Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!husc6!bloom-beacon!tut.cis.ohio-state.edu!rutgers!att!alberta!lake
From: lake@alberta.UUCP (Robert Lake)
Newsgroups: comp.sys.ibm.pc
Subject: Determining if a printer is available
Message-ID: <2165@pembina.UUCP>
Date: 26 Mar 89 22:01:19 GMT
Organization: U. of Alberta, Edmonton, AB
Lines: 30

I am trying to determine if a line printer is attached to my PC.  I am
using the Lattice C (Version 3.0) compiler and I have code similar to the
following:

#include <stdio.h>

main()
{
	FILE *prdev;
	if ((prdev = fopen("prn", "w")) == NULL) {
		printf("Cannot open line printer\n");
		exit(1);
	}
	fprintf(prdev, "This is a test\n");
	...
}

The problem with the above is that the fopen always succeeds, even if there
is no printer attached to my PC.  Is there a Lattice C subroutine I have
missed which can determine if a printer is attached and on-line?  Or what
must I do to determine this myself?

I have tried using onerror(), but this will suppress the DOS error messages
only after I have tried to write data to the printer.  I would like to print
a suitable error message before I write any data.

Thanks in advance for any advice and suggestions.

						Rob Lake (alberta!lake)
						University of Alberta