Static Members

[Deftwun]

I'm attempting to create a logger class which has a static string vector. This way multiple instances of the logger can add strings to the same shared vector with out the need for pointers to a manager class or something like that..

Heres what I've got so far but I keep getting undefined reference errors:

class Logger{
public:
    //Add String to Vector
    void Log(std::string theString) { mStrings.push_back(theString) }

    //Get String List
    std::string Get() {//Iterate through vector and return all strings as a single string..}

    //String Container
    static std::vector<std::string> mStrings;
};

class Test_A{
public:
    //Do stuff..
    void Foo() { mLogA.Log("Hello ") }

    //Logger instance
    Logger mLogA;
};

class Test_B{
public:
    //Do stuff..
    void Foo() { mLogB.Log("World") }

    //another Logger instance
    Logger mLogB;
};

int Main{
    //and another Logger Instance
    Logger mLogMain;    
    
    //Test Classes
    Test_A myClassA;
    Test_B myClassB;

    //Test Classes do your stuff..
    myClassA.Foo();
    myClassB.Foo();
    
    //output string
    std::string StringList;
    StringList = mLogMain.Get();

    //...String list should now contain "Hello World"
	
}

This is just an example really and probaly wont compile but thats essentially what I'm trying to do.

[shacktar]

static member variables need to be defined outside the class definition. Try putting this after Logger's class definition:

std::vector<std::string> Logger::mStrings;

(And if you're going to put your code in multiple files, then the definition of Logger::mStrings should go in an implementation file)

[Deftwun]

Ah ok. Yeah I came across that solution elsewhere but I kept putting it in the header. Your advice worked perfectly. Thanks shaktar