How do I share a constant between C# and C++ code?

Question

I\'m writing two processes using C# and WCF for one and C++ and WWSAPI for the second. I want to be able to define the address being used for communication between the two

Answer 1

C# and C++ have differing models for constants. Typically, the constant won't even be emitted in the resulting C++ binary -- it's automatically replaced where it is needed most of the time.

Rather than using the constant, make a function which returns the constant, which you can P/Invoke from C#.

Thus,

#include 
const double ACCELERATION_DUE_TO_GRAVITY = 9.8;
int main()
{
     std::cout << "Acceleration due to gravity is: " << 
         ACCELERATION_DUE_TO_GRAVITY;
}

becomes

#include 
extern "C" double AccelerationDueToGravity()
{
    return 9.8;
}
int main()
{
     std::cout << "Acceleration due to gravity is: " << 
         AccelerationDueToGravity();
}

which you should be able to P/Invoke from C#.