Starting A gdb Session From A Running Program

A running program can initiate a gdb session by calling the function attach_gdb().For example,

Debug(
  if (counter == 31523 && ptr == (void*)0x40013fa0)   // When to start debugging?
    attach_gdb();
);
 
ptr->foobar++;        // The debugging will start at this line.

The function 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.