Fsync in a newly created folder?

Can anyone explain why fsync can return EINVAL when I pass in a folder descriptor in it? There is my code, it's pretty simple:

#include <dirent.h>     /* Defines DT_* constants */
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <errno.h>


#define handle_error(msg) \
do { trace(msg); exit(0); } while (0)
#define trace printf


int createDir(const char* name) {
    int r = ::mkdir( name, 0777 );
    if (r != 0) {
        trace("error r!=0 %d\n",errno);
    }
    r = open(name, O_RDONLY | O_DIRECTORY);
    if (r < 0) {
        trace("error create dir r <0\n");
    }
    return r;
}

int main(int argc, const char * argv[]) {

    int r;

    int dir = createDir("test");

    r = fsync(dir);
    trace("r = %d %d\n",r,errno);
    close(dir);


    return 0;
}

      

        
        
        
      

    

it gives me this result:

r = -1 22

      

        
        
        
      

    

I am using linux ver. 2.6.32 (Ubuntu 10.04 as far as I remember)

So why did I get an error when I call fsync on a folder? When I call fsync with the passed file descriptor everything is fine