C++ static member variable of type enum won't compile -

i'm trying write class public enum, , private static member variable of enum type. can initialise value of static variable, if try access in class member function, code won't link. here's simple working example compile with:

g++ -o testclass.o testclass.cpp  

but fails when try compile/link main source file with:

g++ -o test testclass.o testmain.cpp  

the error is:

undefined symbols architecture x86_64:   "testclass::_enum", referenced from:       testclass::printenum()     in testclass.o ld: symbol(s) not found architecture x86_64 

i'm using mac running osx 10.7.5, gcc 4.2.1.

testclass.h:

#ifndef test_class_h #define test_class_h  class testclass { public:   testclass() {};     void printenum();    typedef enum {a, b, c} myenum;  private:   static myenum _enum;   };  #endif 

testclass.cpp:

#include "testclass.h"  #include <iostream> using namespace std;  testclass::myenum _enum = testclass::a;  void testclass::printenum() {   cout << "value of enum: " << _enum << endl; } 

testmain.cpp:

#include "testclass.h"  int main() {   testclass tc;    tc.printenum(); } 

the code below declares file local variable _enum of type testclass::myenum. not providing definition static member variable.

testclass::myenum _enum = testclass::a; 

to that, have define in appropriate class scope, this:

testclass::myenum testclass::_enum = testclass::a;