Re: Is this OK in C++ and C?

[Zbigniew Komarnicki <cblasius@gmail.com>]

On Wednesday 02 of January 2013 05:25:19 Tixy wrote:
> On Tue, 2013-01-01 at 11:41 -0700, Joe Pfeiffer wrote:
> > Looking into it a bit more, I can't find a place where the C99 standard
> > requires *any* warnings.  In particular:
> > 
> >                                           Annex I
> >                                       (informative)
> >                                   Common warnings
> > 1 An implementation may generate warnings in many situations, none of which are
> >   specified as part of this International Standard. The following are a few of the more
> >   common situations.
> > 
> >   (a list of warnings follows)
> > 
> > A search doesn't turn up the string "warn" anywhere in the standard
> > except in this annex.
> 
> But it probably has quite a few occurrences of 'diagnostic', the C++
> standard does; and it states that a 'diagnostic message' shall be issued
> if a program breaks the rules of the language except where the standard
> explicitly states no diagnostic is required.
> 
> With regard to the original question of assigning a negative value to an
> unsigned integer, this seems to be allowed and defined behaviour. The
> section on integral conversions has:
> 
>         If the destination type is unsigned, the resulting value is the
>         least unsigned integer congruent to the source integer (modulo 2
>         n where n is the number of bits used to represent the unsigned
>         type). [Note: In a two’s complement representation, this
>         conversion is conceptual and there is no change in the bit
>         pattern (if there is no truncation). ]
>         


Thank you all for your help in understanding my problem.

Best regards,
Zbigniew