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From: =?Windows-1252?Q?Terje_Sletteb=F8?= <tslettebo@chello.no.nospam>
Newsgroups: comp.lang.ada,comp.lang.c++.moderated
Subject: Re: C bug of the day
Date: 14 Jun 2003 16:27:33 -0400
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Date: 2003-06-14T16:27:33-04:00
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"Ron Natalie" <ron@sensor.com> wrote in message
news:Fn2dnUzrDqr3YXSjXTWQlg@giganews.com...
>
> "Terje Sletteb" <tslettebo@chello.no.nospam> wrote in message
news:WXiGa.11515$KF1.273500@amstwist00...
>  > > > I am sorry. I misunderstood. I thought you were being
sarcastic.
>  > > If your suggestion was adopted, how would it affect existing
>  > > programs? For that matter, why would you ever *want*
uninitialized
>  > > variables?
>  >
>  > Reading from streams is an obvious example:
>  >
>  > int i;
>  >
>  > stream >> i;
>  >
>  > Intialising "i" beforehand would just be vasteful.
>
> It wouldn't break anything, just make it a tiny bit slower.   If you
allowed something to inidicate
> uninitialized, you could get the performance back.
>
>      int i;                // initialize to 0
>      stream >> i;
>
>      auto int i;        // recycle auto to mean uninitialized.
>      stream >> i;
>
> In the above case existing code that used the unqualified name would
work in old and new compilers
> (with a slight performance hit in the new complier), those in the
second case would work the same way
> in the old and new compiler (the same way it used to).

"auto" has already been suggested reused for the type inference
proposal. :) ("Decltype and auto"
(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1478.pdf)).
However, that may not clash in this case.

Anyway, this may be a QoI issue. A compiler could warn if an
uninitialised variable is read from, and they typically do.


Regards,

Terje

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