小编Mat*_*son的帖子

在C++11其中std::atomic_flag，对于线程循环很有用：

static std::atomic_flag s_done(ATOMIC_FLAG_INIT);

void ThreadMain() {
    while (s_done.test_and_set()) {  // returns current value of s_done and sets to true
        // do some stuff in a thread
    }
}

// Later:
  s_done.clear();  // Sets s_done to false so the thread loop will drop out

该ATOMIC_FLAG_INIT组的标志false，这意味着该线程永远不会在循环。一个（不好的）解决方案可能是这样做的：

void ThreadMain() {
    // Sets the flag to true but erases a possible false
    // which is bad as we may get into a deadlock
    s_done.test_and_set();
    while …

分配给的内存是多少char *ptr:

#include <iostream>
using namespace std;
class A
{ 
  private:
  int count;
  char *ptr;                                 
  public :
  void print()
  {    
  cout << "Addr " << &ptr << endl;     
  cout << "Addr " << *ptr << endl;     
  }       

};

int main()
{
 A obj;
 obj.print();
 A *obj1 = new A(obj); 
 obj1->print();
 cin.get();             
 return 0;   
}

我正在使用编译器提供的复制构造函数.我有兴趣了解我将分配多少内存*ptr.

我是Maven的新手.

如何创建maven-archetype-nar-exec项目类型？

如果我跑,mvn -archetype=generate我没有选择的选项maven-archetype-nar-exec？

我是否必须将某些内容下载到Maven存储库中？

我正在使用 Maven 3.0.3

为什么不在此代码中调用析构函数:

#include <iostream>
#include <thread>
#include <memory>

class base {
    public:
        base() {
            std::cout << "base()" << std::endl;
        }
        virtual ~base() {
            std::cout << "~base()" << std::endl;
        }
        base(const base&) = delete;
        base(base&&) = delete;
        base& operator=(const base&) = delete;
        base& operator=(base&&) = delete;
};

class derived final : public base {
    public:
        derived() {
            std::cout << "derived()" << std::endl;
        }
        virtual ~derived() {
            std::cout << "~derived()" << std::endl;
        }
};


void foo() {
    static thread_local std::unique_ptr<base> ptr; …