Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Tue, 10 Mar 1998 16:18:56 +0100

Hello Marty (and all the others),

another proposal (suggested by Goetz Pfeiffer): Currently there is a
'Symb' device support for ai, ao, longin, longout, stringin and
stringout records. Their purpose is to associate the records VALue with
some globally visible VxWorks variable through the use of VxWorks'
symbol table. But the implementation is rather crude: Neither is there
any protection against race conditions while copying the value, nor is
there the possibility to supply the name of the symbol independently
from the record's name resp. naming convention.

Both can be mended easily:

(1) To protect the data transport, simply add some

	intLock()
	...
	intUnlock()

pairs around the critical section, which is for example in devAiSymb the
single line

	pai->val = *(double *)(pai->dpvt);

(2) To enable record name independent symbol names, check the hw link if
it equals INST_IO. If yes, get the symbol name from the link, otherwise
(ie the link is CONSTANT) use the previous algorithm as a fallback
method.

I'd volunteer to code the proposed changes, if there is interest and
there are no objections to them.

	Ben
-- 
The Notorious Neb Nesknarf
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System