Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!decwrl!decvax!ima!cfisun!lakart!dg
From: dg@lakart.UUCP (David Goodenough)
Newsgroups: comp.lang.c
Subject: Re: YALF (yet another lint foulup)
Message-ID: <379@lakart.UUCP>
Date: 3 Jan 89 16:39:39 GMT
References: <9255@smoke.BRL.MIL>
Organization: Lakart Corporation, Newton, MA
Lines: 63

From article <9255@smoke.BRL.MIL>, by gwyn@smoke.BRL.MIL (Doug Gwyn ):
> In article <14672@cisunx.UUCP> cmf@unix.cis.pittsburgh.edu (Carl M. Fongheiser) writes:
>>In article <9228@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>>>Function value type and whether a function returns are orthogonal.
>>Really?  I'm having a good deal of difficulty thinking of any reason why
>>one would declare a function which never returns as anything other than
>>void.
> 
> Where did you get the word "never"?

Probably from the same place I did for the example below

> 	unsigned int Square(unsigned int n)
> 	{	extern void exit(int);
> 		extern void /*also nonreturning*/ Fatal(char*);
> 		if (n >= 0x80)
> 			Fatal("overflow in Square");
> 		return n*n;
> 	}
> 
> This, not entirely implausible, function sometimes returns and
> sometimes doesn't.  But that has nothing to do with its type.

True, but probably irrelevant. What Mr. Fongheiser is referring to is something
like:

void command()
 {
    extern void exit();

    for (;;)
     {
	switch (getchar())
	 {
	    case 'q':
	      exit();
	    /* NOTREACHED */
	    case 'a':
	      a_command();
	    break;

		/* etc. etc. */
	 }
     }
    /* NOTREACHED */
 }

command() can NEVER (repeat NEVER) return. Hence to give it (say) type int
is not sensible, meaningful or anything.

:-) :-) smiley mode on :-) :-)
What is in fact needed is ANOTHER function type notreturning, as opposed
to void, because in one way void implies return, it also however imples
return without a corresponding return value. notreturning imples that
a function is a one way thing. lint could be made a lot more sensible
about exit() if such a thing existed, and if we could figure out how to
tell it about for (;;) without breaks, we could do away with
/* NOTREACHED */
-- 
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