st_nlink field being zero (which is
otherwise always forced to be at least one) and all the other fields of
the stat buffer having unspecified contents.
+The path should be absolute and must not end in a slash. If it is +relative and your working directory changes, the behaviour is undefined.
Since there is no standard to do this, the portable implementation simply
calls stat (2) regularly on the path to see if it changed somehow. You
can specify a recommended polling interval for this case. If you specify