$ perl -e  '@c=readdir DIR ; print "@c\n";'

##</code><code>##

$ perl -w -e  '@c=readdir DIR ; print "@c\n";'
Name "main::DIR" used only once: possible typo at -e line 1.
readdir() attempted on invalid dirhandle DIR at -e line 1.

##</code><code>##

$ perl -e  '@c=readdir DIR or print "$!"; print "@c\n";'
Bad file descriptor