| /* Return the internal lock used by mbrtowc and mbrtoc32. |
| Copyright (C) 2019-2021 Free Software Foundation, Inc. |
| |
| This program 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 of the License, or |
| (at your option) any later version. |
| |
| This program 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Bruno Haible <bruno@clisp.org>, 2019-2020. */ |
| |
| #include <config.h> |
| |
| /* When it is known that the gl_get_mbtowc_lock function is defined |
| by a dependency library, it should not be defined here. */ |
| #if OMIT_MBTOWC_LOCK |
| |
| /* This declaration is solely to ensure that after preprocessing |
| this file is never empty. */ |
| typedef int dummy; |
| |
| #else |
| |
| /* This file defines the internal lock used by mbrtowc and mbrtoc32. |
| It is a separate compilation unit, so that only one copy of it is |
| present when linking statically. */ |
| |
| /* Prohibit renaming this symbol. */ |
| # undef gl_get_mbtowc_lock |
| |
| /* Macro for exporting a symbol (function, not variable) defined in this file, |
| when compiled into a shared library. */ |
| # ifndef DLL_EXPORTED |
| # if HAVE_VISIBILITY |
| /* Override the effect of the compiler option '-fvisibility=hidden'. */ |
| # define DLL_EXPORTED __attribute__((__visibility__("default"))) |
| # elif defined _WIN32 || defined __CYGWIN__ |
| # define DLL_EXPORTED __declspec(dllexport) |
| # else |
| # define DLL_EXPORTED |
| # endif |
| # endif |
| |
| # if defined _WIN32 && !defined __CYGWIN__ |
| |
| # define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
| # include <windows.h> |
| |
| # include "windows-initguard.h" |
| |
| /* The return type is a 'CRITICAL_SECTION *', not a 'glwthread_mutex_t *', |
| because the latter is not guaranteed to be a stable ABI in the future. */ |
| |
| /* Make sure the function gets exported from DLLs. */ |
| DLL_EXPORTED CRITICAL_SECTION *gl_get_mbtowc_lock (void); |
| |
| static glwthread_initguard_t guard = GLWTHREAD_INITGUARD_INIT; |
| static CRITICAL_SECTION lock; |
| |
| /* Returns the internal lock used by mbrtowc and mbrtoc32. */ |
| CRITICAL_SECTION * |
| gl_get_mbtowc_lock (void) |
| { |
| if (!guard.done) |
| { |
| if (InterlockedIncrement (&guard.started) == 0) |
| { |
| /* This thread is the first one to need the lock. Initialize it. */ |
| InitializeCriticalSection (&lock); |
| guard.done = 1; |
| } |
| else |
| { |
| /* Don't let guard.started grow and wrap around. */ |
| InterlockedDecrement (&guard.started); |
| /* Yield the CPU while waiting for another thread to finish |
| initializing this mutex. */ |
| while (!guard.done) |
| Sleep (0); |
| } |
| } |
| return &lock; |
| } |
| |
| # elif HAVE_PTHREAD_API |
| |
| # include <pthread.h> |
| |
| static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; |
| |
| /* Make sure the function gets exported from shared libraries. */ |
| DLL_EXPORTED pthread_mutex_t *gl_get_mbtowc_lock (void); |
| |
| /* Returns the internal lock used by mbrtowc and mbrtoc32. */ |
| pthread_mutex_t * |
| gl_get_mbtowc_lock (void) |
| { |
| return &mutex; |
| } |
| |
| # elif HAVE_THREADS_H |
| |
| # include <threads.h> |
| # include <stdlib.h> |
| |
| static int volatile init_needed = 1; |
| static once_flag init_once = ONCE_FLAG_INIT; |
| static mtx_t mutex; |
| |
| static void |
| atomic_init (void) |
| { |
| if (mtx_init (&mutex, mtx_plain) != thrd_success) |
| abort (); |
| init_needed = 0; |
| } |
| |
| /* Make sure the function gets exported from shared libraries. */ |
| DLL_EXPORTED mtx_t *gl_get_mbtowc_lock (void); |
| |
| /* Returns the internal lock used by mbrtowc and mbrtoc32. */ |
| mtx_t * |
| gl_get_mbtowc_lock (void) |
| { |
| if (init_needed) |
| call_once (&init_once, atomic_init); |
| return &mutex; |
| } |
| |
| # endif |
| |
| # if (defined _WIN32 || defined __CYGWIN__) && !defined _MSC_VER |
| /* Make sure the '__declspec(dllimport)' in mbrtowc.c and mbrtoc32.c does not |
| cause a link failure when no DLLs are involved. */ |
| # if defined _WIN64 || defined _LP64 |
| # define IMP(x) __imp_##x |
| # else |
| # define IMP(x) _imp__##x |
| # endif |
| void * IMP(gl_get_mbtowc_lock) = &gl_get_mbtowc_lock; |
| # endif |
| |
| #endif |