||Deletes a record physically from a table
||DELREC(db : INTEGER; recno : INTEGER) : INTEGER
||db : table handle from OPENDB
recno : physical number of record that is to delete
||Physical record number of that record which follows to the place of the deleted one.
tdbengine deletes a record by overwriting it with the so far last error and by decreasing the size of the table by one entry (deleting the last record only the size is decreased).
The return value of the function depends on the actual access:
Access via physical numbers of records -> recno (resp. recno-1 if recno=last record of the table)
Access via marking list -> number of the next record in the marking list (resp. the previously if recno was the last entry in the marking list, resp. 0 if recno was not in the marking list)
Access via index: Number of the next record with reference to the order defined in the index (resp. the previous one if there is no more next one)