Nonblocking code in Unix

How to give an input to nonblocking code in unix ? The code is as follows:

#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>

void set_fl(int fd, int flags);

char buf[10];

int main()
{
    int noread;

    set_fl(STDIN_FILENO, O_NONBLOCK); //code for nonblocking
    set_fl(0, O_NONBLOCK);            //code for nonblocking
    noread = read(0, buf, sizeof(buf));

    printf("INPUT: %s\n", buf); 

    return 0;
}

void set_fl(int fd, int flags)
{
    int val;

    if ((val = fcntl(fd, F_GETFL, 0)) < 0)
            printf("ERROR: %s\n", "fcntl F_GETFL error");

    val |= flags;     //changes the bit 

    if (fcntl(fd, F_SETFL, val) < 0)
            printf("ERROR: %s\n", "fcntl F_SETFL error");
}