vern@2006-10-19:/var% ls tags

regex_replace

p. #include
#include
#include

int main() {
    boost::regex reg("(Colo)(u)(r)", regbase::extended | regbase::icase);

    std::string s="Colour, colours, color, colourize";
    s=boost::regex_replace(s,reg,"$1$3");
    std::cout << s;
}

g++ test.cpp -lboost_regex

./a.out

Color, colors, color, colorize