Question

Been a loooooong time since I’ve actually coded straight c (not even C++ but c) and I know how to use the extern keyword to share a variable between separate .c files, but what I can’t remember is how to share constant data between files?

For example, say I have this… (note, this is not c code (or if it is, its an accident) but rather pseudo-code to show what I want):

const char const * WEEKDAYS[] = {
    "Sunday",
    "Monday", 
    "Tuesday"
}

Now I’m trying to create an array of char pointers that point to the data. Again, this is constant data so I’d like to just define it in a header directly, but that’s where I can’t figure out how to do it, or if that isn’t how you should do it anyway and you should still declare it in the c file, then use extern in the header you include elsewhere.

Again, been a long time since I’ve had to deal with this thanks to the newer, more modern languages, but hoping you can help.

Answer 1

It’s the same as for variables:

// header
extern const char * const WEEKDAYS[3];

// implementation
const char * const WEEKDAYS[3] = {
    "Sunday",
    "Monday",
    "Tuesday"
};

Also you probably want const char * const, not const char const * which is invalid syntax.