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From: Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>
Newsgroups: comp.lang.ada
Subject: Re: Last stream problem: byte order
Date: 28 Mar 2002 13:34:24 -0500
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"Eric G. Miller" <egm2@jps-nospam.net> writes:

> > It depends on how clever the compiler is. If the compiler optimizes the
> > static expression in the following if-statement away then it is indeed a
> > compile time check. Otherwise it is a run-time check.
> > 
> >       if System.Default_Bit_Order = System.Low_Order_First then
> >          ... (swap the bytes)
> >       else
> >          ... (don't swap the bytes)
> >       end if;
> > 
> > But I don't think this makes a big difference in either case.
> 
> GNAT gives a warning that the condition is always true (or false).
> Don't know if it eliminates the unreachable branch (I would think so
> with -02). Resorting to preprocessing trickery would probably insure
> it is always a compile time check. Don't know if there's another
> way...

You can have two package bodies, one for Low_Order_First, one for
High_Order_First. Choose which body you use at compile time by setting
paths (in gnat, this is done in gnat.adc via pragma Source_Name).

-- 
-- Stephe