use warnings;
sub RO { warn "RO" }
sub SHAM { warn "SHAM" }
RO();
{ local *RO = sub { warn "BO" }; RO(); }
SHAM();
{ local *SHAM; *SHAM = sub { warn "BO" }; SHAM(); }
RO(); SHAM();
__END__
RO at - line 2.
Subroutine main::RO redefined at - line 5.
BO at - line 5.
SHAM at - line 3.
BO at - line 7.
RO at - line 2.
SHAM at - line 3.