In the FreeRTOS.h file, there are lots of definition as shown in below: #ifndef traceTASK_INCREMENT_TICK #define traceTASK_INCREMENT_TICK( xTickCount ) #endif
the statement “#define traceTASK_INCREMENT_TICK( xTickCount )” seems actually doing nothing, I’m not quite understand it. Could anyone kindly help?
BaseType_t xTaskIncrementTick( void )
{
TCB_t * pxTCB;
TickType_t xItemValue;
BaseType_t xSwitchRequired = pdFALSE;
/* Called by the portable layer each time a tick interrupt occurs.
Increments the tick then checks to see if the new tick value will cause any
tasks to be unblocked. */
traceTASK_INCREMENT_TICK( xTickCount );
if( uxSchedulerSuspended == ( UBaseType_t ) pdFALSE )
...
For every tick increment, it calls a macro or a function called traceTASK_INCREMENT_TICK().
Now if you want to do something during every tick-increment, you can define the macro in a new way. Write that new definition in you FreeRTOSConfig.h file, so it will be included beforeinclude/FreeRTOS.h.
When you run this, your function will be called for every increment.
So what you see in FreeRTOS is giving a proper default value for every macro.
Be careful: most trace-macro’s are being called from critical situations. The task scheduler is often temporarily disabled, interrupts might have been disabled. When a trace macro is called from the idle task, there are many things you’re not supposed to do, and the task-stack will be very small.
The good thing about trace macro’s: they avoid the necessity to change the FreeRTOS source code. Regards.