Debugging with GDB - Commands For Completion

complete (TAB): Attempt to do completion on the text before the cursor. This is application-specific. Generally, if you are typing a filename argument, you can do filename completion; if you are typing a command, you can do command completion; if you are typing in a symbol to GDB, you can do symbol name completion; if you are typing in a variable to Bash, you can do variable name completion, and so on.
possible-completions (M-?): List the possible completions of the text before the cursor.
insert-completions (M-*): Insert all completions of the text before point that would have been generated by possible-completions.
menu-complete (): Similar to complete, but replaces the word to be completed with a single match from the list of possible completions. Repeated execution of menu-complete steps through the list of possible completions, inserting each match in turn. At the end of the list of completions, the bell is rung and the original text is restored. An argument of n moves n positions forward in the list of matches; a negative argument may be used to move backward through the list. This command is intended to be bound to TAB, but is unbound by default.
delete-char-or-list (): Deletes the character under the cursor if not at the beginning or end of the line (like delete-char). If at the end of the line, behaves identically to possible-completions. This command is unbound by default.