Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mitel!sce!cognos!dy4!paul
From: paul@dy4.uucp (Paul Burry)
Newsgroups: comp.lang.c
Subject: Were GNU C extensions proposed for the standard?
Keywords: ANSI, GNU, typeof, inline, alignof
Message-ID: <153@dy4.UUCP>
Date: 16 Jan 90 19:27:41 GMT
Reply-To: paul@dy4.UUCP (Paul Burry)
Organization: DY-4 Systems Inc. Nepean, Ont Can.
Lines: 62


	While we're on the subject of useful extensions to C
(like "typeof"), I was wondering if any of the other GNU C
extensions were proposed as new features in ANSI C.

	Some of GNU C's more useful extensions (IMHO) are:

o	the addition of the "typeof" keyword

o	the addition of the "inline" keyword

o	the addition of the "alignof" keyword

o	statements and declarations inside of expressions
	ie.
	    #define max(a,b)		\
		({			\
		    int _a = (a);	\
		    int _b = (b);	\
		    _a > _b ? _a : _b;	\
	        })
	(on a side note, why didn't ANSI C define a way to avoid
	shadowing external variables in a macro defining?)

o	generalized lvalues 
	ie.
	    allowing expressions, compound expressions and casts as lvalues.

o	arrays of zero length

o	arrays of variable length
	ie.
	    some_function(int n)
            {
		char array[n];
		    :
	    }

o	non-constant initializers allowed for aggregates
	ie.
	    foo(float f, float g)
	    {
		float array[2] = { f-g, f+g };
	    	    :
	    }

o	application of volatile and const to functions
	ie.
	    volatile functions do not return (like exit(), abort()).
	    const functions produce no side effects (like sin()).

There are a number of other extensions, but I think that these are the
most useful.

If these extensions were proposed, what was the justification for denying
their inclusion in the standard?

-- 
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Paul Burry 			PHONE:  (613)-596-9911
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