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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.lang.c
Subject: Re: ANSI C and function prototypes
Message-ID: <6370@utzoo.UUCP>
Date: Thu, 6-Feb-86 16:25:30 EST
Article-I.D.: utzoo.6370
Posted: Thu Feb  6 16:25:30 1986
Date-Received: Thu, 6-Feb-86 16:25:30 EST
References: <681@harvard.UUCP>
Organization: U of Toronto Zoology
Lines: 16

>   ...Is there any way to prototype the second argument as a pointer to
> a function returning 'anything'?  I realize if I prototype the second
> argument as a 'void *pointer', any pointer will be properly converted, 
> but this defeats my purpose of checking to make sure that the second
> argument is really a function pointer...

Prototyping it as "void *" is wrong too, and a strict ANSI-compliant
compiler will reject use of it as illegal.  "void *" is a generic *data*
pointer, and function pointers are not data pointers.  The ANSI drafts
say that mixing function pointers and data pointers is illegal, period,
although it is listed in the relevant appendix as a "common extension".
It certainly is a potential portability problem even if the compiler
permits it.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry