The DRSCallback *pcb is missing an if statement in the code when DRS Oscilloscope software isn't used when calibrating in function: int DRSBoard::CalibrateTiming(DRSCallback *pcb)

I had to add if (pcb != NULL) before each pcb call, like other functions are using so that the program doesn't segfault when the function is called like b->CalibrateTiming(NULL);

That's the only function that's missing this if statement for DRSCallback *pcb call, and there are 2 calls in this function to pcb that need fixing.