【Objective-C高级编程】iOS与OS X多线程和内存管理(六) __block 说明符

int global_val = 1;
static int static_global_val= 2;

int main ()
{ 
     static int static_val =3;
     void (^blk)(void) = ^{
          global_val *= 1;
          static_global_val *= 2;
          static_val *=3;
     };

     return 0;
}

__block int val = 1;
void (^blk)(void) = ^{ val = 1; };

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

struct __main_byref_val_0 {
     void *__isa;
     __Block_byref_val_0 *__forwarding;
     int __flags;
     int __size;
     int val;
};

struct __main_block_impl_0 {
    struct __block_impl impl;
    struct __main_block_desc_0 *Desc;
     __Block_byref_val_0 *val;   

    __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_val_0 *val, int flags = 0):val(i_val->__forwarding) {
        impl.isa = &_NSConcreteStackBlock;
        impl.Flags = flags;
        impl.FuncPtr = fp;
        Desc = desc;
    }
};

static void __main_block_func_0 (struct __main_block_impl_0 *__cself) {
     __Block_byref_val_0 *val = __cself ->val;
     val->__forwarding->val = 1;
}

static void __main_block_copy_0 (struct __main_block_impl_0 *dst, struct __main_block_impl_0 *src)
{
     _Block_object_assign (&dst->val, src->val, BLOCK_FIELD_IS_BYREF);
}

static void __main_block_dispose_0(struct __main_block_imp1_0 *src)
{     
     _Block_object_dispose(src->val, BLOCK_FIELD_IS_BYREF);
}

static struct __main_block_desc_0 {
    unsigned long reserved;
    unsigned long Block_size;
     void (*copy)(struct __main_block_impl_0 *, struct __main_block_impl_0 *);
     void (*dispose)(struct __main_block_impl_0*);
} __main_block_desc_0_DATA = {
    0,
    sizeof(struct __main_block_impl_0),
     __main_block_copy_0;
     __main_block_dispose_0;
};

int main()
{
     __Block_byref_val_0 val ={0, &val, 0, sizeof(__Block_byref_val_0), 10};
     static int static_val = 3;
     blk = & __main_block_impl_0(__main_block_func_0, &__main_block_desc_0_DATA, &val, 0x22000000);
    
    return 0;
}