Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!convex!texsun!newstop!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: AmigaDOS help...
Message-ID: <126319@sun.Eng.Sun.COM>
Date: 13 Oct 89 21:41:05 GMT
References: <1484@nigel.udel.EDU>
Sender: news@sun.Eng.Sun.COM
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Organization: Sun Microsystems, Mountain View
Lines: 52

In article <1484@nigel.udel.EDU> new@udel.edu (Darren New) writes:
>I'm trying to get the name of the device ("DF0:") given the name of
>the volume ("Empty"). ...
>  ...  AmigaDOS obviously does this somehow, but I don't know how.
>Can somebody give me a clue?    -- Darren

A Clue :

#include <libraries/dosextens.h>
#include <libraries/filehandler.h>

	struct FileLock *fl;
	long		lock;
	struct DeviceList *dl;
	struct DeviceNode *dn;
	char	DeviceName[80];
	struct MsgPort	*ourtask;
	
	lock = Lock("Empty:");
	if (!lock) 
		/* No mounted device has an empty volume in it,
		   NOTE: This will generate a requester "please put
	 	   Empty: in any drive." 
		 */
	fl = (struct FileLock *)BADDR(lock);
	dl = (struct DeviceList*)BADDR(fl->fl_Volume);
	ourtask = dl->dl_Task;

	/* Now this works, but I don't know if CBM will guarantee it
	   to continue to work. DeviceNodes are always added to the
	   head of the list. So your volume node will always be in
	   front of the device node for the device it is mounted on.
 	*/

	Forbid(); /* Watch out for changes */
	for (dn = (struct DeviceNode *)(BADDR(dl->dl_Next)); dn;
		dn = (struct DeviceNode *)(BADDR(dn->dn_Next))) {
		if (dn->dn_Type != DLT_DEVICE)
			continue;
		if (dn->dn_Task == ourtask) {
			strcpy(DeviceName, (char *)(BADDR(dn->dn_Name))+1);
			break;
		}
	}
	Permit();

	printf("That volume is on device %s. \n", DeviceName);

--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
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