Unbufferred file I/O

[Scott "The Pseudo-Hacker" Neugroschl]

In article <2961 at crash.cts.com> cline at pnet01.cts.com (Ben Humphreys) writes:

    [ stuff about how write is buffered, and wants to go unbuffered input ]

Use ioctl().  Set the terminal flags to:

#include <sys/types.h>
#include <sys/ioctl.h>
#include <termio.h>

	struct termio ttyold, ttynew;
		
	/* get the terminal params twice */
	if (ioctl(0,TCGETA,&ttyold) == -1 || ioctl(0,TCGETA,&ttynew) == -1)
	{
		perror("program");
		exit(-1);
	}

	/* set up for unbuffered I/O */
	ttynew.c_cc[VMIN] = 1;
	ttynew.c_cc[VTIME] = 0;
	ttynew.c_lflags &= ~ICANON;
	if (ioctl(0,TCSETAW,&ttynew) == -1)
	{
		perror("program");
		exit(-1);
	}

	/* Stuff to talk to other user here */


	/* clean up when done */
	ioctl(0,TCSETAW,&ttyold);
	exit(0);				/* done */


Note that you should catch SIGINT and probably SIGQUIT too, so that you 
can clean up gracefully before dropping dead.


-- 
Scott "The Pseudo-Hacker" Neugroschl
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