Qt 5 C++ undefined reference to Class::function(QString, Qstring, ...) -

i know question has been answered in forum before, need more specific help.

here's code:

sessionwindow.cpp

#include "sessionwindow.h"  #include "ui_sessionwindow.h"  #include "session.h"  #include "utils.h"    #include <qstringlist>    sessionwindow::sessionwindow(qwidget *parent) : qdialog(parent), ui(new ui::sessionwindow)  {      ui->setupui(this);      this->setfixedsize(this->size());  }    sessionwindow::~sessionwindow()  {      delete ui;  }    void sessionwindow::on_cancelbtn_clicked()  {      close();  }    void sessionwindow::on_createbtn_clicked()  {      qstring min = (ui->ismin) ? "min" : "nomin";      qstring sp = (ui->sphidd) ? "nosp" : "sp";      qstring name = ui->sessionname->text();      qstring user = ui->skuser->text();      qstring pass = ui->skpass->text();      utils u;        u.createsession(name, user, pass, min, sp);  }

utils.h (where function prototype declared)

#ifndef utils_h  #define utils_h    #include <qstring>  #include <qstringlist>      class utils  {  public:      utils();      ~utils();      void startskype(qstring, qstring, qstringlist);      void createsession(qstring , qstring, qstring, qstring, qstring);  };    #endif // utils_h

utils.cpp (where function is)

#include "utils.h"  #include "session.h"    #include <qstring>  #include <qstringlist>  #include <qvector>  #include <qdebug>    qvector<session> sessions;    utils::utils()  {    }    utils::~utils()  {    }    void utils::startskype(qstring user, qstring pass, qstringlist options)  {    }    void createsession(qstring name, qstring user, qstring pass, qstring ismin, qstring sphid)  {      sessions.append(session(name, user, pass, ismin, sphid));  }

the problem tha can't compile it, throws error: undefined reference `utils::createsession(qstring, qstring, qstring, qstring, qstring)'

sorry if explained bad , help!! :d

you forgot put utils:: in front of method definition:

void createsession(qstring name, qstring user, qstring pass, qstring ismin, qstring sphid) {     sessions.append(session(name, user, pass, ismin, sphid)); } 

should be

void utils::createsession(qstring name, qstring user, qstring pass, qstring ismin, qstring sphid) {     sessions.append(session(name, user, pass, ismin, sphid)); }