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4.1 Changes
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re: ID Changes
Scott Atwell / American Century <>
5 Feb 1998 3:47PM ETWe've had some good discussion on this topic. Note that we cannot change the data type for existing, released versions of the spec. It is imperative from a compatibility standpoint that one does not send alphabetic characters for ExecID in 2.7, 3.0, or 4.0. We must also recognize that people will begin implementing such changes at different times.
> Mark Hinman wrote:
>
> > The problem with with changing the data types instead of creating a new data fields is maintaining multiple simultaneous FIX connections across different versions of the spec. Global search and replace sounds easy but it kill backwards compatiblity with other FIX connections. We currently are supporting concurrent connections to FIX 2.7, 3.0 and 4.0. and we intend to continue full backwards compatiblity.
>
> Andrew Wilson wrote:
> > >
> > > Our implimentation will require less work to change the id data types to char than to add the extra code to handle the new ids to the many apps that use the engine.
> > >
>
> I agree with Andrew (and not Mark). We currently support
> FIX 3.0 and 4.0 concurrently, and 4.1 will be much easier
> to support concurrently if we just generalize the types of
> the ID fields from int to char. I could understand the need
> for new fields if the new type conflicted with the old one.
> But, in this case, the new type is more general; it is a
> superset of the old type. Thus, if everyone generalizes
> his/her code to treat these fields as type char, then the
> new code will work with all versions. Why isn't that
> the simplest approach to take? If we create new fields,
> then we will still have to write the code to support
> handling these fields as type char, but we will also have
> to add a layer of indirection that will allow us to map
> the field to the appropriate implementation field based
> on the version number. Just generalizing the type will
> enable us to avoid that layer of indirection.
>
> So please just generalize the data type to char. Don't
> bother to add all those new fields.
>
> Andrew Schorr
> Daiwa Securities America Inc.
> schorr@ead.dsa.com
>
>
re: ID Changes
Scott Atwell / American Century 5 Feb 1998 3:47PM ET
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