Why is the __block keyword allowed in the interface?

Question

If I try to access the "object variable" with the storage type __block:

@interface { __block float x; } 

in the block:

 @implementation ... { ... -(void) func: { ^(...) { x = 0; } } 

I get a “save loop” warning if I don’t create the __block link for myself and use it like:

 -(void) func: { __block id s = self; ^(...) { s->x = 0; } } 

Why can I declare a variable "__block" in the interface?

Answer 1

__ Block variables live in a repository that is shared between the lexical region of the variable and all blocks and block copies declared or created within the lexical region of the variables. cm.