Thanks again Sergey for your appreciated quick reply ;-)

Yes it's actually what I want to do, pass a variable that already contains a value, modify it and return it to the caller.

So If I understand you, I could:

USP_O_MYPROC @VALUE INT OUTPUT
...
...
SET @VALUE = @VALUE + 1
IF @VALUE IS NULL SET @VALUE = 0
RETURN


When I call the SP, I simply do:
SET @tata = 120
EXEC USP_O_MYPROC @tata OUTPUT
-- @tata should now be 121...



Thanks.