How to initialize private static members in C++?

Question

What is the best way to initialize a private, static data member in C++? I tried this in my header file, but it gives me weird linker errors:

class foo
{
           


        

Answer 1

One "old-school" way to define constants is to replace them by a enum:

class foo
{
    private:
        enum {i = 0}; // default type = int
        enum: int64_t {HUGE = 1000000000000}; // may specify another type
};

This way doesn't require providing a definition, and avoids making the constant lvalue, which can save you some headaches, e.g. when you accidentally ODR-use it.