I have a basic project running, but tasks are not doing what I want so I would like to use the traceTASKSWITCHEDIN/OUT macros to output something to a logic analyzer. So here is my code

void setLogOutput (unsigned long c)
{
    int a;
    if (c == 0)
        a = 0;
}

#define traceTASK_SWITCHED_IN() setLogOutput(pxCurrentTCB->uxTaskNumber)
#define traceTASK_SWITCHED_OUT() setLogOutput(0)
#include "FreeRTOS.h"

Obviously setLogOutput doesn’t do anything right now, and I know it. But the point is that neighter SWITCHEDIN nor SWITCHEDOUT are ever called or compiled. Breakpoints in tasks.c are broken. I cannot understand what I am doing wrong, could anybody please help me?

Where have you defined the macros? The easiest place to put them, to get the correct include order, is at the bottom of FreeRTOSConfig.h. Regards.

Hi, You could try: ~~~~~~ volatile unsigned int dummy; void setLogOutput (unsigned long c) { dummy++; } ~~~~~~ It is possible that optimiser ignores the code, because it does nothing. GCC is very clever with this: it sees when a variable is only used in the left-hand size of expressions, and in that case it will never be implemented. ‘volatile’ might help or better: print the variable somewhere. Regards.

I’ve been seeing GCC get more and more clever about working around my ways to keep variables/code from being deleted. There was a time when global variables were safe, but not now. I’ve tried debugging with no optimization, but that just blows the code up where it doesn’t fit. I now run with -Og which seems to be a reasonable compromise most of the time. On 06/04/2014 09:56 AM, Hein Tibosch wrote:

GCC is very clever with this: it sees when a variable is only used in the left-hand size of expressions, and in that case it will never be implemented. ‘volatile’ might help or better: print the variable somewhere.

— Jerry Durand, Durand Interstellar, Inc. www.interstellar.com tel: +1 408 356-3886, USA toll free: 1 866 356-3886 Skype: jerrydurand

Yes indeed, gcc also makes global variables disappear, even if they appear in several modules (as LHS only). ~~~~~~ const char ipmarker[32] = “dEfAuLtIp192.168.2.116″; void somefunction() { asm (“” : : “r” (ipmarker) : “cc”); } ~~~~~~ This trick worked to get a const string included in the code without ever actually reading it. Note that some_function() must be called

Sorry I thought I answered this but evidently I didn’t. Putting the macro at the end of FreeRTOSConfig.h solved my problem.