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<div class="title">xMessageBufferCreate</div> </div>
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<p><a class="el" href="message__buffer_8h.html">message_buffer.h</a></p>
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<pre>
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MessageBufferHandle_t <a class="el" href="message__buffer_8h.html#a2959cd0e3d2bd20d46908e5c9872be36">xMessageBufferCreate( size_t xBufferSizeBytes )</a>;
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</pre><p>Creates a new message buffer using dynamically allocated memory. See <a class="el" href="message__buffer_8h.html#acc84f4a15dbd39ecbad35f7337e78b2c">xMessageBufferCreateStatic()</a> for a version that uses statically allocated memory (memory that is allocated at compile time).</p>
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<p>configSUPPORT_DYNAMIC_ALLOCATION must be set to 1 or left undefined in <a class="el" href="_free_r_t_o_s_config_8h.html">FreeRTOSConfig.h</a> for <a class="el" href="message__buffer_8h.html#a2959cd0e3d2bd20d46908e5c9872be36">xMessageBufferCreate()</a> to be available.</p>
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<dl class="params"><dt>Parameters</dt><dd>
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<table class="params">
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<tr><td class="paramname">xBufferSizeBytes</td><td>The total number of bytes (not messages) the message buffer will be able to hold at any one time. When a message is written to the message buffer an additional sizeof( size_t ) bytes are also written to store the message's length. sizeof( size_t ) is typically 4 bytes on a 32-bit architecture, so on most 32-bit architectures a 10 byte message will take up 14 bytes of message buffer space.</td></tr>
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</table>
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</dd>
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</dl>
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<dl class="section return"><dt>Returns</dt><dd>If NULL is returned, then the message buffer cannot be created because there is insufficient heap memory available for FreeRTOS to allocate the message buffer data structures and storage area. A non-NULL value being returned indicates that the message buffer has been created successfully - the returned value should be stored as the handle to the created message buffer.</dd></dl>
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<p>Example use: </p><pre></pre><pre>void vAFunction( void )
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{
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MessageBufferHandle_t xMessageBuffer;
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const size_t xMessageBufferSizeBytes = 100;</pre><pre> // Create a message buffer that can hold 100 bytes. The memory used to hold
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// both the message buffer structure and the messages themselves is allocated
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// dynamically. Each message added to the buffer consumes an additional 4
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// bytes which are used to hold the lengh of the message.
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xMessageBuffer = <a class="el" href="message__buffer_8h.html#a2959cd0e3d2bd20d46908e5c9872be36">xMessageBufferCreate( xMessageBufferSizeBytes )</a>;</pre><pre> if( xMessageBuffer == NULL )
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{
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// There was not enough heap memory space available to create the
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// message buffer.
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}
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else
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{
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// The message buffer was created successfully and can now be used.
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}</pre><pre></pre> </div><!-- contents -->
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