C++ 中文周刊第66期

从reddit/hackernews/lobsters/meetingcpp摘抄一些c++动态

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20220610更新。本期内容少的可怜

资讯

标准委员会动态/ide/编译器信息放在这里

博览网之前的送书活动又开始了，需要付个邮费

扫码就行了

文章

C++协程在阿里的推广和大规模应用

阿里居然有c++编译器团队

源码阅读 gflags，发现设计缺陷

值得一看

Data structure size and cache-line accesses

测了一组不同大小的结构体用的数据

Assessing a read-after free for security implications: The string comparison

std::string GetThemeName();

void Vulnerable()
{
    auto theme = GetThemeName().c_str();
    if (strcmp(theme, "Light") == 0) {
        SetLightTheme();
    } else if (strcmp(theme, "Dark") == 0) {
        SetDarkTheme();
    } else {
        SetDefaultTheme();
    }
}

这种异常泄漏有被攻击的可能性

https://www.sandordargo.com/blog/2022/06/08/smart-pointers-and-deleters

Unique ptr的指定delete是模版参数的一部分，没有type erease，不同类型deleter就不能赋值了

template <typename T>
struct FakeDeleter {
  void operator()(T *ptr){
    std::cout << "FakeDeleter doesn't delete\n";
  } 
};

template <typename T>
struct LoggingDeleter {
    void operator()(T *ptr){
    std::cout << "LoggingDeleter is at work\n";
    delete ptr;
  } 
};
std::unique_ptr<int, FakeDeleter<int>> upFD (new int(42), FakeDeleter<int>());
std::unique_ptr<int, FakeDeleter<int>> upFD2 (new int(51), FakeDeleter<int>());
std::unique_ptr<int, LoggingDeleter<int>> upLD (new int(42), LoggingDeleter<int>());
upFD = std::move(upFD2); // OK
upFD = std::move(upLD); // NOT OK, fails to compile!
std::shared_ptr<int> spFD (new int(51), FakeDeleter<int>());
std::shared_ptr<int> spFD2 (new int(51), FakeDeleter<int>());
std::shared_ptr<int> spLD (new int(51), LoggingDeleter<int>());
spFD = spFD2;
spFD = spLD;