NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/std/c/391

Internet Message Format | 1996-08-06 | 2KB

Path: solon.com!not-for-mail
From: Dominic Feeley <[e-mail]>
Newsgroups: comp.std.c,comp.lang.c.moderated
Subject: Re: Integral promotion.
Date: 14 Feb 1996 21:25:15 -0600
Organization: DF Designs
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In article <4fstj7$[e-mail]>
           [e-mail] "Rune Huseby" writes:

> I got a problem understanding the rules on integral promotion in
> the C language:
>
> short test(short x1, short x2);
>
> My compiler (Microsoft Visual C++ 4.0), automagically converts
> my short-parameters to int's, even though all variables involved
> are short. I know that the standard says that all arguments can
> be converted to the biggest 'type' of all the arguments, but is
> it correct that char's and short's always are promoted to int's,
> without regard to the other arguments in the expression?

This is news to me, but it seems that section 6.2.1.5 of the standard
says that the lowest integer type is an int. If I am going to buy these
things I suppose I ought to read them.

My reading is that
short result = x1 + x2; /* going from int to short, possible loss of data */

gives the "same" result mathematically as
short result = ( int ) x1 + ( int ) x2 ;
i.e. you assign an int to a short value. The results of this conversion
are ( I think ) implementation-defined if the short is signed.

Regards,
Dominic.

--
Dominic Feeley