--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2008-08-17  Yoann Vandoorselaere  <yoann.v@prelude-ids.com>
+
+	New module 'cond'.
+	* modules/cond: New file.
+	* lib/glthread/cond.h: New file.
+	* lib/glthread/cond.c: New file.
+	* m4/cond.m4: New file.
+
 2008-08-16  Eric Blake  <ebb9@byu.net>
 
 	c-stack: fix regression on Irix 5.3 from 2008-06-21

new file mode 100644
--- /dev/null
+++ b/lib/glthread/cond.c
@@ -0,0 +1,52 @@
+/* Condition variables for multithreading.
+   Copyright (C) 2008 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 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 General Public License for more details.
+
+   You should have received a copy of the GNU 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 Yoann Vandoorselaere <yoann@prelude-ids.org>, 2008.  */
+
+#include <config.h>
+
+#include "glthread/cond.h"
+
+/* ========================================================================= */
+
+#if USE_PTH_THREADS
+
+/* -------------------------- gl_cond_t datatype -------------------------- */
+
+int
+glthread_cond_timedwait_multithreaded (gl_cond_t *cond,
+				       gl_lock_t *lock,
+				       struct timespec *abstime)
+{
+  int ret, status;
+  pth_event_t ev;
+
+  ev = pth_event (PTH_EVENT_TIME, pth_time (abstime->tv_sec, abstime->tv_nsec / 1000));
+  ret = pth_cond_await (cond, lock, ev);
+
+  status = pth_event_status (ev);
+  pth_event_free (ev, PTH_FREE_THIS);
+
+  if (status == PTH_STATUS_OCCURRED)
+    return ETIMEDOUT;
+
+  return ret;
+}
+
+#endif
+
+/* ========================================================================= */

new file mode 100644
--- /dev/null
+++ b/lib/glthread/cond.h
@@ -0,0 +1,330 @@
+/* Condition variables for multithreading.
+   Copyright (C) 2005-2008 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 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 General Public License for more details.
+
+   You should have received a copy of the GNU 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 Yoann Vandoorselaere <yoann@prelude-ids.org>, 2008.
+   Based on Bruno Haible <bruno@clisp.org> lock.h */
+
+/*
+   Condition variables can be used for waiting until a condition
+   becomes true. In this respect, they are similar to wait queues. But
+   contrary to wait queues, condition variables have different
+   semantics that allows events to be lost when there is no thread
+   waiting for them.
+
+   Condition variable:
+     Type:                gl_cond_t
+     Declaration:         gl_cond_define(extern, name)
+     Initializer:         gl_cond_define_initialized(, name)
+     Initialization:      gl_cond_init (name);
+     Waiting:             gl_cond_wait (name, lock);
+     Timed wait:          bool timedout = gl_cond_timedwait (name, lock, abstime);
+                          where lock is a gl_lock_t variable (cf. <glthread/lock.h>)
+     Signaling:           gl_cond_signal (name);
+     Broadcasting:        gl_cond_broadcast (name);
+     De-initialization:   gl_cond_destroy (name);
+   Equivalent functions with control of error handling:
+     Initialization:      err = glthread_cond_init (&name);
+     Waiting:             err = glthread_cond_wait (&name);
+     Timed wait:          err = glthread_cond_timedwait (&name, &lock, abstime);
+     Signaling:           err = glthread_cond_signal (&name);
+     Broadcasting:        err = glthread_cond_broadcast (&name);
+     De-initialization:   err = glthread_cond_destroy (&name);
+*/
+
+
+#ifndef _GLTHREAD_COND_H
+#define _GLTHREAD_COND_H
+
+#include <errno.h>
+#include <stdbool.h>
+
+#include "glthread/lock.h"
+
+/* ========================================================================= */
+
+#if USE_POSIX_THREADS
+
+/* Use the POSIX threads library.  */
+
+# include <pthread.h>
+# include <stdlib.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_cond_init
+#  pragma weak pthread_cond_wait
+#  pragma weak pthread_cond_timedwait
+#  pragma weak pthread_cond_signal
+#  pragma weak pthread_cond_broadcast
+#  pragma weak pthread_cond_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_cond_t datatype -------------------------- */
+
+typedef pthread_cond_t gl_cond_t;
+# define gl_cond_define(STORAGECLASS, NAME) \
+    STORAGECLASS pthread_cond_t NAME;
+# define gl_cond_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS pthread_cond_t NAME = gl_cond_initializer;
+# define gl_cond_initializer \
+    PTHREAD_COND_INITIALIZER
+# define glthread_cond_init(COND) \
+    (pthread_in_use () ? pthread_cond_init (COND, NULL) : 0)
+# define glthread_cond_wait(COND, LOCK) \
+    (pthread_in_use () ? pthread_cond_wait (COND, LOCK) : 0)
+# define glthread_cond_timedwait(COND, LOCK, ABSTIME) \
+    (pthread_in_use () ? pthread_cond_timedwait (COND, LOCK, ABSTIME) : 0)
+# define glthread_cond_signal(COND) \
+    (pthread_in_use () ? pthread_cond_signal (COND) : 0)
+# define glthread_cond_broadcast(COND) \
+    (pthread_in_use () ? pthread_cond_broadcast (COND) : 0)
+# define glthread_cond_destroy(COND) \
+    (pthread_in_use () ? pthread_cond_destroy (COND) : 0)
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_PTH_THREADS
+
+/* Use the GNU Pth threads library.  */
+
+# include <pth.h>
+# include <stdlib.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+# if USE_PTH_THREADS_WEAK
+
+/* Use weak references to the GNU Pth threads library.  */
+
+#  pragma weak pth_cond_init
+#  pragma weak pth_cond_await
+#  pragma weak pth_cond_notify
+#  pragma weak pth_event
+#  pragma weak pth_timeout
+
+#  pragma weak pth_cancel
+#  define pth_in_use() (pth_cancel != NULL)
+
+# else
+
+#  define pth_in_use() 1
+
+# endif
+
+/* -------------------------- gl_cond_t datatype -------------------------- */
+
+typedef pth_cond_t gl_cond_t;
+# define gl_cond_define(STORAGECLASS, NAME) \
+    STORAGECLASS pth_cond_t NAME;
+# define gl_cond_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS pth_cond_t NAME = gl_cond_initializer;
+# define gl_cond_initializer \
+    PTH_COND_INIT
+# define glthread_cond_init(COND) \
+    (pth_in_use () && !pth_cond_init (COND) ? errno : 0)
+# define glthread_cond_wait(COND, LOCK) \
+    (pth_in_use () && !pth_cond_await (COND, LOCK, NULL) ? errno : 0)
+# define glthread_cond_timedwait(COND, LOCK, ABSTIME) \
+    (pth_in_use () ? glthread_cond_timedwait_multithreaded (COND, LOCK, ABSTIME) : 0)
+# define glthread_cond_signal(COND) \
+    (pth_in_use () && !pth_cond_notify (COND, FALSE) ? errno : 0)
+# define glthread_cond_broadcast(COND) \
+    (pth_in_use () && !pth_cond_notify (COND, TRUE) ? errno : 0)
+# define glthread_cond_destroy(COND) 0
+extern int glthread_cond_timedwait_multithreaded (gl_cond_t *cond, gl_lock_t *lock, struct timespec *abstime);
+
+#endif
+
+/* ========================================================================= */
+
+#if USE_SOLARIS_THREADS
+
+/* Use the old Solaris threads library.  */
+
+# include <thread.h>
+# include <synch.h>
+# include <stdlib.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+# if USE_SOLARIS_THREADS_WEAK
+
+/* Use weak references to the old Solaris threads library.  */
+
+#  pragma weak cond_init
+#  pragma weak cond_wait
+#  pragma weak cond_timedwait
+#  pragma weak cond_signal
+#  pragma weak cond_broadcast
+#  pragma weak cond_destroy
+#  pragma weak thr_suspend
+#  define thread_in_use() (thr_suspend != NULL)
+
+# else
+
+#  define thread_in_use() 1
+
+# endif
+
+/* -------------------------- gl_cond_t datatype -------------------------- */
+
+#define ETIMEDOUT ETIME
+
+typedef pthread_cond_t gl_cond_t;
+# define gl_cond_define(STORAGECLASS, NAME) \
+    STORAGECLASS cond_t NAME;
+# define gl_cond_define_initialized(STORAGECLASS, NAME) \
+    STORAGECLASS cond_t NAME = gl_cond_initializer;
+# define gl_cond_initializer \
+    DEFAULTCV
+# define glthread_cond_init(COND) \
+    (pthread_in_use () ? cond_init (COND, USYNC_THREAD, NULL) : 0)
+# define glthread_cond_wait(COND, LOCK) \
+    (pthread_in_use () ? cond_wait (COND, LOCK) : 0)
+# define glthread_cond_timedwait(COND, LOCK, ABSTIME) \
+    (pthread_in_use () ? cond_timedwait (COND, LOCK, ABSTIME) : 0)
+# define glthread_cond_signal(COND) \
+    (pthread_in_use () ? cond_signal (COND) : 0)
+# define glthread_cond_broadcast(COND) \
+    (pthread_in_use () ? cond_broadcast (COND) : 0)
+# define glthread_cond_destroy(COND) \
+    (pthread_in_use () ? cond_destroy (COND) : 0)
+
+#endif
+
+/* ========================================================================= */
+
+#if !(USE_POSIX_THREADS || USE_PTH_THREADS || USE_SOLARIS_THREADS || USE_WIN32_THREADS)
+
+/* Provide dummy implementation if threads are not supported.  */
+
+typedef int gl_cond_t;
+# define gl_cond_define(STORAGECLASS, NAME)
+# define gl_cond_define_initialized(STORAGECLASS, NAME)
+# define glthread_cond_init(COND) 0
+# define glthread_cond_wait(COND, LOCK) 0
+# define glthread_cond_timedwait(COND, LOCK, ABSTIME) 0
+# define glthread_cond_signal(COND) 0
+# define glthread_cond_broadcast(COND) 0
+# define glthread_cond_destroy(COND) 0
+
+#endif
+
+/* ========================================================================= */
+
+/* Macros with built-in error handling.  */
+
+#define gl_cond_init(COND)             \
+   do                                  \
+     {                                 \
+       if (glthread_cond_init (&COND)) \
+         abort ();                     \
+     }                                 \
+   while (0)
+#define gl_cond_wait(COND, LOCK)              \
+   do                                         \
+     {                                        \
+       if (glthread_cond_wait (&COND, &LOCK)) \
+         abort ();                            \
+     }                                        \
+   while (0)
+#define gl_cond_timedwait(COND, LOCK, ABSTIME) \
+  gl_cond_timedwait_func (&COND, &LOCK, ABSTIME)
+static inline bool
+gl_cond_timedwait_func (gl_cond_t *cond, gl_lock_t *lock, struct timespec *abstime)
+{
+  int err = glthread_cond_timedwait (cond, lock, abstime);
+  if (err == ETIMEDOUT)
+    return true;
+  if (err != 0)
+    abort ();
+  return false;
+}
+#define gl_cond_signal(COND)             \
+   do                                    \
+     {                                   \
+       if (glthread_cond_signal (&COND)) \
+         abort ();                       \
+     }                                   \
+   while (0)
+#define gl_cond_broadcast(COND)             \
+   do                                       \
+     {                                      \
+       if (glthread_cond_broadcast (&COND)) \
+         abort ();                          \
+     }                                      \
+   while (0)
+#define gl_cond_destroy(COND)             \
+   do                                     \
+     {                                    \
+       if (glthread_cond_destroy (&COND)) \
+         abort ();                        \
+     }                                    \
+   while (0)
+
+#endif /* _GLTHREAD_COND_H */

new file mode 100644
--- /dev/null
+++ b/m4/cond.m4
@@ -0,0 +1,11 @@
+# cond.m4 serial 1
+dnl Copyright (C) 2008 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_COND],
+[
+  AC_REQUIRE([gl_THREADLIB])
+  AC_C_INLINE
+])

new file mode 100644
--- /dev/null
+++ b/modules/cond
@@ -0,0 +1,28 @@
+Description:
+Condition variables for multithreading.
+
+Files:
+lib/glthread/cond.h
+lib/glthread/cond.c
+m4/cond.m4
+
+Depends-on:
+threadlib
+lock
+stdbool
+
+configure.ac:
+gl_COND
+
+Makefile.am:
+lib_SOURCES += glthread/cond.h glthread/cond.c
+
+Include:
+"glthread/cond.h"
+
+License:
+LGPLv2+
+
+Maintainer:
+Yoann Vandoorselaere
+