[Bug-cpio] Gnu archive library?

[Mike Gran]

Hi-
 
I was wondering if there was a GNU solution for a library and 
C API to read files from an archive file of some common format:
tar, cpio, pax, or whatever.  It doesn't matter which one.
 
I'm trying to create and use an archive that my program will
use as a read-only filesystem.
 
Searching the internet gives me some references to libraries named
libcpio and libpax, but, no obvious links to if and how
they could be used.
 
The only documented GNU soltuion that I've found so far would be
to store my files as a CD iso9660 format file and then use
libiso9660 from GNU libcdio, but, it seems rather heavyweight
for my purposes.
 
Any ideas?
 
Thanks,
 
Mike Gran