Path: utzoo!mnetor!uunet!pilchuck!amc!eric
From: eric@amc.UUCP (Eric McRae)
Newsgroups: comp.sys.amiga
Subject: Need help with printer driver PLEASE
Message-ID: <601@amc.UUCP>
Date: 26 Feb 88 07:51:11 GMT
Reply-To: eric@amc.UUCP (Eric McRae)
Organization: Applied Microsystems Corp., Redmond, WA.
Lines: 30
Keywords: DumpRPort, Cancel, Guru

I've written a printer driver for my little Talley Spirit 80.  I could
have used a PD driver but I wanted to learn.  Everything works fine
until I attempt a graphics dump.  I'm using DpaintII which works for
other drivers.  If I cancel the print, I get a visit from the Guru.
I've tracked the problem to the vicinity of my render.c routine.  When
a print is canceled, pd_PWrite returns a non-zero error.  If I return
the error to the printer driver as is recommended in the example code
on Page E-10 of the RKM, I get an instant Guru:

/*business end of Case 2: (status)  Dump Buffer to printer*/
if(error = (*(PD->pd_PWrite))(&(PD->pd_PrintBuf[bufptr]),bytecount))
	return(error);

Notes:
	Everything works fine until I cancel the dump or I let it go to
	the end.  If I can figure out the first problem, I'll probably
be able to figure out why it also crashes after returning the error
from the call to pd_PBothReady.

	I replaced the return(error) above with return(0);  The cancel
was ignored and the dump went complete and crashed as though I hadn't
attempted the cancel.

	Everything else about the driver works fine.  I'm using Manx 3.4B
long ints, large code & data.

Surely, there are still a few people left in this newsgroup who have
actually written printer drivers.  What am I doing wrong?  Please drop
me a line or call.  This is driving me batty because the Gurus
generally trash vd0: