gistfile1.h

#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>

int main() {
  int fd[2];
  int r = pipe(fd);
  if (getsockopt(fd[0], SOL_SOCKET, 0, NULL,NULL) == ENOTSOCK) {
    printf ("Woohoo!\n");
  } else {
    printf ("Oh noes\n");
  }
}