iOS开发之Block（3）

tips：-rewrite-objc 选项将源代码编译为C++源代码

首先是c语言源文件中实现block:

#include <stdio.h>int main(int argc, const char * argv[]){    void(^blk)(void) = ^{        printf("Block\n");    };        blk();        return 0;}

编译之后:

//block结构体 （__block_impl的实例）struct __main_block_impl_0 {      struct __block_impl impl;      struct __main_block_desc_0* Desc;      //构造函数  __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int flags=0) {    impl.isa = &_NSConcreteStackBlock;    impl.Flags = flags;    impl.FuncPtr = fp;    Desc = desc;  }};//block变量 带有自动变量的匿名函数 （匿名函数被当作简单c函数）//struct __main_block_impl_0 *__csel 指向block变量的指针static void __main_block_func_0(struct __main_block_impl_0 *__cself) {        printf("Block\n");    }static struct __main_block_desc_0 {  size_t reserved;  size_t Block_size;} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0)};int main(int argc, const char * argv[]){    //声明block    //struct _main_block_impl_0 tmp = __main_block_impl_0(__main_block_func_0,&__mian_block_desc_0_DATA)    //struct _main_block_impl_0 * blk = & tmp;    void(*blk)(void) = (void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA);        //执行block    ((void (*)(__block_impl *))((__block_impl *)blk)->FuncPtr)((__block_impl *)blk);    return 0;}

结论：Block  ＝＝ oc 对象。