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xQueueSendToFrontFromISR macro
This is a macro that calls xQueueGenericSendFromISR(). Post an item to the front of a queue. It is safe to use this macro from within an interrupt service routine. Items are queued by copy not reference so it is preferable to only queue small items, especially when called from an ISR. In most cases it would be preferable to store a pointer to the item being queued. Example usage for buffered IO (where the ISR can obtain more than one value per call):
void vBufferISR( void )
{
char cIn;
BaseType_t xHigherPrioritTaskWoken;
// We have not woken a task at the start of the ISR.
xHigherPriorityTaskWoken = pdFALSE;
// Loop until the buffer is empty.
do
{
// Obtain a byte from the buffer.
cIn = portINPUT_BYTE( RX_REGISTER_ADDRESS );
// Post the byte.
xQueueSendToFrontFromISR( xRxQueue, &cIn, &xHigherPriorityTaskWoken );
} while( portINPUT_BYTE( BUFFER_COUNT ) );
// Now the buffer is empty we can switch context if necessary.
if( xHigherPriorityTaskWoken )
{
taskYIELD ();
}
}
Syntax
#define xQueueSendToFrontFromISR( xQueue, pvItemToQueue, pxHigherPriorityTaskWoken ) xQueueGenericSendFromISR( ( xQueue ), ( pvItemToQueue ), ( pxHigherPriorityTaskWoken ), queueSEND_TO_FRONT )
Return value
pdTRUE if the data was successfully sent to the queue, otherwise errQUEUE_FULL.