A running program can initiate a gdb session by calling the function
Debug( if (counter == 31523 && ptr == (void*)0x40013fa0) // When to start debugging? attach_gdb(); ); ptr->foobar++; // The debugging will start at this line.
attach_gdb() opens an xterm (or whatever is configured in the rcfile) and starts the gdb session inside it.
After exiting gdb the application will continue running.
In order for
attach_gdb() to work, you will need to call
read_rcfile() at the start of your application.