c++ - unresolved overloaded function type -

i'm trying write templated class holds reference object of it's template parameter type, , pointer void returning no arg member function of class. i'm getting error '<unresolved function type>' when compile.

template<class t> class memberaction { public:     memberaction(void (t::*func)() , t& object); private:     void (t::*m_func)();     t& m_object; };  template<class t> memberaction<t>::memberaction(void (t::*func)() , t& object) {     m_func = func;     m_object = object; }  class file { public:     file();     void telunus_open();      //memberaction<file>& getopenaction();  private:     memberaction<file> m_openaction; };  file::file():         m_openaction(telunus_open,*this)//line error on {  }  void file::open() {      // } 

compiling g++ 4.7.2 following error message:

stackoverloaderrorexample.cpp|31|error: no matching function call 'memberaction<file>::memberaction(<unresolved overloaded function type>, file&)'| 

it seems other people similar compiler error confusing pointers global functions pointers member functions, declare constructor taking pointer member function of it's template parameter, , pass member function of correct type.

so how resolve compiler error?

i believe need pass &file::telunus_open—or &file::open, whichever name you’ve called it—to member function pointer. open has function type void (file::)() whereas &file::open has type want, function pointer type void (file::*)(). beyond that, you’re going have issues m_object reference member. assignment operator try assign uninitialised reference:

template<class t> memberaction<t>::memberaction(void (t::*func)() , t& object) {     m_func = func;     m_object = object; } 

you should use constructor initializer list instead:

template<class t> memberaction<t>::memberaction(void (t::*func)() , t& object)   : m_func(func),     m_object(object) {}