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-rw-r--r--lib/glthread/lock.h791
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diff --git a/lib/glthread/lock.h b/lib/glthread/lock.h
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+/* Locking in multithreaded situations.
+ Copyright (C) 2005-2022 Free Software Foundation, Inc.
+
+ This file 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.
+
+ This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-win32.h. */
+
+/* This file contains locking primitives for use with a given thread library.
+ It does not contain primitives for creating threads or for other
+ synchronization primitives.
+
+ Normal (non-recursive) locks:
+ Type: gl_lock_t
+ Declaration: gl_lock_define(extern, name)
+ Initializer: gl_lock_define_initialized(, name)
+ Initialization: gl_lock_init (name);
+ Taking the lock: gl_lock_lock (name);
+ Releasing the lock: gl_lock_unlock (name);
+ De-initialization: gl_lock_destroy (name);
+ Equivalent functions with control of error handling:
+ Initialization: err = glthread_lock_init (&name);
+ Taking the lock: err = glthread_lock_lock (&name);
+ Releasing the lock: err = glthread_lock_unlock (&name);
+ De-initialization: err = glthread_lock_destroy (&name);
+
+ Read-Write (non-recursive) locks:
+ Type: gl_rwlock_t
+ Declaration: gl_rwlock_define(extern, name)
+ Initializer: gl_rwlock_define_initialized(, name)
+ Initialization: gl_rwlock_init (name);
+ Taking the lock: gl_rwlock_rdlock (name);
+ gl_rwlock_wrlock (name);
+ Releasing the lock: gl_rwlock_unlock (name);
+ De-initialization: gl_rwlock_destroy (name);
+ Equivalent functions with control of error handling:
+ Initialization: err = glthread_rwlock_init (&name);
+ Taking the lock: err = glthread_rwlock_rdlock (&name);
+ err = glthread_rwlock_wrlock (&name);
+ Releasing the lock: err = glthread_rwlock_unlock (&name);
+ De-initialization: err = glthread_rwlock_destroy (&name);
+
+ Recursive locks:
+ Type: gl_recursive_lock_t
+ Declaration: gl_recursive_lock_define(extern, name)
+ Initializer: gl_recursive_lock_define_initialized(, name)
+ Initialization: gl_recursive_lock_init (name);
+ Taking the lock: gl_recursive_lock_lock (name);
+ Releasing the lock: gl_recursive_lock_unlock (name);
+ De-initialization: gl_recursive_lock_destroy (name);
+ Equivalent functions with control of error handling:
+ Initialization: err = glthread_recursive_lock_init (&name);
+ Taking the lock: err = glthread_recursive_lock_lock (&name);
+ Releasing the lock: err = glthread_recursive_lock_unlock (&name);
+ De-initialization: err = glthread_recursive_lock_destroy (&name);
+
+ Once-only execution:
+ Type: gl_once_t
+ Initializer: gl_once_define(extern, name)
+ Execution: gl_once (name, initfunction);
+ Equivalent functions with control of error handling:
+ Execution: err = glthread_once (&name, initfunction);
+*/
+
+
+#ifndef _LOCK_H
+#define _LOCK_H
+
+#include <errno.h>
+#include <stdlib.h>
+
+#if !defined c11_threads_in_use
+# if HAVE_THREADS_H && USE_POSIX_THREADS_FROM_LIBC
+# define c11_threads_in_use() 1
+# elif HAVE_THREADS_H && USE_POSIX_THREADS_WEAK
+# include <threads.h>
+# pragma weak thrd_exit
+# define c11_threads_in_use() (thrd_exit != NULL)
+# else
+# define c11_threads_in_use() 0
+# endif
+#endif
+
+/* ========================================================================= */
+
+#if USE_ISOC_THREADS || USE_ISOC_AND_POSIX_THREADS
+
+/* Use the ISO C threads library. */
+
+# include <threads.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef struct
+ {
+ int volatile init_needed;
+ once_flag init_once;
+ void (*init_func) (void);
+ mtx_t mutex;
+ }
+ gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_lock_t NAME;
+# define gl_lock_define_initialized(STORAGECLASS, NAME) \
+ static void _atomic_init_##NAME (void); \
+ STORAGECLASS gl_lock_t NAME = \
+ { 1, ONCE_FLAG_INIT, _atomic_init_##NAME }; \
+ static void _atomic_init_##NAME (void) \
+ { \
+ if (glthread_lock_init (&(NAME))) \
+ abort (); \
+ }
+extern int glthread_lock_init (gl_lock_t *lock);
+extern int glthread_lock_lock (gl_lock_t *lock);
+extern int glthread_lock_unlock (gl_lock_t *lock);
+extern int glthread_lock_destroy (gl_lock_t *lock);
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef struct
+ {
+ int volatile init_needed;
+ once_flag init_once;
+ void (*init_func) (void);
+ mtx_t lock; /* protects the remaining fields */
+ cnd_t waiting_readers; /* waiting readers */
+ cnd_t waiting_writers; /* waiting writers */
+ unsigned int waiting_writers_count; /* number of waiting writers */
+ int runcount; /* number of readers running, or -1 when a writer runs */
+ }
+ gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+ static void _atomic_init_##NAME (void); \
+ STORAGECLASS gl_rwlock_t NAME = \
+ { 1, ONCE_FLAG_INIT, _atomic_init_##NAME }; \
+ static void _atomic_init_##NAME (void) \
+ { \
+ if (glthread_rwlock_init (&(NAME))) \
+ abort (); \
+ }
+extern int glthread_rwlock_init (gl_rwlock_t *lock);
+extern int glthread_rwlock_rdlock (gl_rwlock_t *lock);
+extern int glthread_rwlock_wrlock (gl_rwlock_t *lock);
+extern int glthread_rwlock_unlock (gl_rwlock_t *lock);
+extern int glthread_rwlock_destroy (gl_rwlock_t *lock);
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+typedef struct
+ {
+ int volatile init_needed;
+ once_flag init_once;
+ void (*init_func) (void);
+ mtx_t mutex;
+ }
+ gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME;
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+ static void _atomic_init_##NAME (void); \
+ STORAGECLASS gl_recursive_lock_t NAME = \
+ { 1, ONCE_FLAG_INIT, _atomic_init_##NAME }; \
+ static void _atomic_init_##NAME (void) \
+ { \
+ if (glthread_recursive_lock_init (&(NAME))) \
+ abort (); \
+ }
+extern int glthread_recursive_lock_init (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_lock (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_unlock (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_destroy (gl_recursive_lock_t *lock);
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef once_flag gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+ STORAGECLASS once_flag NAME = ONCE_FLAG_INIT;
+# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
+ (call_once (ONCE_CONTROL, INITFUNCTION), 0)
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_POSIX_THREADS
+
+/* Use the POSIX threads library. */
+
+# include <pthread.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+# if PTHREAD_IN_USE_DETECTION_HARD
+
+/* The pthread_in_use() detection needs to be done at runtime. */
+# define pthread_in_use() \
+ glthread_in_use ()
+extern int glthread_in_use (void);
+
+# endif
+
+# if USE_POSIX_THREADS_WEAK
+
+/* Use weak references to the POSIX threads library. */
+
+/* Weak references avoid dragging in external libraries if the other parts
+ of the program don't use them. Here we use them, because we don't want
+ every program that uses libintl to depend on libpthread. This assumes
+ that libpthread would not be loaded after libintl; i.e. if libintl is
+ loaded first, by an executable that does not depend on libpthread, and
+ then a module is dynamically loaded that depends on libpthread, libintl
+ will not be multithread-safe. */
+
+/* The way to test at runtime whether libpthread is present is to test
+ whether a function pointer's value, such as &pthread_mutex_init, is
+ non-NULL. However, some versions of GCC have a bug through which, in
+ PIC mode, &foo != NULL always evaluates to true if there is a direct
+ call to foo(...) in the same function. To avoid this, we test the
+ address of a function in libpthread that we don't use. */
+
+# pragma weak pthread_mutex_init
+# pragma weak pthread_mutex_lock
+# pragma weak pthread_mutex_unlock
+# pragma weak pthread_mutex_destroy
+# pragma weak pthread_rwlock_init
+# pragma weak pthread_rwlock_rdlock
+# pragma weak pthread_rwlock_wrlock
+# pragma weak pthread_rwlock_unlock
+# pragma weak pthread_rwlock_destroy
+# pragma weak pthread_once
+# pragma weak pthread_cond_init
+# pragma weak pthread_cond_wait
+# pragma weak pthread_cond_signal
+# pragma weak pthread_cond_broadcast
+# pragma weak pthread_cond_destroy
+# pragma weak pthread_mutexattr_init
+# pragma weak pthread_mutexattr_settype
+# pragma weak pthread_mutexattr_destroy
+# pragma weak pthread_rwlockattr_init
+# if __GNU_LIBRARY__ > 1
+# pragma weak pthread_rwlockattr_setkind_np
+# endif
+# pragma weak pthread_rwlockattr_destroy
+# ifndef pthread_self
+# pragma weak pthread_self
+# endif
+
+# if !PTHREAD_IN_USE_DETECTION_HARD
+ /* Considering all platforms with USE_POSIX_THREADS_WEAK, only few symbols
+ can be used to determine whether libpthread is in use. These are:
+ pthread_mutexattr_gettype
+ pthread_rwlockattr_destroy
+ pthread_rwlockattr_init
+ */
+# pragma weak pthread_mutexattr_gettype
+# define pthread_in_use() \
+ (pthread_mutexattr_gettype != NULL || c11_threads_in_use ())
+# endif
+
+# else
+
+# if !PTHREAD_IN_USE_DETECTION_HARD
+# define pthread_in_use() 1
+# endif
+
+# endif
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef pthread_mutex_t gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_mutex_t NAME;
+# define gl_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_mutex_t NAME = gl_lock_initializer;
+# define gl_lock_initializer \
+ PTHREAD_MUTEX_INITIALIZER
+# define glthread_lock_init(LOCK) \
+ (pthread_in_use () ? pthread_mutex_init (LOCK, NULL) : 0)
+# define glthread_lock_lock(LOCK) \
+ (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0)
+# define glthread_lock_unlock(LOCK) \
+ (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0)
+# define glthread_lock_destroy(LOCK) \
+ (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0)
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+# if HAVE_PTHREAD_RWLOCK && (HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER || (defined PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP && (__GNU_LIBRARY__ > 1)))
+
+# if defined PTHREAD_RWLOCK_INITIALIZER || defined PTHREAD_RWLOCK_INITIALIZER_NP
+
+typedef pthread_rwlock_t gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_rwlock_t NAME = gl_rwlock_initializer;
+# if HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
+# if defined PTHREAD_RWLOCK_INITIALIZER
+# define gl_rwlock_initializer \
+ PTHREAD_RWLOCK_INITIALIZER
+# else
+# define gl_rwlock_initializer \
+ PTHREAD_RWLOCK_INITIALIZER_NP
+# endif
+# define glthread_rwlock_init(LOCK) \
+ (pthread_in_use () ? pthread_rwlock_init (LOCK, NULL) : 0)
+# else /* glibc with bug https://sourceware.org/bugzilla/show_bug.cgi?id=13701 */
+# define gl_rwlock_initializer \
+ PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP
+# define glthread_rwlock_init(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_init_for_glibc (LOCK) : 0)
+extern int glthread_rwlock_init_for_glibc (pthread_rwlock_t *lock);
+# endif
+# define glthread_rwlock_rdlock(LOCK) \
+ (pthread_in_use () ? pthread_rwlock_rdlock (LOCK) : 0)
+# define glthread_rwlock_wrlock(LOCK) \
+ (pthread_in_use () ? pthread_rwlock_wrlock (LOCK) : 0)
+# define glthread_rwlock_unlock(LOCK) \
+ (pthread_in_use () ? pthread_rwlock_unlock (LOCK) : 0)
+# define glthread_rwlock_destroy(LOCK) \
+ (pthread_in_use () ? pthread_rwlock_destroy (LOCK) : 0)
+
+# else
+
+typedef struct
+ {
+ int initialized;
+ pthread_mutex_t guard; /* protects the initialization */
+ pthread_rwlock_t rwlock; /* read-write lock */
+ }
+ gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
+# define gl_rwlock_initializer \
+ { 0, PTHREAD_MUTEX_INITIALIZER }
+# define glthread_rwlock_init(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0)
+# define glthread_rwlock_rdlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_wrlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_unlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_destroy(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0)
+extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock);
+
+# endif
+
+# else
+
+typedef struct
+ {
+ pthread_mutex_t lock; /* protects the remaining fields */
+ pthread_cond_t waiting_readers; /* waiting readers */
+ pthread_cond_t waiting_writers; /* waiting writers */
+ unsigned int waiting_writers_count; /* number of waiting writers */
+ int runcount; /* number of readers running, or -1 when a writer runs */
+ }
+ gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
+# define gl_rwlock_initializer \
+ { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0 }
+# define glthread_rwlock_init(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0)
+# define glthread_rwlock_rdlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_wrlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_unlock(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0)
+# define glthread_rwlock_destroy(LOCK) \
+ (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0)
+extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock);
+extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock);
+
+# endif
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+# if HAVE_PTHREAD_MUTEX_RECURSIVE
+
+# if defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
+
+typedef pthread_mutex_t gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_mutex_t NAME;
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_mutex_t NAME = gl_recursive_lock_initializer;
+# ifdef PTHREAD_RECURSIVE_MUTEX_INITIALIZER
+# define gl_recursive_lock_initializer \
+ PTHREAD_RECURSIVE_MUTEX_INITIALIZER
+# else
+# define gl_recursive_lock_initializer \
+ PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
+# endif
+# define glthread_recursive_lock_init(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_lock(LOCK) \
+ (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0)
+# define glthread_recursive_lock_unlock(LOCK) \
+ (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0)
+# define glthread_recursive_lock_destroy(LOCK) \
+ (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0)
+extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
+
+# else
+
+typedef struct
+ {
+ pthread_mutex_t recmutex; /* recursive mutex */
+ pthread_mutex_t guard; /* protects the initialization */
+ int initialized;
+ }
+ gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME;
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
+# define gl_recursive_lock_initializer \
+ { PTHREAD_MUTEX_INITIALIZER, PTHREAD_MUTEX_INITIALIZER, 0 }
+# define glthread_recursive_lock_init(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_lock(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_unlock(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_destroy(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0)
+extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock);
+
+# endif
+
+# else
+
+/* Old versions of POSIX threads on Solaris did not have recursive locks.
+ We have to implement them ourselves. */
+
+typedef struct
+ {
+ pthread_mutex_t mutex;
+ pthread_t owner;
+ unsigned long depth;
+ }
+ gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME;
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
+# define gl_recursive_lock_initializer \
+ { PTHREAD_MUTEX_INITIALIZER, (pthread_t) 0, 0 }
+# define glthread_recursive_lock_init(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_lock(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_unlock(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0)
+# define glthread_recursive_lock_destroy(LOCK) \
+ (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0)
+extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock);
+extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock);
+
+# endif
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef pthread_once_t gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+ STORAGECLASS pthread_once_t NAME = PTHREAD_ONCE_INIT;
+# if PTHREAD_IN_USE_DETECTION_HARD || USE_POSIX_THREADS_WEAK
+# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
+ (pthread_in_use () \
+ ? pthread_once (ONCE_CONTROL, INITFUNCTION) \
+ : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0))
+# else
+# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
+ (pthread_in_use () \
+ ? glthread_once_multithreaded (ONCE_CONTROL, INITFUNCTION) \
+ : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0))
+extern int glthread_once_multithreaded (pthread_once_t *once_control,
+ void (*init_function) (void));
+# endif
+extern int glthread_once_singlethreaded (pthread_once_t *once_control);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_WINDOWS_THREADS
+
+# define WIN32_LEAN_AND_MEAN /* avoid including junk */
+# include <windows.h>
+
+# include "windows-mutex.h"
+# include "windows-rwlock.h"
+# include "windows-recmutex.h"
+# include "windows-once.h"
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/* We can use CRITICAL_SECTION directly, rather than the native Windows Event,
+ Mutex, Semaphore types, because
+ - we need only to synchronize inside a single process (address space),
+ not inter-process locking,
+ - we don't need to support trylock operations. (TryEnterCriticalSection
+ does not work on Windows 95/98/ME. Packages that need trylock usually
+ define their own mutex type.) */
+
+/* There is no way to statically initialize a CRITICAL_SECTION. It needs
+ to be done lazily, once only. For this we need spinlocks. */
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef glwthread_mutex_t gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_lock_t NAME;
+# define gl_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_lock_t NAME = gl_lock_initializer;
+# define gl_lock_initializer \
+ GLWTHREAD_MUTEX_INIT
+# define glthread_lock_init(LOCK) \
+ (glwthread_mutex_init (LOCK), 0)
+# define glthread_lock_lock(LOCK) \
+ glwthread_mutex_lock (LOCK)
+# define glthread_lock_unlock(LOCK) \
+ glwthread_mutex_unlock (LOCK)
+# define glthread_lock_destroy(LOCK) \
+ glwthread_mutex_destroy (LOCK)
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef glwthread_rwlock_t gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
+# define gl_rwlock_initializer \
+ GLWTHREAD_RWLOCK_INIT
+# define glthread_rwlock_init(LOCK) \
+ (glwthread_rwlock_init (LOCK), 0)
+# define glthread_rwlock_rdlock(LOCK) \
+ glwthread_rwlock_rdlock (LOCK)
+# define glthread_rwlock_wrlock(LOCK) \
+ glwthread_rwlock_wrlock (LOCK)
+# define glthread_rwlock_unlock(LOCK) \
+ glwthread_rwlock_unlock (LOCK)
+# define glthread_rwlock_destroy(LOCK) \
+ glwthread_rwlock_destroy (LOCK)
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+typedef glwthread_recmutex_t gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME;
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+ STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
+# define gl_recursive_lock_initializer \
+ GLWTHREAD_RECMUTEX_INIT
+# define glthread_recursive_lock_init(LOCK) \
+ (glwthread_recmutex_init (LOCK), 0)
+# define glthread_recursive_lock_lock(LOCK) \
+ glwthread_recmutex_lock (LOCK)
+# define glthread_recursive_lock_unlock(LOCK) \
+ glwthread_recmutex_unlock (LOCK)
+# define glthread_recursive_lock_destroy(LOCK) \
+ glwthread_recmutex_destroy (LOCK)
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef glwthread_once_t gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_once_t NAME = GLWTHREAD_ONCE_INIT;
+# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
+ (glwthread_once (ONCE_CONTROL, INITFUNCTION), 0)
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
+
+/* ========================================================================= */
+
+#if !(USE_ISOC_THREADS || USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS || USE_WINDOWS_THREADS)
+
+/* Provide dummy implementation if threads are not supported. */
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef int gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME)
+# define gl_lock_define_initialized(STORAGECLASS, NAME)
+# define glthread_lock_init(NAME) 0
+# define glthread_lock_lock(NAME) 0
+# define glthread_lock_unlock(NAME) 0
+# define glthread_lock_destroy(NAME) 0
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef int gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME)
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME)
+# define glthread_rwlock_init(NAME) 0
+# define glthread_rwlock_rdlock(NAME) 0
+# define glthread_rwlock_wrlock(NAME) 0
+# define glthread_rwlock_unlock(NAME) 0
+# define glthread_rwlock_destroy(NAME) 0
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+typedef int gl_recursive_lock_t;
+# define gl_recursive_lock_define(STORAGECLASS, NAME)
+# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME)
+# define glthread_recursive_lock_init(NAME) 0
+# define glthread_recursive_lock_lock(NAME) 0
+# define glthread_recursive_lock_unlock(NAME) 0
+# define glthread_recursive_lock_destroy(NAME) 0
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef int gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+ STORAGECLASS gl_once_t NAME = 0;
+# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
+ (*(ONCE_CONTROL) == 0 ? (*(ONCE_CONTROL) = ~ 0, INITFUNCTION (), 0) : 0)
+
+#endif
+
+/* ========================================================================= */
+
+/* Macros with built-in error handling. */
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+#define gl_lock_init(NAME) \
+ do \
+ { \
+ if (glthread_lock_init (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_lock_lock(NAME) \
+ do \
+ { \
+ if (glthread_lock_lock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_lock_unlock(NAME) \
+ do \
+ { \
+ if (glthread_lock_unlock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_lock_destroy(NAME) \
+ do \
+ { \
+ if (glthread_lock_destroy (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+#define gl_rwlock_init(NAME) \
+ do \
+ { \
+ if (glthread_rwlock_init (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_rwlock_rdlock(NAME) \
+ do \
+ { \
+ if (glthread_rwlock_rdlock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_rwlock_wrlock(NAME) \
+ do \
+ { \
+ if (glthread_rwlock_wrlock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_rwlock_unlock(NAME) \
+ do \
+ { \
+ if (glthread_rwlock_unlock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_rwlock_destroy(NAME) \
+ do \
+ { \
+ if (glthread_rwlock_destroy (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+#define gl_recursive_lock_init(NAME) \
+ do \
+ { \
+ if (glthread_recursive_lock_init (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_recursive_lock_lock(NAME) \
+ do \
+ { \
+ if (glthread_recursive_lock_lock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_recursive_lock_unlock(NAME) \
+ do \
+ { \
+ if (glthread_recursive_lock_unlock (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+#define gl_recursive_lock_destroy(NAME) \
+ do \
+ { \
+ if (glthread_recursive_lock_destroy (&NAME)) \
+ abort (); \
+ } \
+ while (0)
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+#define gl_once(NAME, INITFUNCTION) \
+ do \
+ { \
+ if (glthread_once (&NAME, INITFUNCTION)) \
+ abort (); \
+ } \
+ while (0)
+
+/* ========================================================================= */
+
+#endif /* _LOCK_H */