MyMod.pm, MyMod.xs, INLINE.h and Makefile.PL were created by cd'ing to the directory that contains 
this README file and running:

perl -MInlineX::C2XS -e "InlineX::C2XS::c2xs('MyMod', 'MyMod', '.', {AUTOWRAP => 1, VERSION => 0.01, WRITE_MAKEFILE_PL => 1, WRITE_PM => 1})"

Probably a good idea to verify this procedure yourself - ie remove MyMod.pm, MyMod.xs,
INLINE.h and Makefile.PL from this directory, cd to this directory and run the same one
liner. (You'll need to interchange the double-quotes and single-quotes if you're running
a nix type shell.)

'README' (this file) and 't/test.t' were hand written - just to make the demo complete.
To build MyMod just run:

perl Makefile.PL
make test

You could even run 'make install' if you want - but I don't know why you would actually
want to install this module.

It's probably not often (if ever) that you'll actually want to specify "AUTOWRAP => 1"
as in the above one liner. It's more likely that the C file you've placed in the ./src
folder will contain one or more entire functions (instead of prototype(s) that can be
autowrapped). In those "more likely" situations, the one liner that you'll be running
will be essentially as above, but without the "AUTOWRAP => 1".

The AUTOWRAP feature used in the above example works simply because 'erf' is defined
in your C compiler's standard math library.