Difference between revisions of "GQUEUE"
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<code>gfxBufferGet()</code> will return a pointer to a free buffer in the buffer pool (if any). The buffer is marked as used until it has been released using <code>gfxBufferRelease()</code>. | <code>gfxBufferGet()</code> will return a pointer to a free buffer in the buffer pool (if any). The buffer is marked as used until it has been released using <code>gfxBufferRelease()</code>. | ||
Note that some modules like the [[GAUDIO]] module that take a buffer as a parameter usually release the buffer automatically. | Note that some modules like the [[GAUDIO]] module that take a buffer as a parameter usually release the buffer automatically. | ||
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| + | As <code>gfxBufferGet()</code> takes a timeout parameter, this function polls until either a free buffer is available or the timeout is exceeded. To avoid this, <code>gfxBufferIsAvailable()</code> can be used to check if there is a free buffer before hand. | ||
== Queues == | == Queues == | ||
Revision as of 23:50, 4 July 2014
The GQUEUE modules does provide queues and buffers.
API reference
The API reference of the GQUEUE module can be found here.
Buffers
Buffers are used to pass data from one module to another. For example, buffers are used to read an audio file from an SD-Card using the GFILE module and output it using the GAUDIO module.
Allocation
A pool of buffers can be allocated using gfxBufferAlloc(num, size) where num is the number of buffers and size the size per buffer. The created buffer pool is global. It is not possible to have more than one buffer pool.
Memory once dedicated to become a buffer cannot be freed anymore. Therefore, the number and size of the buffers allocated should be chosen carefully.
Handling
gfxBufferGet() will return a pointer to a free buffer in the buffer pool (if any). The buffer is marked as used until it has been released using gfxBufferRelease().
Note that some modules like the GAUDIO module that take a buffer as a parameter usually release the buffer automatically.
As gfxBufferGet() takes a timeout parameter, this function polls until either a free buffer is available or the timeout is exceeded. To avoid this, gfxBufferIsAvailable() can be used to check if there is a free buffer before hand.
Queues
Although the queues provided by the GQUEUE module are mainly used internally, these features are still accessible for the user.
ToDo
