took this picture yesterday.
I confess that i'd never heard of this model until recently when tony duell told me about it. I have established, the C interpreter supports pointers as well as structures. looks like the usual C lib is available and implicitly included. you don't include any headers.
the c_lang.zip here describes the C implementation, although this particular file is for a different machine. i'm hoping they are very similar.
http://www.silrun.info/casio/pb2000/pb2000.htm
there's another one on ebay.