libgcc/gthr.h

/* Threads compatibility routines for libgcc2.  */
/* Compile this one with gcc.  */
/* Copyright (C) 1997-2021 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC 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 General Public License
for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#ifndef GCC_GTHR_H
#define GCC_GTHR_H

#ifndef HIDE_EXPORTS
#pragma GCC visibility push(default)
#endif

/* If this file is compiled with threads support, it must
       #define __GTHREADS 1
   to indicate that threads support is present.  Also it has define
   function
     int __gthread_active_p ()
   that returns 1 if thread system is active, 0 if not.

   The threads interface must define the following types:
     __gthread_key_t
     __gthread_once_t
     __gthread_mutex_t
     __gthread_recursive_mutex_t

   The threads interface must define the following macros:

     __GTHREAD_ONCE_INIT
     		to initialize __gthread_once_t
     __GTHREAD_MUTEX_INIT
     		to initialize __gthread_mutex_t to get a fast
		non-recursive mutex.
     __GTHREAD_MUTEX_INIT_FUNCTION
		to initialize __gthread_mutex_t to get a fast
		non-recursive mutex.
		Define this to a function which looks like this:
		  void __GTHREAD_MUTEX_INIT_FUNCTION (__gthread_mutex_t *)
     		Some systems can't initialize a mutex without a
		function call.  Don't define __GTHREAD_MUTEX_INIT in this case.
     __GTHREAD_RECURSIVE_MUTEX_INIT
     __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
     		as above, but for a recursive mutex.

   The threads interface must define the following static functions:

     int __gthread_once (__gthread_once_t *once, void (*func) ())

     int __gthread_key_create (__gthread_key_t *keyp, void (*dtor) (void *))
     int __gthread_key_delete (__gthread_key_t key)

     void *__gthread_getspecific (__gthread_key_t key)
     int __gthread_setspecific (__gthread_key_t key, const void *ptr)

     int __gthread_mutex_destroy (__gthread_mutex_t *mutex);
     int __gthread_recursive_mutex_destroy (__gthread_recursive_mutex_t *mutex);

     int __gthread_mutex_lock (__gthread_mutex_t *mutex);
     int __gthread_mutex_trylock (__gthread_mutex_t *mutex);
     int __gthread_mutex_unlock (__gthread_mutex_t *mutex);

     int __gthread_recursive_mutex_lock (__gthread_recursive_mutex_t *mutex);
     int __gthread_recursive_mutex_trylock (__gthread_recursive_mutex_t *mutex);
     int __gthread_recursive_mutex_unlock (__gthread_recursive_mutex_t *mutex);

   The following are supported in POSIX threads only. They are required to
   fix a deadlock in static initialization inside libsupc++. The header file
   gthr-posix.h defines a symbol __GTHREAD_HAS_COND to signify that these extra
   features are supported.

   Types:
     __gthread_cond_t

   Macros:
     __GTHREAD_COND_INIT
     __GTHREAD_COND_INIT_FUNCTION

   Interface:
     int __gthread_cond_broadcast (__gthread_cond_t *cond);
     int __gthread_cond_wait (__gthread_cond_t *cond, __gthread_mutex_t *mutex);
     int __gthread_cond_wait_recursive (__gthread_cond_t *cond,
					__gthread_recursive_mutex_t *mutex);

   All functions returning int should return zero on success or the error
   number.  If the operation is not supported, -1 is returned.

   If the following are also defined, you should
     #define __GTHREADS_CXX0X 1
   to enable the c++0x thread library.

   Types:
     __gthread_t
     __gthread_time_t

   Interface:
     int __gthread_create (__gthread_t *thread, void *(*func) (void*),
                           void *args);
     int __gthread_join (__gthread_t thread, void **value_ptr);
     int __gthread_detach (__gthread_t thread);
     int __gthread_equal (__gthread_t t1, __gthread_t t2);
     __gthread_t __gthread_self (void);
     int __gthread_yield (void);

     int __gthread_mutex_timedlock (__gthread_mutex_t *m,
                                    const __gthread_time_t *abs_timeout);
     int __gthread_recursive_mutex_timedlock (__gthread_recursive_mutex_t *m,
                                          const __gthread_time_t *abs_time);

     int __gthread_cond_signal (__gthread_cond_t *cond);
     int __gthread_cond_timedwait (__gthread_cond_t *cond,
                                   __gthread_mutex_t *mutex,
                                   const __gthread_time_t *abs_timeout);

*/

#if SUPPORTS_WEAK
/* The pe-coff weak support isn't fully compatible to ELF's weak.
   For static libraries it might would work, but as we need to deal
   with shared versions too, we disable it for mingw-targets.  */
#ifdef __MINGW32__
#undef GTHREAD_USE_WEAK
#define GTHREAD_USE_WEAK 0
#endif

#ifndef GTHREAD_USE_WEAK
#define GTHREAD_USE_WEAK 1
#endif
#endif
#include "gthr-default.h"

#ifndef HIDE_EXPORTS
#pragma GCC visibility pop
#endif

#endif /* ! GCC_GTHR_H */