIN : 0)
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# define gl_tls_get(NAME) \
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tss_get (NAME)
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# define glthread_tls_set(KEY, POINTER) \
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(tss_set (*(KEY), (POINTER)) != thrd_success ? ENOMEM : 0)
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# define glthread_tls_key_destroy(KEY) \
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(tss_delete (*(KEY)), 0)
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#endif
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/* ========================================================================= */
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#if USE_POSIX_THREADS
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/* Use the POSIX threads library. */
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# include <pthread.h>
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# if PTHREAD_IN_USE_DETECTION_HARD
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/* The pthread_in_use() detection needs to be done at runtime. */
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# define pthread_in_use() \
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glthread_in_use ()
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extern int glthread_in_use (void);
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# endif
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# if USE_POSIX_THREADS_WEAK
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/* Use weak references to the POSIX threads library. */
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# pragma weak pthread_key_create
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# pragma weak pthread_getspecific
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# pragma weak pthread_setspecific
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# pragma weak pthread_key_delete
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# ifndef pthread_self
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# pragma weak pthread_self
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# endif
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# if !PTHREAD_IN_USE_DETECTION_HARD
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# pragma weak pthread_mutexattr_gettype
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# define pthread_in_use() \
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(pthread_mutexattr_gettype != NULL || c11_threads_in_use ())
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# endif
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# else
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# if !PTHREAD_IN_USE_DETECTION_HARD
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# define pthread_in_use() 1
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# endif
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# endif
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/* ------------------------- gl_tls_key_t datatype ------------------------- */
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typedef union
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{
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void *singlethread_value;
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pthread_key_t key;
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}
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gl_tls_key_t;
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# define glthread_tls_key_init(KEY, DESTRUCTOR) \
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(pthread_in_use () \
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? pthread_key_create (&(KEY)->key, DESTRUCTOR) \
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: ((KEY)->singlethread_value = NULL, 0))
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# define gl_tls_get(NAME) \
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(pthread_in_use () \
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? pthread_getspecific ((NAME).key) \
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: (NAME).singlethread_value)
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# define glthread_tls_set(KEY, POINTER) \
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(pthread_in_use () \
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? pthread_setspecific ((KEY)->key, (POINTER)) \
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: ((KEY)->singlethread_value = (POINTER), 0))
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# define glthread_tls_key_destroy(KEY) \
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(pthread_in_use () ? pthread_key_delete ((KEY)->key) : 0)
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#endif
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/* ========================================================================= */
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#if USE_WINDOWS_THREADS
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# define WIN32_LEAN_AND_MEAN /* avoid including junk */
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# include <windows.h>
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# include "windows-tls.h"
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/* ------------------------- gl_tls_key_t datatype ------------------------- */
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typedef glwthread_tls_key_t gl_tls_key_t;
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# define glthread_tls_key_init(KEY, DESTRUCTOR) \
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glwthread_tls_key_create (KEY, DESTRUCTOR)
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# define gl_tls_get(NAME) \
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TlsGetValue (NAME)
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# define glthread_tls_set(KEY, POINTER) \
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(!TlsSetValue (*(KEY), POINTER) ? EINVAL : 0)
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# define glthread_tls_key_destroy(KEY) \
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glwthread_tls_key_delete (*(KEY))
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#endif
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/* ========================================================================= */
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#if !(USE_ISOC_THREADS || USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS || USE_WINDOWS_THREADS)
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/* Provide dummy implementation if threads are not supported. */
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/* ------------------------- gl_tls_key_t datatype ------------------------- */
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typedef struct
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{
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void *singlethread_value;
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}
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gl_tls_key_t;
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# define glthread_tls_key_init(KEY, DESTRUCTOR) \
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((KEY)->singlethread_value = NULL, \
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(void) (DESTRUCTOR), \
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0)
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# define gl_tls_get(NAME) \
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(NAME).singlethread_value
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# define glthread_tls_set(KEY, POINTER) \
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((KEY)->singlethread_value = (POINTER), 0)
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# define glthread_tls_key_destroy(KEY) \
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0
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#endif
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/* ========================================================================= */
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/* Macros with built-in error handling. */
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/* ------------------------- gl_tls_key_t datatype ------------------------- */
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#define gl_tls_key_init(NAME, DESTRUCTOR) \
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do \
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{ \
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if (glthread_tls_key_init (&NAME, DESTRUCTOR)) \
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abort (); \
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} \
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while (0)
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#define gl_tls_set(NAME, POINTER) \
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do \
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{ \
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if (glthread_tls_set (&NAME, POINTER)) \
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abort (); \
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} \
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while (0)
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#define gl_tls_key_destroy(NAME) \
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do \
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{ \
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if (glthread_tls_key_destroy (&NAME)) \
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abort (); \
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} \
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while (0)
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/* ========================================================================= */
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#endif /* _TLS_H */
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