C++ Code to get the directory in which the currently running C++ app is running, in Mac OS X and BSD Linux

Hi I just need a code snippet which gives the directory in which the currently running C++ Mac OS X App is stored. I m not very proficient in Mac OS X programming, hence i have put out this project. I DO NOT NEED THE CURRENT WORKING DIRECTORY- because this can be different from the running app's directory. The same kind of code is also needed for BSD OS- FreeBSD/NetBSD etc. Yours sincerely, Arvind.