SV may be any of a CV, a GV, a reference to a CV, a reference to a GV
or C<SvPV(sv)> will be used as the name of the sub to call.
SV may be any of a CV, a GV, a reference to a CV, a reference to a GV
or C<SvPV(sv)> will be used as the name of the sub to call.