text: /* GLIB - Library of useful routines for C programming
   * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   *
   * This library 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 of the License, or (at your option) any later version.
   *
   * This library 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 library; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 02111-1307, USA.
   */
  
  /*
   * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
   * file for a list of people on the GLib Team.  See the ChangeLog
   * files for a list of changes.  These files are distributed with
   * GLib at ftp://ftp.gtk.org/pub/gtk/. 
   */
  
  #ifndef __G_ASYNCQUEUE_H__
  #define __G_ASYNCQUEUE_H__
  
  #include <glib/gthread.h>
  
  G_BEGIN_DECLS
  
  typedef struct _GAsyncQueue     GAsyncQueue;
  
  /* Asyncronous Queues, can be used to communicate between threads
   */
  
  /* Get a new GAsyncQueue with the ref_count 1 */
  GAsyncQueue*  g_async_queue_new                (void);
  
  /* Lock and unlock an GAsyncQueue, all functions lock the queue for
   * themselves, but in certain cirumstances you want to hold the lock longer,
   * thus you lock the queue, call the *_unlocked functions and unlock it again
   */
  void          g_async_queue_lock               (GAsyncQueue *queue);
  void          g_async_queue_unlock             (GAsyncQueue *queue);
  
  /* Ref and unref the GAsyncQueue. g_async_queue_unref_unlocked makes
   * no sense, as after the unreffing the Queue might be gone and can't
   * be unlocked. So you have a function to call, if you don't hold the
   * lock (g_async_queue_unref) and one to call, when you already hold
   * the lock (g_async_queue_unref_and_unlock). After that however, you
   * don't hold the lock anymore and the Queue might in fact be
   * destroyed, if you unrefed to zero */
  void          g_async_queue_ref                (GAsyncQueue *queue);
  void          g_async_queue_ref_unlocked       (GAsyncQueue *queue);
  void          g_async_queue_unref              (GAsyncQueue *queue);
  void          g_async_queue_unref_and_unlock   (GAsyncQueue *queue);
  
  /* Push data into the async queue. Must not be NULL */
  void          g_async_queue_push               (GAsyncQueue *queue,
                                                  gpointer     data);
  void          g_async_queue_push_unlocked      (GAsyncQueue *queue,
                                                  gpointer     data);
  
  /* Pop data from the async queue, when no data is there, the thread is blocked
   * until data arrives */
  gpointer      g_async_queue_pop                (GAsyncQueue *queue);
  gpointer      g_async_queue_pop_unlocked       (GAsyncQueue *queue);
  
  /* Try to pop data, NULL is returned in case of empty queue */
  gpointer      g_async_queue_try_pop            (GAsyncQueue *queue);
  gpointer      g_async_queue_try_pop_unlocked   (GAsyncQueue *queue);
  
  /* Wait for data until at maximum until end_time is reached, NULL is returned
   * in case of empty queue*/
  gpointer      g_async_queue_timed_pop          (GAsyncQueue *queue,
                                                  GTimeVal    *end_time);
  gpointer      g_async_queue_timed_pop_unlocked (GAsyncQueue *queue,
                                                  GTimeVal    *end_time);
  
  /* Return the length of the queue, negative values mean, that threads
   * are waiting, positve values mean, that there are entries in the
   * queue. Actually this function returns the length of the queue minus
   * the number of waiting threads, g_async_queue_length == 0 could also
   * mean 'n' entries in the queue and 'n' thread waiting, such can
   * happen due to locking of the queue or due to scheduling. */
  gint          g_async_queue_length             (GAsyncQueue *queue);
  gint          g_async_queue_length_unlocked    (GAsyncQueue *queue);
  
  G_END_DECLS
  
  #endif /* __G_ASYNCQUEUE_H__ */
  
  