From: Benjamin F. <ben...@he...> - 2012-02-26 21:04:48
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All the protocol specification says (*) about the structure of requests is that the specifics of a request are contained in the pvRequest field, that this is user data (more specifically: a structure), and that it must be accompanied by introspection data in a field named pvRequestIF. But it says nothing further about the request structure. A server that answers to all requests with a bad status ("request format not understood") must be regarded as conforming with respect to the pvAccess protocol. I know that the pvIOC (note: not the pvData) docs have something to say about how requests are constructed (http://epics- pvdata.hg.sourceforge.net/hgweb/epics-pvdata/pvIOCJava/raw- file/tip/documentation/pvIOCJava.html#L9251). It is clear that this has been done because the request structure is not only used for pvAccess, but also for direct access using the pvCopy API. So, is the intention here that the exact content of the pvRequest message field is deliberately left unspecified? Or should the protocol spec say something like "Requests have to be constructed according to <insert above reference to chapter of pvIOC docs>."? In both cases, I would expect an explanation somewhere before the detailed message descriptions. Actually, all this should be a part of the definition/explanation of the term 'request' i.e. in a separate chapter. Cheers Ben (*) Or at least I could infer this, or maybe I know it because I have been told on the list, I remember I had to ask about this when reading the spec for the first time, but that was long ago. ________________________________ Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V. Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. Vorsitzende Dr. Beatrix Vierkorn-Rudolph Geschäftsführerin: Prof. Dr. Anke Rita Kaysser-Pyzalla Sitz Berlin, AG Charlottenburg, 89 HRB 5583 Postadresse: Hahn-Meitner-Platz 1 D-14109 Berlin http://www.helmholtz-berlin.de |