Unbuffered I/O using MicroSoft C 3.0

[Tom Reingold]

In article <1867 at sunybcs.UUCP>, ugwayne at sunybcs (Wayne Nelligan) writes:
> 
>     A friend of mine recently asked me "If I knew of a program that would let
> your printer act like a typewriter?".  Since a program of this sort seemed 
> really easy to write (just get characters and send them to the printer), I
> decided I would just write one myself.  Well, I am sorry to say, things have
> not been as easy as I thought they would be.  The problem is that I can't get
> the printer to just print one character at a time.  It only prints out a line
> at a time.
> [...]
>     So what I would like to know then, Is how would I get a program like
> this to work?  How do you get unbuffered I/O using MicroSoft C 3.0?
> What am I doing wrong?  If anyone has any suggestions, I
> would sure appreciate a response.  This is really driving me crazy.   
> 
>                              Thanks in advance,
>                                    Wayne

You are probably automatically generating unbuffered output but the printer
buffers its input until a line is full.  A line is full either when it gets
a CR or when its length is reached.  You can fool it with the method
outlined in the enclosed program.

Good luck.

Tom
========================================================================
#include <stdio.h>

#define   CR      '\r'
#define   LF      '\n'
#define   TAB     '\t'
#define   SPACE   ' '

/* 
 * This is an example program.  It reads the standard input
 * and prints it to the standard printer, one character
 * at a time.  Tabs and other subtle things will not work 
 * because it is an example to show you that you can do
 * what you want to.
 *
 * The printer prints when the line length is reached or
 * when it gets a RETURN character.  This program sends one
 * after each character.
 *
 */

main()
{
    char line[256];
    int i, j;

    while ((gets(line)) != NULL) {
        for (i=0; i < strlen(line); i++) {
            fputc(line[i], stdprn);
            fputc(CR, stdprn);
            fputc(SPACE, stdprn);
            for (j=0; j < i; j++)
                fputc(SPACE, stdprn);
        }
        fputc(LF, stdprn);
    }
}
-- 
Tom Reingold;  The Rockefeller University; 1230 York Av; NY 10021
PHONE: (212) 570-7709 [office]; (212) 304-2504 [home]
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