When in GDB mode, the user is mostly interested in working with the GDB console. That is, sending commands to GDB and receiving data back from GDB. Almost all data passed into this window is directly sent to readline and then to GDB.
It is important to understand that CGDB parses the keys entered in the GDB window and has the first chance at dealing with them. If it is interested in the keys, it will handle them. Below is a list of keys that CGDB is interested in, and does not pass along any further.
Any other keys, besides the ones above, CGDB is currently not interested in. CGDB will pass along these keys to the readline library. When readline has determined that a command has been received, it alerts CGDB, and a command is then sent to GDB. This is the same method used when invoking GDB directly.