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