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<div class="title">xStreamBufferSend</div> </div>
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<p><a class="el" href="stream__buffer_8h.html">stream_buffer.h</a></p>
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<pre>
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size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
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const void *pvTxData,
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size_t xDataLengthBytes,
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TickType_t xTicksToWait );
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<pre></pre></pre><pre><pre> Sends bytes to a stream buffer. The bytes are copied into the stream buffer.</pre></pre><pre><pre> ***NOTE***: Uniquely among FreeRTOS objects, the stream buffer
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implementation (so also the message buffer implementation, as message buffers
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are built on top of stream buffers) assumes there is only one task or
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interrupt that will write to the buffer (the writer), and only one task or
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interrupt that will read from the buffer (the reader). It is safe for the
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writer and reader to be different tasks or interrupts, but, unlike other
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FreeRTOS objects, it is not safe to have multiple different writers or
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multiple different readers. If there are to be multiple different writers
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then the application writer must place each call to a writing API function
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(such as <a class="el" href="stream__buffer_8h.html#a35cdf3b6bf677086b9128782f762499d">xStreamBufferSend()</a>) inside a critical section and set the send
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block time to 0. Likewise, if there are to be multiple different readers
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then the application writer must place each call to a reading API function
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(such as xStreamBufferRead()) inside a critical section and set the receive
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block time to 0.</pre></pre><pre><pre> Use <a class="el" href="stream__buffer_8h.html#a35cdf3b6bf677086b9128782f762499d">xStreamBufferSend()</a> to write to a stream buffer from a task. Use
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<a class="el" href="stream__buffer_8h.html#a1dab226e99230e01e79bc2b5c0605e44">xStreamBufferSendFromISR()</a> to write to a stream buffer from an interrupt
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service routine (ISR).</pre></pre><pre><pre><dl class="params"><dt>Parameters</dt><dd>
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<table class="params">
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<tr><td class="paramname">xStreamBuffer</td><td>The handle of the stream buffer to which a stream is
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being sent.</td></tr>
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<tr><td class="paramname">pvTxData</td><td>A pointer to the buffer that holds the bytes to be copied
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into the stream buffer.</td></tr>
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<tr><td class="paramname">xDataLengthBytes</td><td>The maximum number of bytes to copy from pvTxData
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into the stream buffer.</td></tr>
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<tr><td class="paramname">xTicksToWait</td><td>The maximum amount of time the task should remain in the
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Blocked state to wait for enough space to become available in the stream
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buffer, should the stream buffer contain too little space to hold the
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another xDataLengthBytes bytes. The block time is specified in tick periods,
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so the absolute time it represents is dependent on the tick frequency. The
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macro <a class="el" href="projdefs_8h.html#a353d0f62b82a402cb3db63706c81ec3f">pdMS_TO_TICKS()</a> can be used to convert a time specified in milliseconds
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into a time specified in ticks. Setting xTicksToWait to portMAX_DELAY will
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cause the task to wait indefinitely (without timing out), provided
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INCLUDE_vTaskSuspend is set to 1 in <a class="el" href="_free_r_t_o_s_config_8h.html">FreeRTOSConfig.h</a>. If a task times out
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before it can write all xDataLengthBytes into the buffer it will still write
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as many bytes as possible. A task does not use any CPU time when it is in
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the blocked state.</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>The number of bytes written to the stream buffer. If a task times
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out before it can write all xDataLengthBytes into the buffer it will still
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write as many bytes as possible.</dd></dl>
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Example use:
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<pre>
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void vAFunction( StreamBufferHandle_t xStreamBuffer )
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{
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size_t xBytesSent;
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uint8_t ucArrayToSend[] = { 0, 1, 2, 3 };
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char *pcStringToSend = "String to send";
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const TickType_t x100ms = <a class="el" href="projdefs_8h.html#a353d0f62b82a402cb3db63706c81ec3f">pdMS_TO_TICKS( 100 )</a>;</pre></pre></pre><pre><pre><pre> // Send an array to the stream buffer, blocking for a maximum of 100ms to
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// wait for enough space to be available in the stream buffer.
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xBytesSent = xStreamBufferSend( xStreamBuffer, ( void * ) ucArrayToSend, sizeof( ucArrayToSend ), x100ms );</pre></pre></pre><pre><pre><pre> if( xBytesSent != sizeof( ucArrayToSend ) )
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{
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// The call to <a class="el" href="stream__buffer_8h.html#a35cdf3b6bf677086b9128782f762499d">xStreamBufferSend()</a> times out before there was enough
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// space in the buffer for the data to be written, but it did
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// successfully write xBytesSent bytes.
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}</pre></pre></pre><pre><pre><pre> // Send the string to the stream buffer. Return immediately if there is not
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// enough space in the buffer.
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xBytesSent = xStreamBufferSend( xStreamBuffer, ( void * ) pcStringToSend, strlen( pcStringToSend ), 0 );</pre></pre></pre><pre><pre><pre> if( xBytesSent != strlen( pcStringToSend ) )
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{
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// The entire string could not be added to the stream buffer because
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// there was not enough free space in the buffer, but xBytesSent bytes
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// were sent. Could try again to send the remaining bytes.
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}
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}
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</pre> </pre></pre></div><!-- contents -->
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