Hints-for-C-Library-Functions-B is a project mainly written in Vim Script, it's free.
while typing a C function, a prototype is shown (man3 based)
This is a mirror of http://www.vim.org/scripts/script.php?script_id=1826
This script may be manually sourced or, if placed in .vim/ftplugin/c, will be automatically sourced whenever a C file is edited (which is where vimball will put it). The prototypes within it are based on gcc's /usr/share/man/man3 directory.
This plugin is truly simple to use: after one has typed a function name, a protype "hint" will be shown.
ex. printf(
will result in
int printf(const char * format, ...)
being echo'd at the bottom of the display.You'll probably want your cmdheight option set to at least two (ie. set ch=2).
(see vimscript#1825 for man-2 function hints)