Question

I have a class that I’m using to store some static default variables for a visual experiment I’m creating.

They are not marked as const, because Im using a GUI to tweak them at runtime.
When I log them in the main class ( which calls the static function init on the Defaults class ) – they are valid. But in the constructor of the different class it returns zero.

The output looks like this

"Constants::init() called" // Constants::Heads::MIN_LIFETIME initialized to 1200
preSetup-Log  Constants::Heads::MIN_LIFETIME 1200
PhysicsObject- Constants::Heads::MIN_LIFETIME 0 // Y you zero?
postSetup-Log  Constants::Heads::MIN_LIFETIME 1200

I’m defining the constants like this:

namespace Constants {
    namespace Forces {
        static int MAX_LIFETIME;
        static float GRAVITY_FORCE;
    };
}


static void init() {
    std::cout << "Constants::init()" << std::endl;
    Constants::Forces::GRAVITY_FORCE = 40000.0f;
    Constants::Forces::MAX_LIFETIME = 3000;
}

Answer 1

// header.h
namespace Constants {
    namespace Forces {
    extern int MAX_LIFETIME;
    extern float GRAVITY_FORCE;
    }
}

// my_constants.cpp
namespace Constants {
    namespace Forces {
        int MAX_LIFETIME = 3000;
        float GRAVITY_FORCE = 40000.0f;
     }
}

Then include header.h in a file that uses the constants. The constants will be initialized automatically when the program starts.