Question

I’m assuming this warning is crashing my app. I’m using objective-c for an iOS app. Xcode doesn’t give a stack trace or anything. Not helpful.

I have this assignment as a global variable:

int search_positions[4][6][2] = {{{0,-2},{0,1},{1,-1},{-1,-1},{1,0},{-1,0}}, //UP
    {{-2,0},{1,0},{-1,1},{-1,-1},{0,1},{0,-1}}, //LEFT
    {{0,2},{0,-1},{1,1},{-1,1},{1,0},{-1,0}}, //DOWN
    {{2,0},{-1,0},{1,1},{1,-1},{0,1},{0,-1}} //RIGHT 
};

Wouldn’t search_positions therefore be a pointer to a pointer to an integer pointer?

Why does this give “Initialisation from incompatible pointer”?

int ** these_search_positions = search_positions[current_orientation];

Surely this just takes a pointer to an integer pointer from the array, offseted by current_orientation?

What I am missing here? I thought I knew pointers by now. 🙁

Thank you.

Answer 1

search_positions[current_orientation] is not of type int**; it is of type int[6][2]. search_positions is not a pointer; it is an array.

A pointer to search_positions[current_orientation], would be of type int(*)[6][2] if you take the address of the array:

int (*these_search_positions)[6][2] = &search_positions[current_orientation];

or of type int(*)[2] if you don’t take the address of the array and instead let the array-to-pointer conversion to take place:

int (*these_search_positions)[2] = search_positions[current_orientation];