Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!pilchuck!amc-gw!sigma!flash!bill
From: bill@flash.UUCP (William Swan)
Newsgroups: comp.os.minix
Subject: Re: float VS double: The return...
Message-ID: <643@flash.UUCP>
Date: 11 Apr 90 21:38:03 GMT
References: <16383@nigel.udel.EDU>
Reply-To: bill@flash.UUCP (William Swan)
Organization: The Baidarka Historical Society
Lines: 43

In article <16383@nigel.udel.EDU> ARCHER@segin4.segin.fr writes:
>CvW> ... WHAT ABOUT
>CvW> test(a) float a;
>CvW> {
>CvW> test1(&a);
>CvW> }
>CvW> This certainly passes a pointer to a double, and this can't be changed.
>CvW> So I ask the C Syntax experts - what do you think a compiler should do
>CvW> in both cases?

I've come a little late into this discussion, and I'm no C Syntax Expert[tm],
but I've run into this before.  Oddly, this came up on a local BBS this past
weekend.

The description of the ANSI C standard in K&R 2nd Ed. says, in essence, that
float parameters declared "old-style" are promoted to double, those declared
"new-style" are not.  (K&R C, 2nd Ed. ,p 202, section A7.3.2 Function Calls)  

In other words:
	main() {
		float f; 
		test(&f);
		}
	test(f)
	float *pf; 
		{
		printf(..., *pf);
		}
will fail, but:
	main() {
		float f; 
		test(&f);
		}
	test(float *pf) {
		printf(..., *pf);
		}
will not.

-- 
Bill Swan      bill@Summation.WA.COM          Send postal address for info:
	Innocent but in prison in Washington State for 13.5 years (or more):
	Ms. Debbie Runyan: incarcerated 01/1989, scheduled release 07/2002.
	                   In now:  1 year,   2 months,  3 weeks,  1 day.