child process statistics

Does anyone know how to get the process statistics (cputime, page faults, etc.) for a child process? When the child process has terminated, before doing getAnyProcessStatus on it, I'd like to get its statistics. Browsing the libraries documentation didn't turn anything up. I couldn't even find what I want at the Unix level among man pages. (I'm happy to write some FFI code to access system routines if I can locate the right ones.) Dean