Path: utzoo!utgpu!attcan!uunet!husc6!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Passing types to a subroutine
Message-ID: <8853@smoke.BRL.MIL>
Date: 10 Nov 88 16:59:12 GMT
References: <14457@mimsy.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 22

In article <14457@mimsy.UUCP> sjr@mimsy.UUCP (Stephen J. Roznowski) writes:
>	float	a[100];
>	subroutine(...., a[100], ...);

>	double	a[100];
>	subroutine(...., a[100], ...);

>subroutine(....,array,....)
>[???]	*array;

>How do you pass the knowledge of the array type to the
>subroutine?

You don't.  Types are dealt with at compile time, not run time.
It is in fact possible for a pointer-to-float to be passed
differently than a pointer-to-double.

If you REALLY have to do this, consider casting the arguments
(which should be "a", not "a[100]") to type pointer-to-void or
pointer-to-char, and add another parameter to the subroutine
that can be used to indicate how to "un-cast" the funny
parameter.  The code for this won't be clean..