All of the following comments apply to the newly release Boost-1.33
*Multiline*
multiline is on by default. To turn it off either: 1) prefix your expression with (?-m) 2) compile your expression with the flag no_mod_m set: boost::regex r("^abc", boost::regex::perl | boost::regex::no_mod_m); 3) Pass the "match_single_line" flag to one of the matching/searching algorithms/iterators.
*ExplicitCapture*
Named captures aren't supported.
*Singleline*
This is on by default, you can turn it off by either: 1) Prefix your expression with (?-s) 2) Compile the expression with the flag no_mod_s set: boost::regex r("^abc", boost::regex::perl | boost::regex::no_mod_s); 3) Pass " match_not_dot_newline" flag to one of the matching/searching algorithms/iterators.
*IgnorePatternWhitespace*
Is this the same as Perl's x-modifier? If so then either: 1) Prefix your expression with (?x) 2) Compile your expression with the flag mod_x set: boost::regex r("^abc", boost::regex::perl | boost::regex::mod_x); John.