Date: Mon, 27 Feb 1995 09:04:36 -0500
From: kagel AT quasar DOT bloomberg DOT com
To: jkeene AT unlinfo DOT unl DOT edu
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Question reagarding kbhit()
Reply-To: kagel AT ts1 DOT bloomberg DOT com

   Errors-To: postmaster AT ts1
   From: jkeene AT unlinfo DOT unl DOT edu (Jon Keene)
   Date: Mon, 27 Feb 1995 00:33:38 -0600 (CST)
   X-Mailer: ELM [version 2.4 PL20]
   Content-Type: text
   Content-Length: 581


   Could anyone tell me why it is that when I run the following
   program, it pauses for the keyboard hit _before_ doing any output?

   Ponderously yours,
   Rumball
   ---

   #include <stdio.h>
   #include <pc.h>
   #define BUFSIZE 1840  /* (80 * 23) */
   #define BLANK ' '

   main () {

	   int i;
	   int buf[BUFSIZE];

	   for ( i = 0; i < BUFSIZE; i++ )
		   buf[i] = BLANK;
	   buf[0] = 'a';
	   buf[BUFSIZE - 1] = 'z';
	   for ( i = 0; i < BUFSIZE; i++ )
		   printf("%c", buf[i]);
	   while (!kbhit()) 
		   ;
	   return 0;
   }


   -- 

The output function, printf(), writes to stdout which is a buffered file.  You
either must write to stderr, using fprintf( stderr, ... ), or call
fflush( stdout ) before calling kbhit().

Thus:

#include <stdio.h>
#include <pc.h>
#define BUFSIZE 1840  /* (80 * 23) */
#define BLANK ' '

main () {

   int i;
   int buf[BUFSIZE];

   for ( i = 0; i < BUFSIZE; i++ )
	   buf[i] = BLANK;
   buf[0] = 'a';
   buf[BUFSIZE - 1] = 'z';
   for ( i = 0; i < BUFSIZE; i++ )
	   printf("%c", buf[i]);
   fflush( stdout );
   while (!kbhit()) 
	   ;
   return 0;
}

-- 
Art S. Kagel, kagel AT ts1 DOT bloomberg DOT com