C++ :: How Many Times Is A Const Variable Initialized

I hope I got all the jargon correct. I have something like this:

Code:

const Fl_Color my_fl_dark_gray=fl_color_cube(64*(FL_NUM_RED-1)/255, 64*(FL_NUM_GREEN-1)/255, 64*(FL_NUM_BLUE-1)/255);

in a header file and the header file is included in several C files.

Questions:

At run time,

Is there just one copy of the const variable my_fl_dark_gray or are there multiple copies for the multiple C files?If a function uses the const variable, does the initialization statement "my_fl_dark_gray=fl_color_cube(...);" run every time the function is called or does it just run once and then when the function is called it just uses the value stored in memory?