Why do nil / NULL blocks cause bus errors when run?

Question

I started using blocks a lot and soon noticed that nil blocks cause bus errors:

typedef void (^SimpleBlock)(void);
SimpleBlock aBlock = nil;
aBlock(); // bus         


        

Answer 1

Caveat: I'm no expert in Blocks.

Blocks are objective-c objects but calling a block is not a message, although you could still try [block retain]ing a nil block or other messages.

Hopefully, that (and the links) helps.