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Move GAsyncQueue docs inline
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Asynchronous Queues
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Asynchronous Queues
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<!-- ##### SECTION Short_Description ##### -->
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<!-- ##### SECTION Short_Description ##### -->
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asynchronous communication between threads
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<!-- ##### SECTION Long_Description ##### -->
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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<para>
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Often you need to communicate between different threads. In general
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it's safer not to do this by shared memory, but by explicit message
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passing. These messages only make sense asynchronously for
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multi-threaded applications though, as a synchronous operation could as
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well be done in the same thread.
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</para>
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<para>
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Asynchronous queues are an exception from most other GLib data
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structures, as they can be used simultaneously from multiple threads
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without explicit locking and they bring their own builtin reference
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counting. This is because the nature of an asynchronous queue is that
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it will always be used by at least 2 concurrent threads.
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</para>
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<para>
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For using an asynchronous queue you first have to create one with
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g_async_queue_new(). A newly-created queue will get the reference
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count 1. Whenever another thread is creating a new reference of (that
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is, pointer to) the queue, it has to increase the reference count
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(using g_async_queue_ref()). Also, before removing this reference, the
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reference count has to be decreased (using
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g_async_queue_unref()). After that the queue might no longer exist so
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you must not access it after that point.
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</para>
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<para>
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A thread, which wants to send a message to that queue simply calls
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g_async_queue_push() to push the message to the queue.
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</para>
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<para>
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A thread, which is expecting messages from an asynchronous queue
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simply calls g_async_queue_pop() for that queue. If no message is
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available in the queue at that point, the thread is now put to sleep
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until a message arrives. The message will be removed from the queue
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and returned. The functions g_async_queue_try_pop() and
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g_async_queue_timed_pop() can be used to only check for the presence
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of messages or to only wait a certain time for messages respectively.
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</para>
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<para>
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For almost every function there exist two variants, one that locks the
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queue and one that doesn't. That way you can hold the queue lock
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(acquire it with g_async_queue_lock() and release it with
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g_async_queue_unlock()) over multiple queue accessing
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instructions. This can be necessary to ensure the integrity of the
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queue, but should only be used when really necessary, as it can make
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your life harder if used unwisely. Normally you should only use the
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locking function variants (those without the suffix _unlocked)
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</para>
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</para>
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<!-- ##### SECTION See_Also ##### -->
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<!-- ##### SECTION See_Also ##### -->
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@ -71,9 +22,7 @@ locking function variants (those without the suffix _unlocked)
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<!-- ##### STRUCT GAsyncQueue ##### -->
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<!-- ##### STRUCT GAsyncQueue ##### -->
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<para>
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<para>
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The #GAsyncQueue struct is an opaque data structure, which represents
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an asynchronous queue. It should only be accessed through the
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<function>g_async_queue_*</function> functions.
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</para>
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</para>
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@ -34,7 +34,60 @@
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#include "gthread.h"
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#include "gthread.h"
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/**
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* SECTION: async_queues
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* @title: Asynchronous Queues
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* @short_description: asynchronous communication between threads
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*
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* Often you need to communicate between different threads. In general
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* it's safer not to do this by shared memory, but by explicit message
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* passing. These messages only make sense asynchronously for
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* multi-threaded applications though, as a synchronous operation could
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* as well be done in the same thread.
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*
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* Asynchronous queues are an exception from most other GLib data
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* structures, as they can be used simultaneously from multiple threads
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* without explicit locking and they bring their own builtin reference
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* counting. This is because the nature of an asynchronous queue is that
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* it will always be used by at least 2 concurrent threads.
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*
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* For using an asynchronous queue you first have to create one with
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* g_async_queue_new(). A newly-created queue will get the reference
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* count 1. Whenever another thread is creating a new reference of (that
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* is, pointer to) the queue, it has to increase the reference count
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* (using g_async_queue_ref()). Also, before removing this reference,
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* the reference count has to be decreased (using g_async_queue_unref()).
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* After that the queue might no longer exist so you must not access
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* it after that point.
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*
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* A thread, which wants to send a message to that queue simply calls
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* g_async_queue_push() to push the message to the queue.
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*
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* A thread, which is expecting messages from an asynchronous queue
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* simply calls g_async_queue_pop() for that queue. If no message is
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* available in the queue at that point, the thread is now put to sleep
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* until a message arrives. The message will be removed from the queue
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* and returned. The functions g_async_queue_try_pop() and
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* g_async_queue_timed_pop() can be used to only check for the presence
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* of messages or to only wait a certain time for messages respectively.
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*
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* For almost every function there exist two variants, one that locks
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* the queue and one that doesn't. That way you can hold the queue lock
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* (acquire it with g_async_queue_lock() and release it with
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* g_async_queue_unlock()) over multiple queue accessing instructions.
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* This can be necessary to ensure the integrity of the queue, but should
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* only be used when really necessary, as it can make your life harder
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* if used unwisely. Normally you should only use the locking function
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* variants (those without the suffix _unlocked)
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*/
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/**
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* GAsyncQueue:
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*
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* The GAsyncQueue struct is an opaque data structure, which represents
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* an asynchronous queue. It should only be accessed through the
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* <function>g_async_queue_*</function> functions.
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*/
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struct _GAsyncQueue
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struct _GAsyncQueue
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{
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{
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GMutex *mutex;
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GMutex *mutex;
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