linux tty with canonical mode turned off - non blocking getchar()

cm_test.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>


void cm_off(void)
{
	struct termios t;
	tcgetattr(STDIN_FILENO, &t);
	t.c_lflag &= ~ICANON; 
	t.c_lflag &= ~ECHO;

	// Apply the new settings
	tcsetattr(STDIN_FILENO, TCSANOW, &t); 
}

void cm_on(void)
{
	struct termios t;
	tcgetattr(STDIN_FILENO, &t);
	t.c_lflag |= ICANON; 
	t.c_lflag |= ECHO;

	// Apply the new settings
	tcsetattr(STDIN_FILENO, TCSANOW, &t); 
}

int main(int argc, char const *argv[])
{
	cm_off();
	while (1) {
		printf("%02x\n", (unsigned char)getchar());
		usleep(300000);
	}
	cm_on();

	return 0;
}