Date: Sun, 21 Apr 1996 18:27:40 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: kagel AT dg1 DOT bloomberg DOT com
Cc: djgpp AT delorie DOT com
Subject: Re: Help writing to the printer
In-Reply-To: <9604191241.AA04010@quasar.bloomberg.com >
Message-Id: <Pine.SUN.3.91.960421181551.15447D-100000@is>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On Fri, 19 Apr 1996 kagel AT quasar DOT bloomberg DOT com wrote:

> had with piped output, but, it did not.  I am trying to write to the default
> DOS printer (PRN, LPT1) and cannot.  The app's output goes to the DJGPP temp
> directory and never prints.  Anyone have a solution?  Anyone try this?  I'll

There is a bug in the DJGPP v2 library: it defines `stdprn' as using file 
handle 3 and `stdaux' as using handle 4, whereas it should be the other 
way around.  So when you fprintf to stdprn, it actually tries to write to 
the COM1 port, with the obvious results.

To correct this, compile the files `stdprn.c' and `stdaux.c' below and 
put them into your C library, like this:

	gcc -Wall -O3 -c stdprn.c
	gcc -Wall -O3 -c stdaux.c
	ar rvs c:/djgpp/lib/libc.a stdprn.o stdaux.o
	ranlib c:/djgpp/lib/libc.a

and print happily ever after by writing to stdprn.

> In my Borland and other 16bit versions I just wrote to stdprn or opened 
> a file named "PRN" and voila!  Neither solution seems to work.

Opening "PRN" or "LPT1" works for me.  For instance the following program 
really prints:

	#include <stdio.h>
	void main (void)
	{
	  FILE *fprn = fopen ("PRN", "a");

	  fprintf (fprn, "Hello, world!\n\f");
	}

(I add '\f' because some laser printers won't actually eject the paper 
until they see a form-feed--maybe that's your problem?)

-------------- stdprn.c -----------------------------------
/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
#include <stdio.h>
#include <libc/file.h>
#include <libc/stdiohk.h>

FILE __dj_stdprn = {
  0, 0, 0, 0,
  _IOWRT | _IOLBF,
  4
};

------------------------ stdaux.c --------------------------------
/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
#include <stdio.h>
#include <libc/file.h>
#include <libc/stdiohk.h>

FILE __dj_stdaux = {
  0, 0, 0, 0,
  _IORW | _IONBF,
  3
};