$ perl -e 'use Fcntl; require "Fcntl";'
Can't locate Fcntl in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5) at -e line 1.
$ perl -e 'use Fcntl; require Fcntl;'
$