generalized lvalues -- patch outline

[Matt Austern]

On Nov 22, 2004, at 1:39 PM, Joe Buck wrote:

> On Mon, Nov 22, 2004 at 01:23:22PM -0800, Matt Austern wrote:
>> Unfortunately, there is another reason for allowing some tamed version
>> of assignment to casts: compatibility with other compilers.  Microsoft
>> and CodeWarrior both allow this in one form or another.  (Microsoft 
>> for
>> C only, CodeWarrior for C++ as well.  CodeWarrior only allows some
>> limited forms of assignments to casts, and doesn't treat a cast as a
>> true lvalue, so they still get overload resolution right.)
>
> Does CodeWarrior document the semantics of their extension?

I'm trying to find  that out.  It's taking me a while, I'm afraid, 
partly because I'm not all that familiar with their documentation. I 
agree that's an important question.  Another important question that I 
don't know the answer to: are there other compilers that accept some 
form of this extension?  I wouldn't be surprised; lots of people have 
MS-compatibility modes.

One oddity I've found is that CW allows this:
   int x;
   int* p = x;
   char c;
   (char*) p = &c;

but not this:
   int x;
   (char) x = 'a';

And, as I said, they do choose the correct overload when you pass 
((char*) p) to a function that's overloaded on char*& and  char* 
const&.

			--Matt