What the block needs to know.

/* what the block wants to master 1> How to define the block variable int (^sumblock) (int, int); void (^myblock) ();  2> How to use block encapsulation code ^ (int a, int b) {return a-a    ;};  ^ () {    NSLog (@ "----------");};  ^ {    NSLog (@ "----------");};  3> block Access outside variable * block inside can access the outside of the variable * By default, the inside block cannot modify the outside local variable * to the local variable plus the __block keyword, this local variable can be modified within the block  4> Use typedef to define the block type typedef int (^myblock) (int, int); You can then use this type of Myblock to define the block variable Myblock block; Myblock B1, B2;  B1 = ^ (int A, int.) {return a-B    ;};  Myblock B3 = ^ (int a, int b) {    * /

What the block needs to know.