Re: Save file exclusively locked when displaying?

David,

A "save file" is not really a true "file" in the traditional sense, underneath is an MI "dump" object (a kind of space) that contains the saved object(s).

You cannot read and update individual "records" in a save file; it can only be read or written in its entirety, from start to end ... as a sort of "atomic" operation.  If you have ever canceled a SAVOBJ command and tried to display an "incomplete" save file, you will get errors.

So, it "makes sense" to me that IBM places an *EXCLRD lock on the save file, in addition to the usual *SHRRD lock when the file is opened.

Just saying ...

Mark S. Waterbury

On Monday, August 2, 2021, 12:16:07 PM EDT, David Gibbs via MIDRANGE-L <midrange-l@xxxxxxxxxxxxxxxxxx> wrote:

On 8/2/21 10:19 AM, Rob Berendt wrote:
Why know why?  To decide if you can still view it and not lock it?

Idle curiosity, mostly.

If it didn't lock it, it would freak me out if the contents of
DSPSAVF suddenly changed while I was paging through it.

Well, actually, no. That's not valid at all.

A save file (or any file / part of a file) should be locked when it's
being updated, not when it's being viewed.

So saving to a save file should lock the object exclusively ... and
error out if it can't get the exclusive lock.

Displaying, or reading (in the case of a transfer), should NOT lock a
save file because it's not being changed.


david