Easy way to remove extension from a filename?

This works:

std::string remove_extension(const std::string& filename) {
    size_t lastdot = filename.find_last_of(".");
    if (lastdot == std::string::npos) return filename;
    return filename.substr(0, lastdot); 
}

size_t lastindex = fullname.find_last_of("."); 
string rawname = fullname.substr(0, lastindex); 

Beware of the case when there is no "." and it returns npos