The breturn value of PKEYREQ tells how many records were read into the buffer. If breturn is less than bavail, the buffer was not large enough to hold all matching records. Make another call to DoBatch() to retrieve the rest of the records.
To process the next group of records in the batch, call DoBatch() with a mode value of BAT_NXT. btotal and bavail are not changed, but breturn reflects the number of records in the buffer for this DoBatch() call.