i going through apple's documentation , saw (void (^)(void)). can explain statement means? ^ xor, right? void xor void doesn't makes sense me?
there (void (^)(bool finished))
these blocks add anonymous functions , function objects objective-c. see e.g. introducing blocks , grand central dispatch :
block objects (informally, “blocks”) extension c, objective-c , c++, make easy programmers define self-contained units of work. blocks similar — far more powerful — traditional function pointers. key differences are:
- blocks can defined inline, “anonymous functions.”
- blocks capture read-only copies of local variables, similar “closures” in other languages
declaring block variable:
void (^my_block)(void); assigning block object it:
my_block = ^(void){ printf("hello world\n"); }; invoking it:
my_block(); // prints “hello world\n” accepting block argument:
- (void)dosomething:(void (^)(void))block; using method inline block:
[obj dosomething:^(void){ printf("block called"); }]; 