有自动变量，且有__block存储域类说明符：
struct __Block_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; // by ref
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_val_0 *_val, int flags=0) : val(_val->__forwarding) {
impl.isa = &_NSConcretesStackBlock;
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; // bound by ref
(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((void *)&dst->val, (void*)src->val, 8/*BLOCK_FIELD_IS_BYREF*/);}
static void __main_block_dispose_0(struct __main_block_impl_0 *src){_Block_object_dispose((void*)src->val, 8/*BLOCK_FIELD_IS_BYREF*/);}
static struct __main_block_desc_0 {
size_t reserved;
size_t 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 ()
{
__attribute __((__blocks__(byref)))__Block_byref_val_0 val = {(void*)0, (__Block_byref_val_0*)&val, 0, sizeof(__Block_byref_val_0), 0};
void (*blk)(void) = (((void(*)())&__main_block_impl_0((void*)__main_block_func_0, &__main_block_desc_0_DATA,(__Block_byref_val_0*)&val,570425344));
((void(*)(__block_impl*))((__block_imp *)blk)->FuncPtr)((__block_impl*)blk);
return 0;
}