27.6.5 GDB Graphical Interface
The command M-x gdb starts GDB in an IDE-like interface, with
specialized buffers for controlling breakpoints, stack frames, and
other aspects of the debugger state. It also provides additional ways
to control the debugging session with the mouse, such as clicking in
the fringe of a source buffer to set a breakpoint there.
To run GDB using just the GUD interaction buffer interface, without
these additional features, use M-x gud-gdb (see Starting GUD). You must use this if you want to debug multiple programs
within one Emacs session, as that is currently unsupported by M-x gdb.
Internally, M-x gdb informs GDB that its screen size is
unlimited; for correct operation, you must not change GDB’s screen
height and width values during the debugging session.