[boost] [xpressive] Does '_' match newlines?

I have the following static regex: sregex filename_re = icase("Content-Disposition:") >> -*_ >> "filename=" >> (s2=-+_) >> ';' ; I want the "*_" part to also match newline characters. I didn't see any flag to turn this on or off. Is this on by default? I see boost::xpressive::regex_constants::syntax_option_type::not_dot_newline, but not sure where you would (or wouldn't) specify this. I only recall the ability to specify flags for a regex when you compile a dynamic regex, not a static one. Help is appreciated! --------- Robert Dailey