Create a pointer to two-dimensional array

Question

I need a pointer to a static 2-dimensional array. How is this done?

static uint8_t l_matrix[10][20];

void test(){
   uint8_t **matrix_ptr = l_matrix; //wron         


        

Answer 1

In C99 (supported by clang and gcc) there's an obscure syntax for passing multi-dimensional arrays to functions by reference:

int l_matrix[10][20];

void test(int matrix_ptr[static 10][20]) {
}

int main(void) {
    test(l_matrix);
}

Unlike a plain pointer, this hints about array size, theoretically allowing compiler to warn about passing too-small array and spot obvious out of bounds access.

Sadly, it doesn't fix sizeof() and compilers don't seem to use that information yet, so it remains a curiosity.