isymchoose

isymchoose can automatically determine which symbols (functions, types, enumerators, etc.) are available in a given C language source file and present you with a list of completion possibilities, including return types and argument lists. With a little help, it can also display documentation for symbols. At its simplest, it functions as a keystroke-economical, context-sensitive symbol completer. However, additional features exist that aim to let the programmer remember in general, fuzzy terms what their libraries can do and quickly find and insert what is needed, rather than having to remember or awkwardly look up exactly what everything is called, what arguments are required, etc.