Not that I necessarily think it'd avoid the problem even then, but I wouldn't call this modern C++ exactly. For one thing, it's (c) 2002, so written in C++98. And for another, it looks very uh, C-ish (not that uncommon in the C++98 era). In the bad sense of lots of error-prone pointer-based string manipulation, stuff like this:

    if(STR_COMP(s1, p) >= 0)
    {
       do{ ++p; }while(*p);
       ++p;
       if(STR_COMP(s1, p) <= 0)
          return set_->isnot ? next : ++next;
    }