tokenizing a string made of "only" seperator characters

Hi All,

Following function utilizing boost's string tokenizer class crashes as might be expected:

Code:

---

bool CheckCommand(const string& cmd, const string& line)
{
        if (line.length() == 0)
                return false;

        typedef tokenizer< char_separator<char> > StrTokenizer;
        char_separator<char> sep(":");
        StrTokenizer tokens(line, sep);
        StrTokenizer::iterator it = tokens.begin();

        if (*it == cmd) { <<<<--------------- Crash takes place at this line
            ++it;
            if (it != tokens.end()) {
                return true;
        }
    }

        return false;
}

---

when line is "::::::::::::::::::::", i.e. made of merely separator characters (":").

How can I check

Code:

---

StrTokenizer::iterator it

---

actually points to something meaningful to prevent this crash ?

Thanks.

Code:

---

if ( it != tokens.end() && *it == cmd )

---

bye!