/* Test opening of a file with O_DIRECT */

#include <asm/types.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/types.h>
#include <asm/fcntl.h>  /* Note: <fcntl.h> DOES NOT HAVE O_DIRECT! */
                        /* <fcntl.h> is a glibc header... */
#include <errno.h>
#include <stdio.h>

int main(void) {
    char message[] = "Welcome to the winter of my discontent.\n";
    int fd = open("testopen.txt", O_RDWR|O_CREAT|O_SYNC|O_DIRECT, S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR);
    int len;
    if(fd < 0) {
        printf("Unable to open file, errno is %d.\n", errno);
    } else {
        printf("Got fd %d.\n", fd);
        if((len = write(fd, message, strlen(message))) < 0) {
            printf("Unable to write to file, len is %d, errno is %d.\n", len, errno);
        } else {
            printf("%d bytes written to file.\n", len);
        }
    }
    close(fd);
    printf("End of program...\n");
    return 0;
}