We have used this feature in several systems.  It is done with an
FSETMODE(fnum,1) call.

This is a particularly useful feature with interactive programs where it
must be guaranteed that changes to a file will not be lost by a program
or system abort (Qedit's work file is an example, I believe).  A place
where we have used it in batch jobs is when FUPDATE's to a file must be
synchronized with changes in a database.  Image and Allbase will
preserve those changes, only XM can do it for flat files.

Despite the slight overhead described by Stan, it is less expensive than
using regular FCONTROL calls to post records to disc.  And one
millisecond per record seems like a small price to pay for data
integrity.

Rob Joseph
The NPD Group
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