Output to stdprn Is in Binary (Untranslated) Mode

• The C Run-Time (CRT), included with:
  • Microsoft C for MS-DOS, versions 6.0, 6.0a, and 6.0ax
  • Microsoft C for OS/2, versions 6.0, and 6.0a
  • Microsoft C/C++ for MS-DOS, version 7.0
  • Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, and 1.52

SUMMARY

The 16-bit C start-up code automatically opens five files for a program's use. The "stdprn" file (PRN device) is opened in binary mode, which is important to remember when printing to printers that require a carriage return/line feed combination to end a line (for example, some laser printers). In those cases, you do one of the following:

• Change your output routines to send a CR/LF pair (\n\r).


-or-


• Reopen stdprn in text mode so that the translation is handled by the run-time library.


-or-


• Change the mode of the file to O_TEXT. You must remember to flush the buffer before doing this.

MORE INFORMATION

The following is a code fragment that illustrates each method:

#include <stdio.h>
#include <io.h>
#include <fcntl.h>
void main(void)
{
   FILE *txtprn;
   fprintf(stdprn, "untranslated\n");        // Standard mode
   fprintf(stdprn, "CRLF pair added \n\r");  // Method 1
   txtprn=freopen("PRN", "wt",stdprn);       // Method 2
   fprintf(txtprn, "translated\n");
   fflush(stdprn);                           // Flush the buffer first
   setmode(fileno(stdprn), O_TEXT);          // Method 3
   fprintf(stdprn, "translated\n");
} 

Additional query words: kbinf 5.10 6.00 6.00a 6.00ax 7.00 1.00 1.50

Keywords          : kb16bitonly 
Version           : 
Platform          : 
Issue type        : 

Last Reviewed: July 21, 1999