[Objective-C] Blocksがややこいのでまとめてみる ref: http://qiita.com/edo_m18/items/a1ee24cd23d3adde51d8

file0.m

void (^blk)(void) { NSLog(@"in block"); };

file1.m

(^blk)() { NSLog(@"in block"); };

file10.m

typedef int (^blk_t)(int);

blk_t func() {
    return ^(int i) { return i * i; };
}

file11.m

int (^func())(int) {
    return ^(int i) { return i * i; };
}

file12.m

int i = 5;

void (^capTest)() = ^{
    printf("%d", i);
};

i = 10;

capTest(); //=> 5になる

file14.txt

clang -rewrite-objc main.m

file2.m

int func(int i) {
    return i + 1;
}

int (*funcptr)(int) = &func;

file3.m

typedef void (^blk_t)(void); //`blk_t`が型となる

file4.m

blk_t blk = ^{ NSLog(@"in block"); };

file5.m

- (void)hogeMethod:(void (^)(NSString *str))blk
{
    NSString *test = @"argument";
    blk(test);
}

file6.m

// [Blockの型]には`void (^)(NSString *str)`が入る
- (void)hogeMethod:([Blockの型])blk
{
    //
}

file7.m

void (^anyBlk)(int) = ^void (int i) {
    printf("%d", i);
}

anyBlk(10);

file8.m

void (^)(int i) = …

file9.m

void (^anyBlk)(int i) = ^void (int i) ...

sample.cpp

struct __block_impl {
  void *isa;
  int Flags;
  int Reserved;
  void *FuncPtr;
};

struct __main_block_impl_0 {
  struct __block_impl impl;
  struct __main_block_desc_0* Desc;
  __Block_byref_i_0 *i; // by ref
  __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_i_0 *_i, int flags=0) : i(_i->__forwarding) {
    impl.isa = &_NSConcreteStackBlock;
    impl.Flags = flags;
    impl.FuncPtr = fp;
    Desc = desc;
  }
};