Properly defining a static NSString* c-style array under ARC

Question

In my implementation file, I have a static 2-dimensional c-style array of NSString* defined as:

static NSString* TheColorArray[][3] = {
    [RedType] = {@"red", @"blah", @"YES"},
    [BlueType] = {@"blue", @"yadda", @"YES"},
    .....
}

The method in question accesses the array like:

-(NSString*)value:(NSInteger)value {
    return TheColorArray[value][0];
}

This all seems to work fine about 99% of the time...but when it fails to work it always fails with EXC_BAD_ACCESS - KERN_INVALID_ADDRESS at 0x11

I've verified that my value parameter is not beyond the bounds of the array. It seems odd that the address is 0x11...which kind of implies that the array has not been initialized.

So what is happening here? Is there some "gotcha" I need to be aware of with ARC and c-style arrays?

Answer 1

The documentation is clear that structs cannot contain ARC'd objects, we could argue that this applies to multidimensional array datums as well, though it doesn't say so. Did you try this:

static NSString __unsafe_unretained * TheColorArray[][3] = ...

This will take the objects allocated here out of ARC and remove any possibility that the compiler is aggressively nulling where it shouldn't be.

Assuming that's the problem. Maybe if you're able to step back with the debugger, can you see what symbol is being dereferenced when it errs?