dtfindk - find field numbers in secondary index
struct kd *dtfindk (fp, indexno)
An RMSfile may contain secondary indexes that are used to look up records by fields other than the primary key values. There may be several secondary indexes for one RMSfile. These secondary indexes are numbered from 1 to the number of secondary indexes in the RMSfile. Up to eight data fields can be used in one secondary index. Dtfindk returns a pointer to a structure that contains the field numbers in the secondary index specified by the indexno parameter. The value returned is a pointer to a structure that is defined in the include file <cbase/dirio.h>.
Fp is the value returned from dtdict(C-3) or dtopen(C-3).
As a special case, if dtfindk is called with a indexno value of zero, dtfindk returns the data field numbers for the primary key.
dtdict(C-3), dtopen(C-3), dtfindi(C-3)
RMS Programming Guide
A value of NULL is returned if the indexno parameter is less than zero or greater than the number of secondary indexes contained in the RMSfile or if fp is not an opened RMS dictionary file.
The returned value points to static data whose contents are overwritten with every call.