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Date: Tue, 24 May 2011 00:19:01 -0400
From: pete <pfiland@mindspring.com>
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Subject: Re: Types in C
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.c:4664

Uncle Steve wrote:
> 
> On Mon, May 23, 2011 at 10:12:02PM -0500, Shao Miller wrote:
 
> > The standard definition in C99, if I'm not mistaken, includes:
> >
> >   "The meaning of a value stored in an
> > object or returned by a function
> > is determined by the /type/ of the expression used to access it..."
> 
> Doesn't that specify when and how a cast occurs in expression
> evaluation?

The quoted text is not about conversions.

If you have a signed char with a value of (-1)
and you convert that by assignment to unsigned char,
then the value in the unsigned char object will be
equal to UCHAR_MAX, on any computer.

    signed char minus_one = -1;
    unsigned char max = minus_one;

That's conversions.

But, if you access minus_one as an unsigned char

    unsigned char access_value = *(unsigned char *)&minus_one;

then the value of access_value may or may not 
be something different from UCHAR_MAX,
depending on the representation of ((signed char)-1).

That's not conversions.

-- 
pete