Path: utzoo!attcan!uunet!cs.utexas.edu!csd4.milw.wisc.edu!srcsip!tcnet!pwcs!stag!root
From: dynasoft!john@stag.UUCP (John Stanley)
Newsgroups: comp.sys.atari.st
Subject: Re: Wanted:  How to tell if drive B is REALLY attached?
Message-ID: <1989Jul17.001544.19108@stag.UUCP>
Date: 17 Jul 89 00:15:44 GMT
Sender: root@stag.UUCP (Computer Abuser)
Organization: Mindtools ST Access Group
Lines: 45

Newsgroups: comp.sys.atari.st

[jeff@quark.WV.TEK.COM (Jeff Beadles) writes...]
> 
> The title pretty well tells it all.  I need to know if drive B is attached.
> The functions that I've seen thus far always report two drives, and want the
> user to swap.
> 
> I would prefer a "legal" way to do this so my application will work under any
> of the various TOS's.

  The following (in C since Jeff didn't specify otherwise) should work
with any existing TOS.  I've carefully written this so it "should" also
work under any version of C that runs on the ST.  The only limitation is
that you must have the osbind.h header file available for the version of
C you use (or some other way to access the Super() function...)...:

#include <osbind.h>

nflop()  /* Returns actual number of floppy drives connected.  */
	 /* (Returns:  0 = -none-,  1 = A:,  and 2 = A: + B: ) */
	{
	register char *ssp;
	register int cnt;

	ssp = (char*)Super(0L);		/* enter super mode */

	cnt = *(unsigned char*)0x04a7;	/* get value from system variable */

	(void)Super(ssp);		/* return to user mode */

	return(cnt);
	}

  Note:  The system variable is actualy a two byte word based at $4a6,
but I addressed it as an unsigned char to make the code portable across
all the various 16bit and 32bit integer versions of C that are available
on the ST.  This doesn't work for most variable bu does here because
there are only 3 possible legal values in this system variable.

	... John STanley

---
John Stanley <dynasoft!john@stag.UUCP>
Software Consultant / Dynasoft Systems