Re: Overlay allowability

["Marc A. Criley" <marc.a.criley@lmco.com>]

Okay, if there's a simple answer to this I'm going to look really dumb
for asking...but I'll take that chance :-)

My goal has been to serialize an arbitrary object (the type of which is
provided as a generic formal parameter) into a Stream_Element_Array for
use with the AdaSockets package.

I've been all over the RM95 looking for a nice, clean way to do this,
and have not been able to find one.  It appears then to come down to
working with Unchecked_Conversion or the 'Address overlay approach (the
latter of which was provided as the example in my original posting).

If there's a straightforward way to accomplish what I'm _really_ trying
to do, I would very much like to hear it!  And performance does matter,
since I want to minimize socket blocking.

Oh, and to forestall the "Why not use the DSA?" question, the answer is
that the required post-processing associated with GLADE just won't fly
with clients, so I need to use the basic client/server model.

Marc A. Criley


Ted Dennison wrote:
> 
> In article <39184D91.13BA15B4@Raytheon.com>,
>   "Samuel T. Harris" <samuel_t_harris@Raytheon.com> wrote:
> 
> > problems across compiler implementations. It is rare that
> > such interfacing code deals with unconstrainted arrays
> > or polymorphic variant records. Usually just run-of-the-mill
> > scalars, static records, and constrainted arrays.
> 
> The typical use I've seen of it (UC-ing addresses into object pointers)
> is in converting random data objects into arays of bytes. Since the base
> type for one side is typically an unconstrained array of bytes, I think
> this is quite likely to be an issue.
> 
> Usually this is done to convert some nice user data structure into
> something an entity outside of Ada (such as an OS call) can deal with.
> Just about any other use is going to be a hack around a badly-chosen
> type. Thus the Right Thing would be to redesign the type.
> 
> --
> T.E.D.
> 
> http://www.telepath.com/~dennison/Ted/TED.html
> 
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> Before you buy.