Halting on a line in C++ only if a condition is true

Often a particular part of your program works fine for the first few thousand times, but fails under certain conditions. You don't want to set a simple line breakpoint because you will have to keep entering GO.

Example: sample C++ program for debugging

For example, in main you want to stop in T_DIVIDE only if the divisor is 0 (before the exception occurs). Set the breakpoint like this:
AT 40 { if(num2 != 0) GO; }
Line 40 is the statement labeled  CALC2 . The command causes z/OS® Debugger to stop at line 40. If the value of num is not 0, the program will continue. z/OS Debugger stops on line 40 only if num2 is 0.