A user can typically set there control flow behavior by using the stty
command like so stty -ixon -ixoff. This will disable control flow on
the terminal where CGDB is started. If you want to turn control flow back
on you can type stty ixon ixoff. If flow control is on, when the user
types Ctrl-s, the terminal stops. When the user types Ctrl-q, the
terminal restarts. When using readline, the Ctrl-s character usually does
a forward search. So, if you want to get this, or other functionality out of
readline, simply turn off control flow and start CGDB.