There are many applications where I don’t really want to use the usual
windows page print. Instead I want output to go directly to the printer
using
standard print i/o. It’s actually a topic that is hard to find in any
of the
books on Windows, at least I’ve never found anything on it. But to my
surprise
I recently learned that standard (DOS/UNIX) printing is alive and well
underneath windows. All we need to do is open a printer port and print
to it.
If the printer is directly attached to the computer it’s trivial. The
method
for obtaining a printer port when the printer is on the network isn’t
hard
either.
The example below shows how I use the Windows NET USE command to
re-direct
LPT1 to a shared printer on an NT Server. The same technique applies
for
Novell networks with a slightly different syntax.
Try this out by creating a new MFC Form-based project. Put a button on
the
form and attach this code to it. You can actually print with only 3
lines of code:
FILE *fp = fopen("LPT1", "w"); fprintf(fp,"What's up, Doc?n"); fclose(fp);
Instant print gratification!!
While the program is open it hogs the printer port. In my shop that
isn’t a
problem but be aware of the effect on your windows spooled output.
********************************************************* THE CODE ********************************************************* // the headers for the conventional i/o routines #include#include #include using namespace std; // makes string and ofstream // work without std:: qualifier void CLineprtView::OnButton1() { // I could have used a CString instead of the buff[] // but I wanted to show how this is used with lightweight // ATL code and STD library char buff[MAX_BUFF_SIZE]; // My printer is located on another server so I must re-direct the // printer port. If the printer is directly attached this extra step // is not needed. // on my network the printer is published as \GREENhp5annex // All those back-slashes escape the backslash in the path name if (PRINTER_IS_REMOTE) { system("NET USE LPT1 /d"); // free up the port system("net use lpt1 \\green\hp5annex"); } // old fashioned file handle with // old fashioned open of the printer port FILE *ptr = fopen("LPT1","w"); // laser printer setup string sprintf(buff," 33E 33(s0p4102t1b16.66H 33&l1O"); fprintf(ptr,buff); // old fashioned print fprintf(ptr,"Who of late doth make a thimble.n"); fprintf(ptr,"Is a lower bunk a status symbol??n"); // old fashioned close fclose(ptr); // now the same thing with stream io ofstream optr("LPT1", ios::out); string str_text = "Hey Doc, Ain't this a print test from windowsn"; str_text += "with more lines to follow?n"; optr << str_text << endl; optr << "Quiet, wabbit. I'm conversing with my muse!!n"; optr << "That's all folks." << "f" << flush; // add a formfeed // the printer connection is still open so close it optr.close(); // drop the network link if (PRINTER_IS_REMOTE) { system("net use lpt1 /d"); } }
In practice I get printer path information from the registry on each
machine, so the real live code is a little busier than this example, but
not much.