dtfind - find dictionary field
struct fd *dtfind (fp, fieldname)
Dtfind looks up fieldname in an open RMS dictionary file.
Fieldname points to a string of ASCII characters representing the
name of the field.
Fp is the value returned from dtdict(C-3) or dtopen(C-3).
The value returned is a pointer to a structure that is defined in
dtdict(C-3), dtopen(C-3), dtfindn(C-3)
Chapter 4, RMS Programming Guide
A value of NULL is returned if the field is not in the RMS
dictionary file or if fp is not an opened RMS dictionary file.
The returned value points to static data whose contents are
overwritten with every call.