warnings::warnif "Can't opendir($dir_name): $!\n";

##</code><code>##

P:\test>perl -Mstrict -wl
opendir D, 'c://System Volume Information' or warn $!,$/, 'OS reports:', $^E;
print while $_=readdir(D);
close D;
^Z
Invalid argument
OS reports:Access is denied at - line 1.

##</code><code>##

P:\test>perl -MFile::Find -Mstrict -wl
{
        local $^W;
        find( sub{ print; }, 'c:/System Volume Information' );
}
^Z
.