Re: generalized lvalues

[Robert McNulty Junior <bobbymcn@bellsouth.net>]

Michael Matz wrote:

>Hi,
>
>On Thu, 18 Nov 2004, Matt Austern wrote:
>
>  
>
>>But I'll give two examples (details changed partly to protect the guilty and
>>partly because I'm doing this by memory):
>>(1) #define foo(x) *(a, b, x)
>>(2) ((long*) p)++
>>    
>>
>
>Actually, from my experience looking at assorted packages which are tried
>to be build with 4.0, the latter use is most common.  I.e. casting a
>pointer to some type to implicitely specify how much it is incremented.  
>Some software is very much known for using such constructs (wine, rpm,
>elfutils, dietlibs, many others) .  I even tend to say, that such usage is
>well defined (within certain limits), although I admit that it's not ISO
>C99.
>
><rant>
>All the whining about how unspecified this is, and how the writer of the
>code deserve to be bitten, is just language lawyer masturbation (which I
>also very much enjoy when closing bugreports about this or that compiler
>bug with INVALID), but it doesn't change the fact, that there are quite
>some packages out there actually using such extensions.  This 
>cast-as-lvalue extension removal is one of the bigger items which result 
>in much work for package maintainers (not so much for C++, as there anyway 
>this extension wasn't used much).
></rant>
>
>So, if anyone wants to bring it back, with defined semantics of course
>(like for instance memory accessed through a casted pointer is well
>defined (not outside the memory for the object accessed), and only for C)  
>I'm all ears.
>
>
>Ciao,
>Michael.
>
>  
>
Micheal, GCC 4.0 looks cool. I have the latest CVS. 
http://www.geocities.com/bobbymcn2004 will take you to a site of music 
that was made with a program using GCC 4.0.
Under Cygwin.
All my latest music is there. This is my dream. You guys have done it. 
GCC has come a long way since  I started with you four years ago with 
GCC 3.0. I'm using Cygwin. One problem. The songs are encoded in Windows 
Media Encoder, so you need a player that plays wma files.
There's not that many. And yes, that's me playing the piano. Neat.
GCC 4.0, when its released will be appreciated by all.