Values optimized Out GDB G++

I assume you use -g (and possibly also -ggdb) to generate debugging information ?

The -O0 switch does indeed mean "no optimization". It is still possible that it performs certain basic optimizations (things like unreachable code for example - see below) however, but it tries to keep the resulting generated code as close as possible to the source code.

Can you give an example of what your compiler optimized at level -O0 ?

#include <stdio.h>
 
int main(void) {
  printf("Before");    /* -O0 : code generated */
  return 0;
  printf("After");     /* -O0 : no code generated (unreachable code) */
}

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For example in the code below i cannot watch the NoClassObs variable or the Randomnumber. Another problem is that when I step through the code gdb (in kdevelop) seems to randomly jump and even stops and comment lines strangly enough.

          while (CurrentClass != LastClass) {                                
            NoClassObs = (unsigned int)((*CurrentClass).Ratio * PartitionSize);
            for (unsigned int i=0; i < NoClassObs; i++) {                      
              RandomNumber = GetRandomNumber((*CurrentClass).Observations.size()-1);
             CurrentObservation += (RandomNumber);
             (*CurrentPartition).AddObservation(*CurrentObservation);          
             (*CurrentClass).Observations.erase(CurrentObservation);
            }
            CurrentClass++;
          }

Maybe you should try running gdb yourself (instead of using the one in kdevelop), and see if that works better.

Just to add to what duncan_roe has said (and I've been caught out by this before so it can happen) are you sure your latest version of the code actually builds? Are you trying to debug an old version of the compiled code against a newer source. This sounds like such a daft thing to do but I promise, it can and does happen (I feel so silly admitting this :) ).

thanks