- file-lock PORT #!optional SHAREDprocedure
Locks the file associated with PORT using an "exclusive" lock (see flock(2) for more information on shared vs exclusive locks). If SHARED is given and true, then a shared lock will be requested. Returns #t if requesting the lock succeeded or #f otherwise.
PORT may be a file port or a file-descriptor.
NOTE: On native Windows builds (all except cygwin), this procedure is unimplemented and will raise an error.