Use the ZPRINT command to display source code lines selected by its argument. ZPRINT allows you to display the source for the current routine and any other related routines. Use the ZPRINT command to display the last call level.

Example:

        GTM>ZPRINT beg
        beg for read !,"Name: ",name do name
        

This example uses a ZPRINT command to print the line indicated as the call at the top of the stack. Notice that the routine has an error in logic. The line starting with the label beg has a FOR loop with no control variable, no QUIT, and no GOTO. There is no way out of the FOR loop.