请教,关于 C++中 char 二进制数据释放的问题 - V2EX
V2EX = way to explore
V2EX 是一个关于分享和探索的地方
Sign Up Now
For Existing Member  Sign In
Symbo1ic
V2EX    C++

请教,关于 C++中 char 二进制数据释放的问题

  •  
  •   Symbo1ic May 23, 2023 2180 views
    This topic created in 1070 days ago, the information mentioned may be changed or developed.

    今天做项目的时候遇到了这样一个需求:需要读取一个二进制到指定的数据结构中,并释放二进制数据。 这个二进制数据大小是确定的,为 1024B 。现在我遇到两个问题:一是无论怎么释放这个 char*都会遇到 exception 。我尝试过使用 unique_ptr 进行包装,也尝试过直接使用 delete[] ptr 但都不好使。想问各位大神这种情况应该怎么释放数据? 二是在 main 中的 memcpy 之后,任何 cout 内容都会转移到 badbit 状态,这个我没有查到相关的资料,请问这是什么情况? 代码附上:

    int main() { file_system::Block block; file_system::IndexData index_data; std::unique_ptr<char> data(index_data.GetBlock()); //GetBlock 返回一个 char* memcpy(block.data, data.get(), sizeof(char) * block_size); //data.release(); file_system::IndexData index_data2(&block); for (auto &i: index_data2.index_vector) { std::cout << i.name; } } char *GetBlock() { char *data = new char[block_size]; //block_size 为常数 1024 char *dataptr = data; //max_index_size 为常数 for (int i = 0; i < max_index_size; ++i) { //复制数据 memcpy(dataptr + sizeof(Index) * i, index_vector[i].name, sizeof(char) * name_size); memcpy(dataptr + sizeof(Index) * i + sizeof(char) * name_size, &index_vector[i].handle, sizeof(short)); } memcpy(dataptr + sizeof(char) * block_size - sizeof(short), &next_index_block_handle, sizeof(short)); return data; } 
    5 replies    2023-05-23 20:34:03 +08:00
    ripperdev
        1
    ripperdev  
       May 23, 2023
    unique_ptr 的 release 函数并不会释放内存,只是释放所有权并返回裸指针。具体的 exception 是什么呢?贴出来看看
    Symbo1ic
        2
    Symbo1ic  
    OP
       May 23, 2023
    @ripperdev
    debug 时会停在 memory 的 3129 行,提示:Exception: Exception 0x80000003 encountered at address 0x7ffe8212f3d2
    memory 部分如下所示
    ```
    void operator()(_Ty* _Ptr) const noexcept /* strengthened */ { // delete a pointer
    static_assert(0 < sizeof(_Ty), "can't delete an incomplete type");
    delete _Ptr;
    }
    ```
    myh0000
        3
    myh0000  
       May 23, 2023
    release 同楼上
    有可能是 memcpy 越界了,自己观察下 dataptr
    Symbo1ic
        4
    Symbo1ic  
    OP
       May 23, 2023
    @myh0000 感谢大佬指点!最后还是 memcpy 越界了。之前在定义常数的时候定义值为正常的两倍,因此出了越界问题
    myh0000
        5
    myh0000  
       May 23, 2023
    嘿嘿
    About     Help     Advertise     Blog     API     FAQ     Solana     3081 Online   Highest 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 202ms UTC 14:48 PVG 22:48 LAX 07:48 JFK 10:48
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86