Can ofstream be used for printing on a printer

Question

Can ofstream be used to write on a printer?

eg:

string nameOfPrinter = "xyz";
ofstream onPrinter(nameOfPrinter);
onPrinter << "Printing.... ";

If I do as above will I get the output by the printer (on the paper) ?

If not, why I won't get the output? Please suggest a way to print using a printer.

I am targeting the Windows platform (32bit)

Don't forget that `ofstream` doesn't have a constructor that takes `std::string`! — Lightness Races in Orbit, Jul 01 '11 at 09:14
http://www.codeproject.com/KB/printing/lineprint.aspx?print=true — Lightness Races in Orbit, Jul 01 '11 at 09:15
@Tomalak: unless you have a c++0x capable Standard library :) — rubenvb, Jul 01 '11 at 09:21

score 4 · Answer 1 · answered Jul 01 '11 at 09:24

4

If you happen to have your printer associated with LPT1 and a printer which support formfeeds.

#include <iostream>
#include <fstream>
using namespace std;

int main ()
{
    ofstream printer ("LPT1");
    if(!printer)
    {  return 1;
    }

    printer.puts("Test Test Test\n");
    printer.putc('\f');
    printer.close();
    return 0;
}

LPT1 is also a file name in windows. But as known it is a reserved filename. So it will not be possible to have more than one file with the name LPT1. And this file is already managed by windows.

See for reserved filenames

answered Jul 01 '11 at 09:24

fyr

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Writing to LPT1 is not a proper way to print on Windows, and is unlikely to work. – Cat Plus Plus Jul 01 '11 at 09:29
1

Given the requirements stated at the top it will probably. – fyr Jul 01 '11 at 09:30
If you go back in time, probably. – Cat Plus Plus Jul 01 '11 at 09:32
Thats not the point the question was "can ofstream be used for printing" and thats in my understanding a valid answer to it. – fyr Jul 01 '11 at 09:39
@ fyr When i try to execute the file , message is **MSVCP100D.dll** _missing.Try re-installing the program_ – Suhail Gupta Jul 05 '11 at 09:05
There is a stackoverflow topic regarding this error: http://stackoverflow.com/questions/4668566/application-has-failed-to-start-because-msvcp100d-dll-was-not-found-reinstalling – fyr Jul 05 '11 at 09:24

Alok Save · Answer 2 · 2011-07-01T10:18:17.187

3

Yes you can, Your code should be:

ofstream printer;
printer.open("lpt1");

I believe it's case sensitive(not sure "lpt1" or "LPT1"). Also, you'll need to write a page eject command.

EDIT:
LPT (Line Print Terminal) is name of the parallel port interface on IBM PC-compatible computers. Over the years, the parallel port interface has decreased use because of the rise of Universal Serial Bus.

In DOS, the parallel ports could be accessed directly on the command line. For example, the command type c:\autoexec.bat > LPT1 would direct the contents of the autoexec.bat file to the printer port(recognized by the reserved word LPT1"). A PRN device was also available as an alias for LPT1.

Microsoft Windows still refers to the ports in this manner in many cases, though this is often fairly hidden.

In the Linux operating system the first LPT port is available via the filesystem as /dev/lp0.

To write to a printer, one should simply open the printer as if it were a file (the printer name is system-dependent; on Windows machines, it will be lpt1 or prn, while on unix machines, it will be something like /dev/lp), then write whatever text has to be written.

Sample program could be as simple as:

std::ofstream print; 
print.open("LPT1");
if (!print)
    return 0;
print << data;
print.close();

edited Jul 01 '11 at 10:18

answered Jul 01 '11 at 09:10

Alok Save

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Huh? "lpt1" is a filename, last I checked. – Lightness Races in Orbit Jul 01 '11 at 09:11
@Tomalak Geret'kal: Everything is a file in Unix/Linux. – Alok Save Jul 01 '11 at 09:13
1

OK, and what does that have to do with Windows? – Lightness Races in Orbit Jul 01 '11 at 09:14
(Even on Unix/Linux, you can't just open a file "lpt1" and expect it to work. It would be in some device path like "/dev/lpt1".) – Lightness Races in Orbit Jul 01 '11 at 09:15
1

@TomalakGeret'kal: It's one of reserved DOS device names, you cannot create a file named like this. – Cat Plus Plus Jul 01 '11 at 09:16
2

@CatPlusPlus: Hah, so it is! That's amazing! OK I'll remove the downvote but this answer _definitely_ needs fleshing out. And Unix/Linux still has nothing to do with it. – Lightness Races in Orbit Jul 01 '11 at 09:17
In any case, writing to LPTx or PRN is not guaranteed to work. – Cat Plus Plus Jul 01 '11 at 09:21
@ Als When i try to execute the file , message is **MSVCP100D.dll** _missing.Try re-installing the program_ (I compiled in my pc and ran it somewhere else) [code which became a binary code](http://suhail03.my3gb.com/printc++.txt) – Suhail Gupta Jul 05 '11 at 09:07

Nicol Bolas · Answer 3 · 2011-07-01T09:56:39.387

2

How would the file stream know the difference between the name of a printer and a file that just happened to share the name of a printer? So no; you can't print to a printer by specifying the name of a printer.

Printing in Win32 is not a trivial task. You can't simply shove some characters at a printer; it needs to know about page layout, fonts, etc. Basically, the way to do it from Win32 is to "draw" to the printer with GDI commands. Beginner-level info can be found here.

Correction: apparently, you can stream output to the printer with a stream. However, it requires that the user has enabled some legacy functionality, so it isn't necessarily always available.

edited Jul 01 '11 at 09:56

answered Jul 01 '11 at 09:10

Nicol Bolas

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[Printing reference on MSDN](http://msdn.microsoft.com/en-us/library/ff686805%28v=VS.85%29.aspx). – Cat Plus Plus Jul 01 '11 at 09:23
-1 ... you cant have certain filenames twice in windows. See the reference to reserved filenames in my answer. – fyr Jul 01 '11 at 09:27
@fyr: Fair enough. But it's still not a good way to write to a file, since as you point out, it isn't guaranteed to actually work. – Nicol Bolas Jul 01 '11 at 09:58

Can ofstream be used for printing on a printer

3 Answers3