/*
 * Sample program for fcntl system call - No.55
 *
 * fcntl - manipulate file descriptor
 *
 * Synopsis
 *     #include <unistd.h>
 *     #include <fcntl.h>
 *
 *     int fcntl(int fd, int cmd);
 *     int fcntl(int fd, int cmd, long arg);
 *     int fcntl(int fd, int cmd, struct flock *lock);
 *
 * Description
 *     fcntl performs one of various miscellaneous operations on
 *     fd. The operation in question is determined by cmd:
 *                   ...................
 *     F_GETFL Read the descriptor's flags (all flags (as set by
 *             open(2)) are returned).
 *                   ...................
 *     see 'man fcntl' for more information.
 */

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

#define BYTESIZE 8

void printbits(int flag)
{
        int i;

        for (i = 0; i < BYTESIZE * sizeof(flag); ++i)
                printf("%d", (flag << i & 1 <<
                         BYTESIZE * sizeof(flag) -1) ? 1 : 0);
        putchar('\n');
}

main()
{
	int fd, flag;

	fd = open("fcntl.c", O_RDONLY | O_NONBLOCK);

	flag = fcntl(fd, F_GETFL);
	printf("O_NONBLOCK is set\n");
	printf("flag = ");
	printbits(flag);

	exit(0);
}