How to declare extern 2d-array in header?

Question

We have this declaration in LCD.c:

unsigned char LCD[8][64] = {((unsigned char) 0)};

And in LCD.h we want to have something like:

extern unsigned char LCD[][];

We get this error:

Error[Pe098]: an array may not have elements of this type

Answer 1

You need, at a minimum, to include the right-most column size for a 2-D array. You can declare it like this:

extern unsigned char LCD[][64];

Otherwise the compiler would not be able to compute the offset after the first row.