m-file knowing its own source location?

[forkandwait]

Hi all,

Is there a way for an m-file to reference its source code location in the 
filesystem?  Note that I am not asking about referencing the current working 
directory, but rather the directory where the m source is stored.

So that if I store foo.m in /home/forkandwait/mfuncs/foo.m, but my current 
working directory is /home/forkandwait, I can still get foo to know it is 
stored in mfuncs?

The reason is that I want to write a bunch of data access functions and store 
them in the same dir as the data, then genpath addpath to get them.  However, I 
also want to avoid hardcoding pathnames.  This way, usapopulation() will always 
know to look "next" to where its source code is stored to read in a file called 
usapopulation.txt, munge it, and return various useful matrices; usapop() will 
be able to do this no matter where the octave interpreter is running.  

If this seems like a bad pattern, let me know that too.

Thanks again 
F&W