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From: rajiv@ur-valhalla.UUCP (Rajiv Arora)
Newsgroups: comp.sys.mac
Subject: Re: Aztec 'C' problem - help!
Message-ID: <866@ur-valhalla.UUCP>
Date: Wed, 26-Nov-86 12:22:24 EST
Article-I.D.: ur-valha.866
Posted: Wed Nov 26 12:22:24 1986
Date-Received: Wed, 26-Nov-86 21:12:25 EST
References: <864@ur-valhalla.UUCP>
Reply-To: rajiv@ur-valhalla.UUCP (Rajiv Arora)
Distribution: net
Organization: EE VLSI Graduate Research Facility, UR, Rochester NY
Lines: 58
Keywords: Errors in the sample program

In article <864@ur-valhalla.UUCP> I write:
>
>Hi all.
>
>I have a question for those of you who have used the Appletalk Manager
>calls from Aztec 'C'. I'm trying to use the AB Link Access Protocol in
>my application and can't for the life of me get the function
>LAPOpenProtocol () to work. I was wondering if any of you had had the
>same problem and knew of a fix. Shown below is the code illustrating
>the problem: 
>
>   [Buggy Program]

Here is the corrected code (sorry 'bout that):
#include <stdio.h>
#include <appletalk.h>
#include <syserr.h>

main ()
{
OSErr errcode;
pascal OSErr MPPopen ();
pascal OSErr LAPOpenProtocol ();
ABByte myLAPType;			/* ABByte is typedefed as
					   "unsigned char" and Ptr as
				           "char *" in appletalk.h */
Ptr myprotoptr;				   
if ((errcode = MPPOpen ()) != noErr)
    {
    printf ("error opening MPP\n");
    printf ("errorcode = %d\n", errcode);
    }
else
    {
    myLAPType = 53;		/* arbitrary protocol number */
    myprotoptr = NULL;
    if ((errcode = LAPOpenProtocol (myLAPType, myprotoptr)) != noErr)
	{
	printf ("error opening protocol\n");
	printf ("errorcode = %d\n", errcode);
	}
    }
}

The problem is that LAPOpenProtocol always returns with errorcode -94,
which indicates that either myLAPType (= 53) is out of range, already
present in the protocol handler table, or that the protocol table is
full. Since the table can have upto 4 entries, and only two are used
by DDP (i.e. LAP types 1 and 2), the last should not be the case. The
other two possibilities also seem unlikely.

Any suggestions/comments/help would be greatly appreciated.

Rajiv Arora
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