Declaration differences between C and C++ const

When you declare a variable as const in the C source code file, you can do this by:

const int i = 2;

You can then use this variable in another module, as follows:

extern const int i;

However, to get the same behavior as in C++, the const variable must be declared as:

extern const int i = 2;

If you want to declare the extern variable for the C source file in the C++ source file, use:

extern "C" const int x = 10;

To prevent name renormalization by the C++ compiler.