+the real operation and test for its success - think in terms of atomic
+operations. Filetests are more useful for filesystem administrative
+tasks, when you have no need for the content of the elements on disk.
+
+=head2 The "access" sub-pragma
+
+UNIX and POSIX systems provide an abstract access() operating system call,
+which should be used to query the read, write, and execute rights. This
+function hides various distinct approaches in additional operating system
+specific security features, like Access Control Lists (ACLs)
+
+The extended filetest functionality is used by Perl only when the argument
+of the operators is a filename, not when it is a filehandle.
+
+=head2 Limitation with regard to C<_>
+
+Because access() does not invoke stat() (at least not in a way visible
+to Perl), B<the stat result cache "_" is not set>. This means that the
+outcome of the following two tests is different. The first has the stat
+bits of C</etc/passwd> in C<_>, and in the second case this still
+contains the bits of C</etc>.
+
+ { -d '/etc';
+ -w '/etc/passwd';
+ print -f _ ? 'Yes' : 'No'; # Yes
+ }
+
+ { use filetest 'access';
+ -d '/etc';
+ -w '/etc/passwd';
+ print -f _ ? 'Yes' : 'No'; # No
+ }
+
+Of course, unless your OS does not implement access(), in which case the
+pragma is simply ignored. Best not to use C<_> at all in a file where
+the filetest pragma is active!