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Subject: Re: Upgrading from a bad C compiler
Date: Sat, 28 Jul 2012 12:41:01 +0200
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On 27.07.2012 22:09, Rod Pemberton wrote:

> I didn't know that, but I avoid sizeof().

Frankly, that's a pretty silly position.

> One could definately argue C shouldn't "know" anything about the padding,
> i.e., it can be argued that padding is outside of C's "sphere of knowledge".

Whether or not that argument can possibly make sense depends on what you 
mean by "C" here: the C source code, the C translation tools, or some 
combination of the two?

Yes, C source code must not know such things all by itself.  But the C 
tools obviously must know (or they couldn't support structs at all). 
But sometimes the C source needs a way to inquire the info from the C 
tools, e.g. to dynamically allocate (arrays of) structs.   The sizeof() 
operator is this way.

> Either way, I see sizeof() leading to problems.

You got that backwards.  sizeof() is what solves those problems.

The actual problem is with people who believe they know better than the 
C compiler what the actual size of a particular data structure must be, 
and therefore come here (and elsewhere) to complain that their 
compiler's sizeof() were buggy.

> There will be those who want to know the exact underlying size of the
> aligned and padded struct so they can allocate space for more aligned and
> padded structs correctly.

Those people have understood what sizeof() is for.

> There will also be those who only want to know only the size of the struct's
> C components so that when they copy the structs C elements to an array or
> other object they don't have extra space included, etc.

Such people have to sum the sizes of individual elements themselves.