Regex sætning i C++

#include <iostream>

int main() {
  php /www/ext_hosts/kjeldsted.net/test.php;
}

<?
echo "Hello World!";
?>

test.cpp:4: error: 'php' was not declared in this scope

Jan 30 01:58:50 jenskjeldsted proftpd[22996] jenskjeldsted (::ffff:86.48.54.30[::ffff:86.48.54.30]): FTP session opened.
terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string::_S_construct NULL not valid
Aborted

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <stdlib.h>
#include <boost/regex.hpp> 

using namespace boost;
using namespace std;

regex expression(".*(no\\ such\\ user\\ found\\ from).*:(\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}).*");

string wrongUser(string sLine) {
    cmatch what;
    const char* response = sLine.c_str();
    cout << response << endl;
    if(regex_match(response, what, expression)) {
        /*cout << "0: " << what[0] << endl;
        cout << "1: " << what[1] << endl;
        cout << "2: " << what[2] << endl;
        cout << "3: " << what[3] << endl;*/
        return what[2];
    }
    else return 0;
}

int main() {
    vector<string> v;
    string sLine;
    ifstream gadminLog ("/var/log/secure");
    if(gadminLog.is_open()) {
        int iU = 0;
        while(gadminLog.good()) {
            getline (gadminLog,sLine);
            //cout << line << endl;
            v.push_back(sLine);
            iU++;
        }
        gadminLog.close();
    }
    else cout << "Filen kunne ikke åbnes";
   
    //cout << "Hello world!" << endl;

    for(int i=0; i < v.size();i++) {
        string sBuff;
        string sIPBuff;
        if(!v[i].empty()) {
            sBuff = v[i].substr(7,8);
            cout << wrongUser(v[i]) << endl;
            //cout << sBuff << "\t" << v[i] << endl;
            //cout << v[i] << endl;
        }
    }
    cout << "Done!" <<endl;
    return 0;
}

There is an existing bug though that means that accessing the regex as a
string doesn't work (will be fixed in the next release).