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From: dave@cs.arizona.edu (Dave P. Schaumann)
Newsgroups: comp.lang.c
Subject: Re: Expressions in initializers
Message-ID: <1043@caslon.cs.arizona.edu>
Date: 5 Mar 91 23:00:48 GMT
References: <17270@crdgw1.crd.ge.com> <760@ajpo.sei.cmu.edu> 
 <1991Mar4.144939.8311@ux1.cso.uiuc.edu> <1032@caslon.cs.arizona.edu> <3599.27d3ca8a@iccgcc.decnet.ab.com>
Organization: U of Arizona CS Dept, Tucson
Lines: 33

In article <3599.27d3ca8a@iccgcc.decnet.ab.com> browns@iccgcc.decnet.ab.com (Stan Brown) writes:
|In article <1032@caslon.cs.arizona.edu>, dave@cs.arizona.edu (Dave P. Schaumann) writes:
|| First thing you need to realize is that there is no special, pre-defined
|| function sqrt() in C.  [more embarassing comments deleted :-/ ]

|This was my thought at first, and it's certainly true for non-ANSI compilers.
|
|But App. F.2 of the ANSI standard says undefined behavior results "if the 
|program redefines a reserved external identifier (4.1.2)."
|[...]
|So 'sqrt' is a reserved identifier with external linkage, and behavior
|is undefined if the user redefined the 'sqrt' identifier by providing
|her own sqqrt function.

Ok, ok, OK!!!  I was wrong.  I know it now.  I spoke from experience with
the pre-standard C.  I guess I really need to take a close look at K&R2 to
see what other suprises are lurking for me there...

That aside, the logical conclusion of "constant" evaluation at compile-time
will make C compiler into a C interpreter as well.  I have been reminded in
the past that C is supposed to be a small language (when wishing for a
largest-of operator on enums).  Think how much more work the compiler must
do to evaluate constant-parameter functions at compile time, even if you
limited this to standard library functions.

Can you say "creeping featurism?"  Can you say "kitchen sink?"
Sure!  I knew you could...

-- 
		Dave Schaumann		dave@cs.arizona.edu
'Dog Gang'!  Where do they get off calling us the 'Dog Gang'?  I'm beginning to
think the party's over.  I'm beginning to think maybe we don't need a dog.  Or
maybe we need a *new* dog.  Or maybe we need a *cat*! - Amazing Stories