Pre and/or post processing of system calls?

From: sn (emailismylife_at_yahoo.com)
Date: 02/28/04 

Date: 27 Feb 2004 16:31:37 -0800

Hi,

Is it possible to execute some pre and/or post processing code
before/after any system call is executed by *any* process? How? Even
if it is possible for just 'exit()' it should be close enough for what
i want to achieve.

Thanks