Bock Basic Knowledge

Blocks is an extension of the C language, with an anonymous function with automatic variables. C function pointer type variable vs Block type variable  

C function pointer type variable	Block type variable
return value type method name parameter list expression int func (int count) {return count + 1;}	^ return value type parameter list expression ^int (int count) {return count+1;}
Declares a function pointer type variable int (*funcptr) (int);	Declares a block type variable int (^blk) (int);
Assigns the defined function address to the function pointer type variable int (*funcptr) (int) = &func;	Use the block syntax to assign a block to the block type variable int (^blk) (int) = ^int (int count) {return count+1;};

The complete block syntax differs from the general C-language function definition by only two points: (1) No function name (2) with "^" using block type variables in function parameters and return values for comparison of descriptions  

Do not want TypeDef to declare block type	Use typedef to declare block type typedef int (^blk_t) (int);
void func (int (^blk) (int)) {}	void func (blk_t blk) {}
Int (^func ()) (int) {return ^int (int count) {return count+1;};}	blk_t func () {blk_t blk = ^int (int count) {return count+1;}; return BLK;}

Bock Basic Knowledge