Fcntl
(void)Fcntl (lock_fd, F_SETLK, &l);
# define CLOSE_ON_EXEC(fd) (void) Fcntl(fd, F_SETFD, 1)
#define TURN_OFF(X,F) (void)Fcntl(X, F_SETFL, (Fcntl(X, F_GETFL, 0) & ~(F)))
if (strcmp(device, "/dev/null") && Fcntl(fd, F_SETLKW, &lck) < 0) {
if (Fcntl(fd, F_SETLK, &l) == -1) {
Fcntl (i, F_GETFL) < 0 &&
if (Fcntl(fd, F_SETLK, &lock) != -1 || errno != EAGAIN)
#define TURN_OFF(X,F) (void)Fcntl(X, F_SETFL, (Fcntl(X, F_GETFL, 0) & ~(F)))
#define TURN_ON(X,F) (void)Fcntl(X, F_SETFL, (Fcntl(X, F_GETFL, 0)|(F)))