How to define an array of strings of characters in header file?

Question

I have many different 3 axis sensors I am writing test code for. In the C files for each of them, I have the same char string defined:

char axis[3][8] = {\"X\",          


        

Answer 1

If you must put it in a header file, use extern or static:

// option 1
// .h
extern char axis[3][8];

// .c
char axis[3][8] = { "X", "Y", "Z" };

// option 2
// .h
static char axis[3][8] = { "X", "Y", "Z" };

Extern tells the linker that there is a global variable named axis defined in one of our implementation files (i.e. in one .c file), and I need to reference that here.

static, on the other hand, tells the compiler the opposite: I need to be able to see and use this variable, but don't export it to the linker, so it can't be referenced by extern or cause naming conflicts.