]> git.ipfire.org Git - thirdparty/gettext.git/commitdiff
gnulib module 'lock'.
authorBruno Haible <bruno@clisp.org>
Thu, 27 Jul 2006 12:13:48 +0000 (12:13 +0000)
committerBruno Haible <bruno@clisp.org>
Tue, 23 Jun 2009 10:13:42 +0000 (12:13 +0200)
gettext-tools/lib/lock.c [new file with mode: 0644]
gettext-tools/lib/lock.h [new file with mode: 0644]

diff --git a/gettext-tools/lib/lock.c b/gettext-tools/lib/lock.c
new file mode 100644 (file)
index 0000000..a860459
--- /dev/null
@@ -0,0 +1,924 @@
+/* Locking in multithreaded situations.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU Library General Public License as published
+   by the Free Software Foundation; either version 2, 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+   USA.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+   Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
+   gthr-win32.h.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "lock.h"
+
+/* ========================================================================= */
+
+#if USE_POSIX_THREADS
+
+/* Use the POSIX threads library.  */
+
+# if PTHREAD_IN_USE_DETECTION_HARD
+
+/* The function to be executed by a dummy thread.  */
+static void *
+dummy_thread_func (void *arg)
+{
+  return arg;
+}
+
+int
+glthread_in_use (void)
+{
+  static int tested;
+  static int result; /* 1: linked with -lpthread, 0: only with libc */
+
+  if (!tested)
+    {
+      pthread_t thread;
+
+      if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
+       /* Thread creation failed.  */
+       result = 0;
+      else
+       {
+         /* Thread creation works.  */
+         void *retval;
+         if (pthread_join (thread, &retval) != 0)
+           abort ();
+         result = 1;
+       }
+      tested = 1;
+    }
+  return result;
+}
+
+# endif
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+# if HAVE_PTHREAD_RWLOCK
+
+#  if !defined PTHREAD_RWLOCK_INITIALIZER
+
+void
+glthread_rwlock_init (gl_rwlock_t *lock)
+{
+  if (pthread_rwlock_init (&lock->rwlock, NULL) != 0)
+    abort ();
+  lock->initialized = 1;
+}
+
+void
+glthread_rwlock_rdlock (gl_rwlock_t *lock)
+{
+  if (!lock->initialized)
+    {
+      if (pthread_mutex_lock (&lock->guard) != 0)
+       abort ();
+      if (!lock->initialized)
+       glthread_rwlock_init (lock);
+      if (pthread_mutex_unlock (&lock->guard) != 0)
+       abort ();
+    }
+  if (pthread_rwlock_rdlock (&lock->rwlock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_wrlock (gl_rwlock_t *lock)
+{
+  if (!lock->initialized)
+    {
+      if (pthread_mutex_lock (&lock->guard) != 0)
+       abort ();
+      if (!lock->initialized)
+       glthread_rwlock_init (lock);
+      if (pthread_mutex_unlock (&lock->guard) != 0)
+       abort ();
+    }
+  if (pthread_rwlock_wrlock (&lock->rwlock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_unlock (gl_rwlock_t *lock)
+{
+  if (!lock->initialized)
+    abort ();
+  if (pthread_rwlock_unlock (&lock->rwlock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_destroy (gl_rwlock_t *lock)
+{
+  if (!lock->initialized)
+    abort ();
+  if (pthread_rwlock_destroy (&lock->rwlock) != 0)
+    abort ();
+  lock->initialized = 0;
+}
+
+#  endif
+
+# else
+
+void
+glthread_rwlock_init (gl_rwlock_t *lock)
+{
+  if (pthread_mutex_init (&lock->lock, NULL) != 0)
+    abort ();
+  if (pthread_cond_init (&lock->waiting_readers, NULL) != 0)
+    abort ();
+  if (pthread_cond_init (&lock->waiting_writers, NULL) != 0)
+    abort ();
+  lock->waiting_writers_count = 0;
+  lock->runcount = 0;
+}
+
+void
+glthread_rwlock_rdlock (gl_rwlock_t *lock)
+{
+  if (pthread_mutex_lock (&lock->lock) != 0)
+    abort ();
+  /* Test whether only readers are currently running, and whether the runcount
+     field will not overflow.  */
+  /* POSIX says: "It is implementation-defined whether the calling thread
+     acquires the lock when a writer does not hold the lock and there are
+     writers blocked on the lock."  Let's say, no: give the writers a higher
+     priority.  */
+  while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+        waiting_readers.  */
+      if (pthread_cond_wait (&lock->waiting_readers, &lock->lock) != 0)
+       abort ();
+    }
+  lock->runcount++;
+  if (pthread_mutex_unlock (&lock->lock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_wrlock (gl_rwlock_t *lock)
+{
+  if (pthread_mutex_lock (&lock->lock) != 0)
+    abort ();
+  /* Test whether no readers or writers are currently running.  */
+  while (!(lock->runcount == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+        waiting_writers.  */
+      lock->waiting_writers_count++;
+      if (pthread_cond_wait (&lock->waiting_writers, &lock->lock) != 0)
+       abort ();
+      lock->waiting_writers_count--;
+    }
+  lock->runcount--; /* runcount becomes -1 */
+  if (pthread_mutex_unlock (&lock->lock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_unlock (gl_rwlock_t *lock)
+{
+  if (pthread_mutex_lock (&lock->lock) != 0)
+    abort ();
+  if (lock->runcount < 0)
+    {
+      /* Drop a writer lock.  */
+      if (!(lock->runcount == -1))
+       abort ();
+      lock->runcount = 0;
+    }
+  else
+    {
+      /* Drop a reader lock.  */
+      if (!(lock->runcount > 0))
+       abort ();
+      lock->runcount--;
+    }
+  if (lock->runcount == 0)
+    {
+      /* POSIX recommends that "write locks shall take precedence over read
+        locks", to avoid "writer starvation".  */
+      if (lock->waiting_writers_count > 0)
+       {
+         /* Wake up one of the waiting writers.  */
+         if (pthread_cond_signal (&lock->waiting_writers) != 0)
+           abort ();
+       }
+      else
+       {
+         /* Wake up all waiting readers.  */
+         if (pthread_cond_broadcast (&lock->waiting_readers) != 0)
+           abort ();
+       }
+    }
+  if (pthread_mutex_unlock (&lock->lock) != 0)
+    abort ();
+}
+
+void
+glthread_rwlock_destroy (gl_rwlock_t *lock)
+{
+  if (pthread_mutex_destroy (&lock->lock) != 0)
+    abort ();
+  if (pthread_cond_destroy (&lock->waiting_readers) != 0)
+    abort ();
+  if (pthread_cond_destroy (&lock->waiting_writers) != 0)
+    abort ();
+}
+
+# endif
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+# if HAVE_PTHREAD_MUTEX_RECURSIVE
+
+#  if !(defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP)
+
+void
+glthread_recursive_lock_init (gl_recursive_lock_t *lock)
+{
+  pthread_mutexattr_t attributes;
+
+  if (pthread_mutexattr_init (&attributes) != 0)
+    abort ();
+  if (pthread_mutexattr_settype (&attributes, PTHREAD_MUTEX_RECURSIVE) != 0)
+    abort ();
+  if (pthread_mutex_init (&lock->recmutex, &attributes) != 0)
+    abort ();
+  if (pthread_mutexattr_destroy (&attributes) != 0)
+    abort ();
+  lock->initialized = 1;
+}
+
+void
+glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+{
+  if (!lock->initialized)
+    {
+      if (pthread_mutex_lock (&lock->guard) != 0)
+       abort ();
+      if (!lock->initialized)
+       glthread_recursive_lock_init (lock);
+      if (pthread_mutex_unlock (&lock->guard) != 0)
+       abort ();
+    }
+  if (pthread_mutex_lock (&lock->recmutex) != 0)
+    abort ();
+}
+
+void
+glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+{
+  if (!lock->initialized)
+    abort ();
+  if (pthread_mutex_unlock (&lock->recmutex) != 0)
+    abort ();
+}
+
+void
+glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+{
+  if (!lock->initialized)
+    abort ();
+  if (pthread_mutex_destroy (&lock->recmutex) != 0)
+    abort ();
+  lock->initialized = 0;
+}
+
+#  endif
+
+# else
+
+void
+glthread_recursive_lock_init (gl_recursive_lock_t *lock)
+{
+  if (pthread_mutex_init (&lock->mutex, NULL) != 0)
+    abort ();
+  lock->owner = (pthread_t) 0;
+  lock->depth = 0;
+}
+
+void
+glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+{
+  pthread_t self = pthread_self ();
+  if (lock->owner != self)
+    {
+      if (pthread_mutex_lock (&lock->mutex) != 0)
+       abort ();
+      lock->owner = self;
+    }
+  if (++(lock->depth) == 0) /* wraparound? */
+    abort ();
+}
+
+void
+glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != pthread_self ())
+    abort ();
+  if (lock->depth == 0)
+    abort ();
+  if (--(lock->depth) == 0)
+    {
+      lock->owner = (pthread_t) 0;
+      if (pthread_mutex_unlock (&lock->mutex) != 0)
+       abort ();
+    }
+}
+
+void
+glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != (pthread_t) 0)
+    abort ();
+  if (pthread_mutex_destroy (&lock->mutex) != 0)
+    abort ();
+}
+
+# endif
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+static const pthread_once_t fresh_once = PTHREAD_ONCE_INIT;
+
+int
+glthread_once_singlethreaded (pthread_once_t *once_control)
+{
+  /* We don't know whether pthread_once_t is an integer type, a floating-point
+     type, a pointer type, or a structure type.  */
+  char *firstbyte = (char *)once_control;
+  if (*firstbyte == *(const char *)&fresh_once)
+    {
+      /* First time use of once_control.  Invert the first byte.  */
+      *firstbyte = ~ *(const char *)&fresh_once;
+      return 1;
+    }
+  else
+    return 0;
+}
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_PTH_THREADS
+
+/* Use the GNU Pth threads library.  */
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+void
+glthread_once_call (void *arg)
+{
+  void (**gl_once_temp_addr) (void) = (void (**) (void)) arg;
+  void (*initfunction) (void) = *gl_once_temp_addr;
+  initfunction ();
+}
+
+int
+glthread_once_singlethreaded (pth_once_t *once_control)
+{
+  /* We know that pth_once_t is an integer type.  */
+  if (*once_control == PTH_ONCE_INIT)
+    {
+      /* First time use of once_control.  Invert the marker.  */
+      *once_control = ~ PTH_ONCE_INIT;
+      return 1;
+    }
+  else
+    return 0;
+}
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_SOLARIS_THREADS
+
+/* Use the old Solaris threads library.  */
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+void
+glthread_recursive_lock_init (gl_recursive_lock_t *lock)
+{
+  if (mutex_init (&lock->mutex, USYNC_THREAD, NULL) != 0)
+    abort ();
+  lock->owner = (thread_t) 0;
+  lock->depth = 0;
+}
+
+void
+glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+{
+  thread_t self = thr_self ();
+  if (lock->owner != self)
+    {
+      if (mutex_lock (&lock->mutex) != 0)
+       abort ();
+      lock->owner = self;
+    }
+  if (++(lock->depth) == 0) /* wraparound? */
+    abort ();
+}
+
+void
+glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != thr_self ())
+    abort ();
+  if (lock->depth == 0)
+    abort ();
+  if (--(lock->depth) == 0)
+    {
+      lock->owner = (thread_t) 0;
+      if (mutex_unlock (&lock->mutex) != 0)
+       abort ();
+    }
+}
+
+void
+glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != (thread_t) 0)
+    abort ();
+  if (mutex_destroy (&lock->mutex) != 0)
+    abort ();
+}
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+void
+glthread_once (gl_once_t *once_control, void (*initfunction) (void))
+{
+  if (!once_control->inited)
+    {
+      /* Use the mutex to guarantee that if another thread is already calling
+        the initfunction, this thread waits until it's finished.  */
+      if (mutex_lock (&once_control->mutex) != 0)
+       abort ();
+      if (!once_control->inited)
+       {
+         once_control->inited = 1;
+         initfunction ();
+       }
+      if (mutex_unlock (&once_control->mutex) != 0)
+       abort ();
+    }
+}
+
+int
+glthread_once_singlethreaded (gl_once_t *once_control)
+{
+  /* We know that gl_once_t contains an integer type.  */
+  if (!once_control->inited)
+    {
+      /* First time use of once_control.  Invert the marker.  */
+      once_control->inited = ~ 0;
+      return 1;
+    }
+  else
+    return 0;
+}
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_WIN32_THREADS
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+void
+glthread_lock_init (gl_lock_t *lock)
+{
+  InitializeCriticalSection (&lock->lock);
+  lock->guard.done = 1;
+}
+
+void
+glthread_lock_lock (gl_lock_t *lock)
+{
+  if (!lock->guard.done)
+    {
+      if (InterlockedIncrement (&lock->guard.started) == 0)
+       /* This thread is the first one to need this lock.  Initialize it.  */
+       glthread_lock_init (lock);
+      else
+       /* Yield the CPU while waiting for another thread to finish
+          initializing this lock.  */
+       while (!lock->guard.done)
+         Sleep (0);
+    }
+  EnterCriticalSection (&lock->lock);
+}
+
+void
+glthread_lock_unlock (gl_lock_t *lock)
+{
+  if (!lock->guard.done)
+    abort ();
+  LeaveCriticalSection (&lock->lock);
+}
+
+void
+glthread_lock_destroy (gl_lock_t *lock)
+{
+  if (!lock->guard.done)
+    abort ();
+  DeleteCriticalSection (&lock->lock);
+  lock->guard.done = 0;
+}
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+static inline void
+gl_waitqueue_init (gl_waitqueue_t *wq)
+{
+  wq->array = NULL;
+  wq->count = 0;
+  wq->alloc = 0;
+  wq->offset = 0;
+}
+
+/* Enqueues the current thread, represented by an event, in a wait queue.
+   Returns INVALID_HANDLE_VALUE if an allocation failure occurs.  */
+static HANDLE
+gl_waitqueue_add (gl_waitqueue_t *wq)
+{
+  HANDLE event;
+  unsigned int index;
+
+  if (wq->count == wq->alloc)
+    {
+      unsigned int new_alloc = 2 * wq->alloc + 1;
+      HANDLE *new_array =
+       (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
+      if (new_array == NULL)
+       /* No more memory.  */
+       return INVALID_HANDLE_VALUE;
+      /* Now is a good opportunity to rotate the array so that its contents
+        starts at offset 0.  */
+      if (wq->offset > 0)
+       {
+         unsigned int old_count = wq->count;
+         unsigned int old_alloc = wq->alloc;
+         unsigned int old_offset = wq->offset;
+         unsigned int i;
+         if (old_offset + old_count > old_alloc)
+           {
+             unsigned int limit = old_offset + old_count - old_alloc;
+             for (i = 0; i < limit; i++)
+               new_array[old_alloc + i] = new_array[i];
+           }
+         for (i = 0; i < old_count; i++)
+           new_array[i] = new_array[old_offset + i];
+         wq->offset = 0;
+       }
+      wq->array = new_array;
+      wq->alloc = new_alloc;
+    }
+  event = CreateEvent (NULL, TRUE, FALSE, NULL);
+  if (event == INVALID_HANDLE_VALUE)
+    /* No way to allocate an event.  */
+    return INVALID_HANDLE_VALUE;
+  index = wq->offset + wq->count;
+  if (index >= wq->alloc)
+    index -= wq->alloc;
+  wq->array[index] = event;
+  wq->count++;
+  return event;
+}
+
+/* Notifies the first thread from a wait queue and dequeues it.  */
+static inline void
+gl_waitqueue_notify_first (gl_waitqueue_t *wq)
+{
+  SetEvent (wq->array[wq->offset + 0]);
+  wq->offset++;
+  wq->count--;
+  if (wq->count == 0 || wq->offset == wq->alloc)
+    wq->offset = 0;
+}
+
+/* Notifies all threads from a wait queue and dequeues them all.  */
+static inline void
+gl_waitqueue_notify_all (gl_waitqueue_t *wq)
+{
+  unsigned int i;
+
+  for (i = 0; i < wq->count; i++)
+    {
+      unsigned int index = wq->offset + i;
+      if (index >= wq->alloc)
+       index -= wq->alloc;
+      SetEvent (wq->array[index]);
+    }
+  wq->count = 0;
+  wq->offset = 0;
+}
+
+void
+glthread_rwlock_init (gl_rwlock_t *lock)
+{
+  InitializeCriticalSection (&lock->lock);
+  gl_waitqueue_init (&lock->waiting_readers);
+  gl_waitqueue_init (&lock->waiting_writers);
+  lock->runcount = 0;
+  lock->guard.done = 1;
+}
+
+void
+glthread_rwlock_rdlock (gl_rwlock_t *lock)
+{
+  if (!lock->guard.done)
+    {
+      if (InterlockedIncrement (&lock->guard.started) == 0)
+       /* This thread is the first one to need this lock.  Initialize it.  */
+       glthread_rwlock_init (lock);
+      else
+       /* Yield the CPU while waiting for another thread to finish
+          initializing this lock.  */
+       while (!lock->guard.done)
+         Sleep (0);
+    }
+  EnterCriticalSection (&lock->lock);
+  /* Test whether only readers are currently running, and whether the runcount
+     field will not overflow.  */
+  if (!(lock->runcount + 1 > 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+        waiting_readers.  */
+      HANDLE event = gl_waitqueue_add (&lock->waiting_readers);
+      if (event != INVALID_HANDLE_VALUE)
+       {
+         DWORD result;
+         LeaveCriticalSection (&lock->lock);
+         /* Wait until another thread signals this event.  */
+         result = WaitForSingleObject (event, INFINITE);
+         if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+           abort ();
+         CloseHandle (event);
+         /* The thread which signalled the event already did the bookkeeping:
+            removed us from the waiting_readers, incremented lock->runcount.  */
+         if (!(lock->runcount > 0))
+           abort ();
+         return;
+       }
+      else
+       {
+         /* Allocation failure.  Weird.  */
+         do
+           {
+             LeaveCriticalSection (&lock->lock);
+             Sleep (1);
+             EnterCriticalSection (&lock->lock);
+           }
+         while (!(lock->runcount + 1 > 0));
+       }
+    }
+  lock->runcount++;
+  LeaveCriticalSection (&lock->lock);
+}
+
+void
+glthread_rwlock_wrlock (gl_rwlock_t *lock)
+{
+  if (!lock->guard.done)
+    {
+      if (InterlockedIncrement (&lock->guard.started) == 0)
+       /* This thread is the first one to need this lock.  Initialize it.  */
+       glthread_rwlock_init (lock);
+      else
+       /* Yield the CPU while waiting for another thread to finish
+          initializing this lock.  */
+       while (!lock->guard.done)
+         Sleep (0);
+    }
+  EnterCriticalSection (&lock->lock);
+  /* Test whether no readers or writers are currently running.  */
+  if (!(lock->runcount == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+        waiting_writers.  */
+      HANDLE event = gl_waitqueue_add (&lock->waiting_writers);
+      if (event != INVALID_HANDLE_VALUE)
+       {
+         DWORD result;
+         LeaveCriticalSection (&lock->lock);
+         /* Wait until another thread signals this event.  */
+         result = WaitForSingleObject (event, INFINITE);
+         if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+           abort ();
+         CloseHandle (event);
+         /* The thread which signalled the event already did the bookkeeping:
+            removed us from the waiting_writers, set lock->runcount = -1.  */
+         if (!(lock->runcount == -1))
+           abort ();
+         return;
+       }
+      else
+       {
+         /* Allocation failure.  Weird.  */
+         do
+           {
+             LeaveCriticalSection (&lock->lock);
+             Sleep (1);
+             EnterCriticalSection (&lock->lock);
+           }
+         while (!(lock->runcount == 0));
+       }
+    }
+  lock->runcount--; /* runcount becomes -1 */
+  LeaveCriticalSection (&lock->lock);
+}
+
+void
+glthread_rwlock_unlock (gl_rwlock_t *lock)
+{
+  if (!lock->guard.done)
+    abort ();
+  EnterCriticalSection (&lock->lock);
+  if (lock->runcount < 0)
+    {
+      /* Drop a writer lock.  */
+      if (!(lock->runcount == -1))
+       abort ();
+      lock->runcount = 0;
+    }
+  else
+    {
+      /* Drop a reader lock.  */
+      if (!(lock->runcount > 0))
+       abort ();
+      lock->runcount--;
+    }
+  if (lock->runcount == 0)
+    {
+      /* POSIX recommends that "write locks shall take precedence over read
+        locks", to avoid "writer starvation".  */
+      if (lock->waiting_writers.count > 0)
+       {
+         /* Wake up one of the waiting writers.  */
+         lock->runcount--;
+         gl_waitqueue_notify_first (&lock->waiting_writers);
+       }
+      else
+       {
+         /* Wake up all waiting readers.  */
+         lock->runcount += lock->waiting_readers.count;
+         gl_waitqueue_notify_all (&lock->waiting_readers);
+       }
+    }
+  LeaveCriticalSection (&lock->lock);
+}
+
+void
+glthread_rwlock_destroy (gl_rwlock_t *lock)
+{
+  if (!lock->guard.done)
+    abort ();
+  if (lock->runcount != 0)
+    abort ();
+  DeleteCriticalSection (&lock->lock);
+  if (lock->waiting_readers.array != NULL)
+    free (lock->waiting_readers.array);
+  if (lock->waiting_writers.array != NULL)
+    free (lock->waiting_writers.array);
+  lock->guard.done = 0;
+}
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+void
+glthread_recursive_lock_init (gl_recursive_lock_t *lock)
+{
+  lock->owner = 0;
+  lock->depth = 0;
+  InitializeCriticalSection (&lock->lock);
+  lock->guard.done = 1;
+}
+
+void
+glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+{
+  if (!lock->guard.done)
+    {
+      if (InterlockedIncrement (&lock->guard.started) == 0)
+       /* This thread is the first one to need this lock.  Initialize it.  */
+       glthread_recursive_lock_init (lock);
+      else
+       /* Yield the CPU while waiting for another thread to finish
+          initializing this lock.  */
+       while (!lock->guard.done)
+         Sleep (0);
+    }
+  {
+    DWORD self = GetCurrentThreadId ();
+    if (lock->owner != self)
+      {
+       EnterCriticalSection (&lock->lock);
+       lock->owner = self;
+      }
+    if (++(lock->depth) == 0) /* wraparound? */
+      abort ();
+  }
+}
+
+void
+glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != GetCurrentThreadId ())
+    abort ();
+  if (lock->depth == 0)
+    abort ();
+  if (--(lock->depth) == 0)
+    {
+      lock->owner = 0;
+      LeaveCriticalSection (&lock->lock);
+    }
+}
+
+void
+glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+{
+  if (lock->owner != 0)
+    abort ();
+  DeleteCriticalSection (&lock->lock);
+  lock->guard.done = 0;
+}
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+void
+glthread_once (gl_once_t *once_control, void (*initfunction) (void))
+{
+  if (once_control->inited <= 0)
+    {
+      if (InterlockedIncrement (&once_control->started) == 0)
+       {
+         /* This thread is the first one to come to this once_control.  */
+         InitializeCriticalSection (&once_control->lock);
+         EnterCriticalSection (&once_control->lock);
+         once_control->inited = 0;
+         initfunction ();
+         once_control->inited = 1;
+         LeaveCriticalSection (&once_control->lock);
+       }
+      else
+       {
+         /* Undo last operation.  */
+         InterlockedDecrement (&once_control->started);
+         /* Some other thread has already started the initialization.
+            Yield the CPU while waiting for the other thread to finish
+            initializing and taking the lock.  */
+         while (once_control->inited < 0)
+           Sleep (0);
+         if (once_control->inited <= 0)
+           {
+             /* Take the lock.  This blocks until the other thread has
+                finished calling the initfunction.  */
+             EnterCriticalSection (&once_control->lock);
+             LeaveCriticalSection (&once_control->lock);
+             if (!(once_control->inited > 0))
+               abort ();
+           }
+       }
+    }
+}
+
+#endif
+
+/* ========================================================================= */
diff --git a/gettext-tools/lib/lock.h b/gettext-tools/lib/lock.h
new file mode 100644 (file)
index 0000000..be99139
--- /dev/null
@@ -0,0 +1,801 @@
+/* Locking in multithreaded situations.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU Library General Public License as published
+   by the Free Software Foundation; either version 2, 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+   USA.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+   Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.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);
+
+   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);
+
+   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);
+
+  Once-only execution:
+     Type:                gl_once_t
+     Initializer:         gl_once_define(extern, name)
+     Execution:           gl_once (name, initfunction);
+*/
+
+
+#ifndef _LOCK_H
+#define _LOCK_H
+
+/* ========================================================================= */
+
+#if USE_POSIX_THREADS
+
+/* Use the POSIX threads library.  */
+
+# include <pthread.h>
+# include <stdlib.h>
+
+# 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
+#  ifndef pthread_self
+#   pragma weak pthread_self
+#  endif
+
+#  if !PTHREAD_IN_USE_DETECTION_HARD
+#   pragma weak pthread_cancel
+#   define pthread_in_use() (pthread_cancel != NULL)
+#  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 gl_lock_init(NAME) \
+    if (pthread_in_use () && pthread_mutex_init (&NAME, NULL) != 0) abort ()
+# define gl_lock_lock(NAME) \
+    if (pthread_in_use () && pthread_mutex_lock (&NAME) != 0) abort ()
+# define gl_lock_unlock(NAME) \
+    if (pthread_in_use () && pthread_mutex_unlock (&NAME) != 0) abort ()
+# define gl_lock_destroy(NAME) \
+    if (pthread_in_use () && pthread_mutex_destroy (&NAME) != 0) abort ()
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+# if HAVE_PTHREAD_RWLOCK
+
+#  ifdef PTHREAD_RWLOCK_INITIALIZER
+
+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;
+#   define gl_rwlock_initializer \
+      PTHREAD_RWLOCK_INITIALIZER
+#   define gl_rwlock_init(NAME) \
+      if (pthread_in_use () && pthread_rwlock_init (&NAME, NULL) != 0) abort ()
+#   define gl_rwlock_rdlock(NAME) \
+      if (pthread_in_use () && pthread_rwlock_rdlock (&NAME) != 0) abort ()
+#   define gl_rwlock_wrlock(NAME) \
+      if (pthread_in_use () && pthread_rwlock_wrlock (&NAME) != 0) abort ()
+#   define gl_rwlock_unlock(NAME) \
+      if (pthread_in_use () && pthread_rwlock_unlock (&NAME) != 0) abort ()
+#   define gl_rwlock_destroy(NAME) \
+      if (pthread_in_use () && pthread_rwlock_destroy (&NAME) != 0) abort ()
+
+#  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 gl_rwlock_init(NAME) \
+      if (pthread_in_use ()) glthread_rwlock_init (&NAME)
+#   define gl_rwlock_rdlock(NAME) \
+      if (pthread_in_use ()) glthread_rwlock_rdlock (&NAME)
+#   define gl_rwlock_wrlock(NAME) \
+      if (pthread_in_use ()) glthread_rwlock_wrlock (&NAME)
+#   define gl_rwlock_unlock(NAME) \
+      if (pthread_in_use ()) glthread_rwlock_unlock (&NAME)
+#   define gl_rwlock_destroy(NAME) \
+      if (pthread_in_use ()) glthread_rwlock_destroy (&NAME)
+extern void glthread_rwlock_init (gl_rwlock_t *lock);
+extern void glthread_rwlock_rdlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_wrlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_unlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_destroy (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 gl_rwlock_init(NAME) \
+    if (pthread_in_use ()) glthread_rwlock_init (&NAME)
+# define gl_rwlock_rdlock(NAME) \
+    if (pthread_in_use ()) glthread_rwlock_rdlock (&NAME)
+# define gl_rwlock_wrlock(NAME) \
+    if (pthread_in_use ()) glthread_rwlock_wrlock (&NAME)
+# define gl_rwlock_unlock(NAME) \
+    if (pthread_in_use ()) glthread_rwlock_unlock (&NAME)
+# define gl_rwlock_destroy(NAME) \
+    if (pthread_in_use ()) glthread_rwlock_destroy (&NAME)
+extern void glthread_rwlock_init (gl_rwlock_t *lock);
+extern void glthread_rwlock_rdlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_wrlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_unlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_destroy (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 gl_recursive_lock_init(NAME) \
+      if (pthread_in_use () && pthread_mutex_init (&NAME, NULL) != 0) abort ()
+#   define gl_recursive_lock_lock(NAME) \
+      if (pthread_in_use () && pthread_mutex_lock (&NAME) != 0) abort ()
+#   define gl_recursive_lock_unlock(NAME) \
+      if (pthread_in_use () && pthread_mutex_unlock (&NAME) != 0) abort ()
+#   define gl_recursive_lock_destroy(NAME) \
+      if (pthread_in_use () && pthread_mutex_destroy (&NAME) != 0) abort ()
+
+#  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 gl_recursive_lock_init(NAME) \
+      if (pthread_in_use ()) glthread_recursive_lock_init (&NAME)
+#   define gl_recursive_lock_lock(NAME) \
+      if (pthread_in_use ()) glthread_recursive_lock_lock (&NAME)
+#   define gl_recursive_lock_unlock(NAME) \
+      if (pthread_in_use ()) glthread_recursive_lock_unlock (&NAME)
+#   define gl_recursive_lock_destroy(NAME) \
+      if (pthread_in_use ()) glthread_recursive_lock_destroy (&NAME)
+extern void glthread_recursive_lock_init (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_lock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_unlock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_destroy (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 gl_recursive_lock_init(NAME) \
+     if (pthread_in_use ()) glthread_recursive_lock_init (&NAME)
+#  define gl_recursive_lock_lock(NAME) \
+     if (pthread_in_use ()) glthread_recursive_lock_lock (&NAME)
+#  define gl_recursive_lock_unlock(NAME) \
+     if (pthread_in_use ()) glthread_recursive_lock_unlock (&NAME)
+#  define gl_recursive_lock_destroy(NAME) \
+     if (pthread_in_use ()) glthread_recursive_lock_destroy (&NAME)
+extern void glthread_recursive_lock_init (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_lock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_unlock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_destroy (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;
+# define gl_once(NAME, INITFUNCTION) \
+    do                                                   \
+      {                                                  \
+        if (pthread_in_use ())                           \
+          {                                              \
+            if (pthread_once (&NAME, INITFUNCTION) != 0) \
+              abort ();                                  \
+          }                                              \
+        else                                             \
+          {                                              \
+            if (glthread_once_singlethreaded (&NAME))    \
+              INITFUNCTION ();                           \
+          }                                              \
+      }                                                  \
+    while (0)
+extern int glthread_once_singlethreaded (pthread_once_t *once_control);
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_PTH_THREADS
+
+/* Use the GNU Pth threads library.  */
+
+# include <pth.h>
+# include <stdlib.h>
+
+# if USE_PTH_THREADS_WEAK
+
+/* Use weak references to the GNU Pth threads library.  */
+
+#  pragma weak pth_mutex_init
+#  pragma weak pth_mutex_acquire
+#  pragma weak pth_mutex_release
+#  pragma weak pth_rwlock_init
+#  pragma weak pth_rwlock_acquire
+#  pragma weak pth_rwlock_release
+#  pragma weak pth_once
+
+#  pragma weak pth_cancel
+#  define pth_in_use() (pth_cancel != NULL)
+
+# else
+
+#  define pth_in_use() 1
+
+# endif
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef pth_mutex_t gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME) \
+    STORAGECLASS pth_mutex_t NAME;
+# define gl_lock_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS pth_mutex_t NAME = gl_lock_initializer;
+# define gl_lock_initializer \
+    PTH_MUTEX_INIT
+# define gl_lock_init(NAME) \
+    if (pth_in_use() && !pth_mutex_init (&NAME)) abort ()
+# define gl_lock_lock(NAME) \
+    if (pth_in_use() && !pth_mutex_acquire (&NAME, 0, NULL)) abort ()
+# define gl_lock_unlock(NAME) \
+    if (pth_in_use() && !pth_mutex_release (&NAME)) abort ()
+# define gl_lock_destroy(NAME) \
+    (void)(&NAME)
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef pth_rwlock_t gl_rwlock_t;
+#  define gl_rwlock_define(STORAGECLASS, NAME) \
+     STORAGECLASS pth_rwlock_t NAME;
+#  define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+     STORAGECLASS pth_rwlock_t NAME = gl_rwlock_initializer;
+#  define gl_rwlock_initializer \
+     PTH_RWLOCK_INIT
+#  define gl_rwlock_init(NAME) \
+     if (pth_in_use() && !pth_rwlock_init (&NAME)) abort ()
+#  define gl_rwlock_rdlock(NAME) \
+     if (pth_in_use() && !pth_rwlock_acquire (&NAME, PTH_RWLOCK_RD, 0, NULL)) abort ()
+#  define gl_rwlock_wrlock(NAME) \
+     if (pth_in_use() && !pth_rwlock_acquire (&NAME, PTH_RWLOCK_RW, 0, NULL)) abort ()
+#  define gl_rwlock_unlock(NAME) \
+     if (pth_in_use() && !pth_rwlock_release (&NAME)) abort ()
+#  define gl_rwlock_destroy(NAME) \
+     (void)(&NAME)
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+/* In Pth, mutexes are recursive by default.  */
+typedef pth_mutex_t gl_recursive_lock_t;
+#  define gl_recursive_lock_define(STORAGECLASS, NAME) \
+     STORAGECLASS pth_mutex_t NAME;
+#  define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
+     STORAGECLASS pth_mutex_t NAME = gl_recursive_lock_initializer;
+#  define gl_recursive_lock_initializer \
+     PTH_MUTEX_INIT
+#  define gl_recursive_lock_init(NAME) \
+     if (pth_in_use() && !pth_mutex_init (&NAME)) abort ()
+#  define gl_recursive_lock_lock(NAME) \
+     if (pth_in_use() && !pth_mutex_acquire (&NAME, 0, NULL)) abort ()
+#  define gl_recursive_lock_unlock(NAME) \
+     if (pth_in_use() && !pth_mutex_release (&NAME)) abort ()
+#  define gl_recursive_lock_destroy(NAME) \
+     (void)(&NAME)
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef pth_once_t gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+    STORAGECLASS pth_once_t NAME = PTH_ONCE_INIT;
+# define gl_once(NAME, INITFUNCTION) \
+    do                                                                \
+      {                                                               \
+        if (pth_in_use ())                                            \
+          {                                                           \
+            void (*gl_once_temp) (void) = INITFUNCTION;               \
+            if (!pth_once (&NAME, glthread_once_call, &gl_once_temp)) \
+              abort ();                                               \
+          }                                                           \
+        else                                                          \
+          {                                                           \
+            if (glthread_once_singlethreaded (&NAME))                 \
+              INITFUNCTION ();                                        \
+          }                                                           \
+      }                                                               \
+    while (0)
+extern void glthread_once_call (void *arg);
+extern int glthread_once_singlethreaded (pth_once_t *once_control);
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_SOLARIS_THREADS
+
+/* Use the old Solaris threads library.  */
+
+# include <thread.h>
+# include <synch.h>
+# include <stdlib.h>
+
+# if USE_SOLARIS_THREADS_WEAK
+
+/* Use weak references to the old Solaris threads library.  */
+
+#  pragma weak mutex_init
+#  pragma weak mutex_lock
+#  pragma weak mutex_unlock
+#  pragma weak mutex_destroy
+#  pragma weak rwlock_init
+#  pragma weak rw_rdlock
+#  pragma weak rw_wrlock
+#  pragma weak rw_unlock
+#  pragma weak rwlock_destroy
+#  pragma weak thr_self
+
+#  pragma weak thr_suspend
+#  define thread_in_use() (thr_suspend != NULL)
+
+# else
+
+#  define thread_in_use() 1
+
+# endif
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef mutex_t gl_lock_t;
+# define gl_lock_define(STORAGECLASS, NAME) \
+    STORAGECLASS mutex_t NAME;
+# define gl_lock_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS mutex_t NAME = gl_lock_initializer;
+# define gl_lock_initializer \
+    DEFAULTMUTEX
+# define gl_lock_init(NAME) \
+    if (thread_in_use () && mutex_init (&NAME, USYNC_THREAD, NULL) != 0) abort ()
+# define gl_lock_lock(NAME) \
+    if (thread_in_use () && mutex_lock (&NAME) != 0) abort ()
+# define gl_lock_unlock(NAME) \
+    if (thread_in_use () && mutex_unlock (&NAME) != 0) abort ()
+# define gl_lock_destroy(NAME) \
+    if (thread_in_use () && mutex_destroy (&NAME) != 0) abort ()
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef rwlock_t gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME) \
+    STORAGECLASS rwlock_t NAME;
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS rwlock_t NAME = gl_rwlock_initializer;
+# define gl_rwlock_initializer \
+    DEFAULTRWLOCK
+# define gl_rwlock_init(NAME) \
+    if (thread_in_use () && rwlock_init (&NAME, USYNC_THREAD, NULL) != 0) abort ()
+# define gl_rwlock_rdlock(NAME) \
+    if (thread_in_use () && rw_rdlock (&NAME) != 0) abort ()
+# define gl_rwlock_wrlock(NAME) \
+    if (thread_in_use () && rw_wrlock (&NAME) != 0) abort ()
+# define gl_rwlock_unlock(NAME) \
+    if (thread_in_use () && rw_unlock (&NAME) != 0) abort ()
+# define gl_rwlock_destroy(NAME) \
+    if (thread_in_use () && rwlock_destroy (&NAME) != 0) abort ()
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+/* Old Solaris threads did not have recursive locks.
+   We have to implement them ourselves.  */
+
+typedef struct
+        {
+          mutex_t mutex;
+          thread_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 \
+    { DEFAULTMUTEX, (thread_t) 0, 0 }
+# define gl_recursive_lock_init(NAME) \
+    if (thread_in_use ()) glthread_recursive_lock_init (&NAME)
+# define gl_recursive_lock_lock(NAME) \
+    if (thread_in_use ()) glthread_recursive_lock_lock (&NAME)
+# define gl_recursive_lock_unlock(NAME) \
+    if (thread_in_use ()) glthread_recursive_lock_unlock (&NAME)
+# define gl_recursive_lock_destroy(NAME) \
+    if (thread_in_use ()) glthread_recursive_lock_destroy (&NAME)
+extern void glthread_recursive_lock_init (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_lock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_unlock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_destroy (gl_recursive_lock_t *lock);
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef struct
+        {
+          volatile int inited;
+          mutex_t mutex;
+        }
+        gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+    STORAGECLASS gl_once_t NAME = { 0, DEFAULTMUTEX };
+# define gl_once(NAME, INITFUNCTION) \
+    do                                                \
+      {                                               \
+        if (thread_in_use ())                         \
+          {                                           \
+            glthread_once (&NAME, INITFUNCTION);      \
+          }                                           \
+        else                                          \
+          {                                           \
+            if (glthread_once_singlethreaded (&NAME)) \
+              INITFUNCTION ();                        \
+          }                                           \
+      }                                               \
+    while (0)
+extern void glthread_once (gl_once_t *once_control, void (*initfunction) (void));
+extern int glthread_once_singlethreaded (gl_once_t *once_control);
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_WIN32_THREADS
+
+# include <windows.h>
+
+/* We can use CRITICAL_SECTION directly, rather than the Win32 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.  */
+
+typedef struct { volatile int done; volatile long started; } gl_spinlock_t;
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+typedef struct
+        {
+          gl_spinlock_t guard; /* protects the initialization */
+          CRITICAL_SECTION lock;
+        }
+        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 \
+    { { 0, -1 } }
+# define gl_lock_init(NAME) \
+    glthread_lock_init (&NAME)
+# define gl_lock_lock(NAME) \
+    glthread_lock_lock (&NAME)
+# define gl_lock_unlock(NAME) \
+    glthread_lock_unlock (&NAME)
+# define gl_lock_destroy(NAME) \
+    glthread_lock_destroy (&NAME)
+extern void glthread_lock_init (gl_lock_t *lock);
+extern void glthread_lock_lock (gl_lock_t *lock);
+extern void glthread_lock_unlock (gl_lock_t *lock);
+extern void glthread_lock_destroy (gl_lock_t *lock);
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+/* It is impossible to implement read-write locks using plain locks, without
+   introducing an extra thread dedicated to managing read-write locks.
+   Therefore here we need to use the low-level Event type.  */
+
+typedef struct
+        {
+          HANDLE *array; /* array of waiting threads, each represented by an event */
+          unsigned int count; /* number of waiting threads */
+          unsigned int alloc; /* length of allocated array */
+          unsigned int offset; /* index of first waiting thread in array */
+        }
+        gl_waitqueue_t;
+typedef struct
+        {
+          gl_spinlock_t guard; /* protects the initialization */
+          CRITICAL_SECTION lock; /* protects the remaining fields */
+          gl_waitqueue_t waiting_readers; /* waiting readers */
+          gl_waitqueue_t waiting_writers; /* 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 \
+    { { 0, -1 } }
+# define gl_rwlock_init(NAME) \
+    glthread_rwlock_init (&NAME)
+# define gl_rwlock_rdlock(NAME) \
+    glthread_rwlock_rdlock (&NAME)
+# define gl_rwlock_wrlock(NAME) \
+    glthread_rwlock_wrlock (&NAME)
+# define gl_rwlock_unlock(NAME) \
+    glthread_rwlock_unlock (&NAME)
+# define gl_rwlock_destroy(NAME) \
+    glthread_rwlock_destroy (&NAME)
+extern void glthread_rwlock_init (gl_rwlock_t *lock);
+extern void glthread_rwlock_rdlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_wrlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_unlock (gl_rwlock_t *lock);
+extern void glthread_rwlock_destroy (gl_rwlock_t *lock);
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+/* The Win32 documentation says that CRITICAL_SECTION already implements a
+   recursive lock.  But we need not rely on it: It's easy to implement a
+   recursive lock without this assumption.  */
+
+typedef struct
+        {
+          gl_spinlock_t guard; /* protects the initialization */
+          DWORD owner;
+          unsigned long depth;
+          CRITICAL_SECTION lock;
+        }
+        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 \
+    { { 0, -1 }, 0, 0 }
+# define gl_recursive_lock_init(NAME) \
+    glthread_recursive_lock_init (&NAME)
+# define gl_recursive_lock_lock(NAME) \
+    glthread_recursive_lock_lock (&NAME)
+# define gl_recursive_lock_unlock(NAME) \
+    glthread_recursive_lock_unlock (&NAME)
+# define gl_recursive_lock_destroy(NAME) \
+    glthread_recursive_lock_destroy (&NAME)
+extern void glthread_recursive_lock_init (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_lock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_unlock (gl_recursive_lock_t *lock);
+extern void glthread_recursive_lock_destroy (gl_recursive_lock_t *lock);
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef struct
+        {
+          volatile int inited;
+          volatile long started;
+          CRITICAL_SECTION lock;
+        }
+        gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+    STORAGECLASS gl_once_t NAME = { -1, -1 };
+# define gl_once(NAME, INITFUNCTION) \
+    glthread_once (&NAME, INITFUNCTION)
+extern void glthread_once (gl_once_t *once_control, void (*initfunction) (void));
+
+#endif
+
+/* ========================================================================= */
+
+#if !(USE_POSIX_THREADS || USE_PTH_THREADS || USE_SOLARIS_THREADS || USE_WIN32_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 gl_lock_init(NAME)
+# define gl_lock_lock(NAME)
+# define gl_lock_unlock(NAME)
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+typedef int gl_rwlock_t;
+# define gl_rwlock_define(STORAGECLASS, NAME)
+# define gl_rwlock_define_initialized(STORAGECLASS, NAME)
+# define gl_rwlock_init(NAME)
+# define gl_rwlock_rdlock(NAME)
+# define gl_rwlock_wrlock(NAME)
+# define gl_rwlock_unlock(NAME)
+
+/* --------------------- 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 gl_recursive_lock_init(NAME)
+# define gl_recursive_lock_lock(NAME)
+# define gl_recursive_lock_unlock(NAME)
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+typedef int gl_once_t;
+# define gl_once_define(STORAGECLASS, NAME) \
+    STORAGECLASS gl_once_t NAME = 0;
+# define gl_once(NAME, INITFUNCTION) \
+    do                       \
+      {                      \
+        if (NAME == 0)       \
+          {                  \
+            NAME = ~ 0;      \
+            INITFUNCTION (); \
+          }                  \
+      }                      \
+    while (0)
+
+#endif
+
+/* ========================================================================= */
+
+#endif /* _LOCK_H */