Experimental Physics and
Industrial Control System

Kay-Uwe Kasemir <[email protected]> · Wed, 19 Oct 2005 09:10:05 -0400

On Oct 19, 2005, at 08:44 , Marty Kraimer wrote:

processLink = [3] {
       {pvname = "incA"; wait=true},
       {pvname = "incB"; wait=true,block=true},
       {pvname = "getSample"; wait=true;}
}

The link for getSample will not be requested until both incA and

incB complete. I think this is intuitive.

There is a problem for separate link fields rather than an array

of links.

Now the order in which the fields appear in the record matter.

The order can never be changed or databases will break

I still hold up my already expressed concerns:

    * The configuration has different lines  for "incA" and "incB",

 while in the course of record execution they are treated the

same.

??? Since this is an array of links the semantics are do link[0]

then link[1], ... Thus the order is clear.

If the idea is that incA and incB should process
"in parallel", then as Ralph said, the database designer doesn't
need to know how that's done in detail.
It only matters that incA & incB are somehow processed
together, we wait for them to finish, then the next
record gets processed.
A nested, grouped syntax would express that,
where 'wait' or 'block' is always the default:

processLink =
{
       # Cause incA and incB to process
       { pvname[] = {"incA", "incB"} }
       # When they're both done, process getSample
       { pvname = "getSample"}
}

-Kay

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System