glib/gasyncqueue.h

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 #ifndef __G_ASYNCQUEUE_H__
  28 #define __G_ASYNCQUEUE_H__
  29
  30 #include <glib/gthread.h>
  31
  32 G_BEGIN_DECLS
  33
  34 typedef struct _GAsyncQueue     GAsyncQueue;
  35
  36 /* Asyncronous Queues, can be used to communicate between threads
  37  */
  38
  39 /* Get a new GAsyncQueue with the ref_count 1 */
  40 GAsyncQueue*  g_async_queue_new                (void);
  41
  42 /* Lock and unlock an GAsyncQueue, all functions lock the queue for
  43  * themselves, but in certain cirumstances you want to hold the lock longer,
  44  * thus you lock the queue, call the *_unlocked functions and unlock it again
  45  */
  46 void          g_async_queue_lock               (GAsyncQueue *queue);
  47 void          g_async_queue_unlock             (GAsyncQueue *queue);
  48
  49 /* Ref and unref the GAsyncQueue. g_async_queue_unref_unlocked makes
  50  * no sense, as after the unreffing the Queue might be gone and can't
  51  * be unlocked. So you have a function to call, if you don't hold the
  52  * lock (g_async_queue_unref) and one to call, when you already hold
  53  * the lock (g_async_queue_unref_and_unlock). After that however, you
  54  * don't hold the lock anymore and the Queue might in fact be
  55  * destroyed, if you unrefed to zero */
  56 void          g_async_queue_ref                (GAsyncQueue *queue);
  57 void          g_async_queue_ref_unlocked       (GAsyncQueue *queue);
  58 void          g_async_queue_unref              (GAsyncQueue *queue);
  59 void          g_async_queue_unref_and_unlock   (GAsyncQueue *queue);
  60
  61 /* Push data into the async queue. Must not be NULL */
  62 void          g_async_queue_push               (GAsyncQueue *queue,
  63                                                 gpointer     data);
  64 void          g_async_queue_push_unlocked      (GAsyncQueue *queue,
  65                                                 gpointer     data);
  66
  67 /* Pop data from the async queue, when no data is there, the thread is blocked
  68  * until data arrives */
  69 gpointer      g_async_queue_pop                (GAsyncQueue *queue);
  70 gpointer      g_async_queue_pop_unlocked       (GAsyncQueue *queue);
  71
  72 /* Try to pop data, NULL is returned in case of empty queue */
  73 gpointer      g_async_queue_try_pop            (GAsyncQueue *queue);
  74 gpointer      g_async_queue_try_pop_unlocked   (GAsyncQueue *queue);
  75
  76 /* Wait for data until at maximum until end_time is reached, NULL is returned
  77  * in case of empty queue*/
  78 gpointer      g_async_queue_timed_pop          (GAsyncQueue *queue,
  79                                                 GTimeVal    *end_time);
  80 gpointer      g_async_queue_timed_pop_unlocked (GAsyncQueue *queue,
  81                                                 GTimeVal    *end_time);
  82
  83 /* Return the length of the queue, negative values mean, that threads
  84  * are waiting, positve values mean, that there are entries in the
  85  * queue. Actually this function returns the length of the queue minus
  86  * the number of waiting threads, g_async_queue_length == 0 could also
  87  * mean 'n' entries in the queue and 'n' thread waiting, such can
  88  * happen due to locking of the queue or due to scheduling. */
  89 gint          g_async_queue_length             (GAsyncQueue *queue);
  90 gint          g_async_queue_length_unlocked    (GAsyncQueue *queue);
  91
  92 G_END_DECLS
  93
  94 #endif /* __G_ASYNCQUEUE_H__ */
  95