RFA

Locate record with the specified RFA

WTSupported in traditional Synergy on Windows
WNSupported in Synergy .NET on Windows
USupported on UNIX
VSupported on OpenVMS
RFA:match_rfa

Arguments

match_rfa

One of the following:

rfa = The RFA. (a6)

grfa = The global RFA (GRFA). (a10)

Discussion

The RFA qualifier causes the FIND, READ, and WRITE statements to position to the specified RFA. However, the RFA qualifier on an UNLOCK statement allows a specified lock to be released.

Rfa is an a6 variable that has been obtained either by the GETRFA qualifier or the GETRFA subroutine.

Using GRFAs can help you implement optimistic locking. (See Optimistic locking technique for more information.)

If you’ve used GETRFA:grfa on a previous READ or READS statement and then saved off the GRFA that is returned, a READ or READS with the RFA qualifier can attempt to reacquire the same record. (For a relative file, you can use WRITE to write a record by GRFA without rereading it.) If a record has changed between reads (or before it is written), a “Record not same” error ($ERR_RECNOT) will result because the CRC no longer matches. Thus, on a READ the record will still be read, but on a WRITE the record will not be written. To retrieve the CRC portion of the GRFA, use the %GETCRC routine.

Note

RFA:grfa can be used on the FIND statement for ISAM and relative files and on the READ and WRITE statements for ISAM, stream, sequential, relative, and block files. The CRC portion of the GRFA is ignored on the FIND statement, the UNLOCK statement, and the POSRFA routine for ISAM and relative files. Note that when you get the GRFA from one of these statements, the CRC portion will be ignored by FIND, UNLOCK, and POSRFA when you try to use it there.

The following built‑in types are available when declaring an RFA or GRFA variable.

See also