Re: 5250 Data Stream

[dhandy@xxxxxxxxxxx (Douglas Handy)]

Benjamin,

>Is it possible to write 5250 data stream directly to a twinax attached
>terminal? I think the DDS keyword USRDFN can be used for that purpose, 

Correct.  The USRDFN keyword exists only to allow you to write 5250
data streams directly.  You must provide the complete data stream,
including the leading length bytes, the send or send/rcv or whatever
opcode byte, all WTD, SOH, SBA, SOF, FFW, FCW, IC, etc orders, and a
trailing ReadInput command if the format has input capable fields.

The 5250 data stream is documented in the 5494 Functions Reference
manual, which should be on your softcopy CD.

I'd caution against using it in a production line-of-business
application though, unless you can make a strong case for the need.
It is not something that very many people can maintain.  If you do use
it, make sure you document what you do very carefully.

Instead of USRDFN (also known as UDDS, User Defined Data Streams),
consider the Dynamic Screen Manager APIs.  IBM added these in about
'92 so that you can dynamically control the screen format without the
need to directly work at the data stream level.  

This may be more maintainable than using UDDS itself.  If you really
want a sample UDDS program, I can send you a simple example.  But I've
never deployed UDDS (or DSM) in a production app, even though I know
how -- I tend to think it is better to only use in utility type
programs, not production applications.

Doug
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