why does program stop print spooler?

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4 total messages Started by Joel Swank Tue, 09 Sep 1986 18:32

#7865

Author: Joel Swank
Date: Tue, 09 Sep 1986 18:32

9 lines
770 bytes

I have a C program that stops the print spooler ( the PRINT command).
I cannot figure out what is causing this. The spooler stops printing
whin this program is in control, and resumes normally when it exits.
Any Ideas?

Thanks,
Joel Swank
Tektronix, Redmond, Oregon

Re: why does program stop print spooler?

#7873

Author: SCHEUTZOW,MICHAEL J
Date: Thu, 11 Sep 1986 19:28

14 lines
1140 bytes

>
>I have a C program that stops the print spooler ( the PRINT command).
>The spooler stops printing
>whin this program is in control, and resumes normally when it exits.
>
Does the C-program grab interrupt 28h?  I believe that PRINT uses this
interrupt to achieve a pseudo-form of multitasking.  When the machine
is waiting around for you to type something, it ocassionally calls int
int 28h when it is safe to do so.  See Best of BIX in the Sept issue
of BYTE.

Mike Scheutzow         Trek trivia: In what state was Kirk born?
Georgia Tech
gt6294b@gitpyr.uucp

Re: why does program stop print spooler?

#7590

Author: bobm
Date: Fri, 12 Sep 1986 17:21

11 lines
1077 bytes

	The PRINT command works by taking over an interrupt called the 
	'DOS IDLE' hook (Int 28H). This hook is called by DOS whenever 
	it is in an idle state, such as waiting for keyboard input. Every
	time int 28 is called, PRINT dumps a burst of characters to the 
	printer. If you have a program that doesn't do many DOS I/O calls,
	Int 28 will not be called, and the spooler won't have a chance 
	to run until you exit to DOS.

	Bob May
	hplabs!hp-pcd!bobm

Re: why does program stop print spooler?

#7909

Author: Henry Perkins
Date: Mon, 15 Sep 1986 20:10

19 lines
1480 bytes

> >I have a C program that stops the print spooler ( the PRINT command).
> >The spooler stops printing
> >whin this program is in control, and resumes normally when it exits.
> >
> Does the C-program grab interrupt 28h?  I believe that PRINT uses this
> interrupt to achieve a pseudo-form of multitasking.  When the machine
> is waiting around for you to type something, it ocassionally calls int
> int 28h when it is safe to do so.  See Best of BIX in the Sept issue
> of BYTE.
> 
More accurately, MSDOS raises INT 28H when it's in a keyboard input wait.
If the C program isn't doing keyboard input, or if the C doesn't use
MSDOS calls to read from the keyboard, you'd expect printing to stop.
This is why I have a HARDWARE print buffer.
-- 
{hplabs,amdahl,3comvax,okstate}!bnrmtv!perkins        --Henry Perkins

It is better never to have been born.  But who among us has such luck?
One in a million, perhaps.

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