Cproto is a program that generates function prototypes and variable declarations from C source code. It can also convert function definitions between the old style and the ANSI C style. This conversion overwrites the original files, so make a backup copy of your files in case something goes wrong. The program isn't confused by complex function definitions as much as other prototype generators because it uses a yacc generated parser. By ignoring all the input between braces, I avoided implementing the entire C language grammar.