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From: diamond@tkou02.enet.dec.com (diamond@tkovoa)
Newsgroups: comp.sys.mips
Subject: Re: mips cc "shortcoming" with compile time array initializtion.
Message-ID: <1771@tkou02.enet.dec.com>
Date: 6 Jun 90 01:20:36 GMT
References: <21901@boulder.Colorado.EDU>
Reply-To: diamond@tkou02.enet.dec.com (diamond@tkovoa)
Organization: Digital Equipment Corporation Japan , Tokyo
Lines: 30

In article <21901@boulder.Colorado.EDU> hartzell@beagle (George Hartzell) writes:

>   ccom: Error: moose.c, line 8: constant expected
>         static int ia[] = {  ((char *) &X.a - (char *) &X),  ((char *)
>   X.b - (cha
>   r *) &X),  ((char *) &X.c - (char *) &X) } ;
>         --------------------------------------------------^
>I have two questions:
>    a) should this be legal [in the ansi sense?, in the practical
>       sense?] (The compiler should have all the info it needs to
>       figure this out, shouldn't it?) 
>    b) do the 2.10 compilers support this construction?

Well, here are your two answers:
a)  no, it's subjective, and yes.
b)  I don't know.
but who's counting?

It is not legal in ANSI.
Whether it should be accepted practically is a matter of opinion.
    I personally think that it should be accepted with an optional warning.
I think that the compiler has enough information to figure it out.
    Other compilers certainly prove that it is possible.
I have seen rumors that MIPS, and perhaps DEC, are aware that competitors
    can handle this case.  But if I were privileged enough to know their
    plans, I would not be allowed to tell you.

-- 
Norman Diamond, Nihon DEC     diamond@tkou02.enet.dec.com
Proposed group comp.networks.load-reduction:  send your "yes" vote to /dev/null.