Fail if the lock cannot be acquired within _seconds_. Decimal fractional values are allowed. See the *-E* option for the exit status used. The zero number of _seconds_ is interpreted as *--nonblock*.
*--fcntl*::
-Instead of flock(2), apply an fcntl(2) open file description lock (that is, using the F_OFD_SETLK (non-blocking) or F_OFD_SETLKW (blocking) commands). These locks are independent of those applied via flock(2), but, unlike traditional POSIX fcntl() locks (F_SETLK, F_SETLKW), have semantics matching those of flock(2).
+Instead of *flock*(2), apply an *fcntl*(2) open file description lock (that is, using the *F_OFD_SETLK* (non-blocking) or *F_OFD_SETLKW* (blocking) commands). These locks are independent of those applied via *flock*(2), but, unlike traditional POSIX fcntl() locks (*F_SETLK*, *F_SETLKW*), have semantics matching those of *flock*(2).
+
This is only available on kernel versions >= 3.15.