c++基本多线程故障排除

Question

每当我尝试编译这个程序时，我都会得到错误:"错误C2661: 'std::thread::thread':没有重载函数需要7个参数"。当我尝试使用

创建线程时，我得到了这个

genparts<T>

或仅

genparts.

我现在正试着让自己熟悉线程，不管它是值得的。

我知道我不应该有一个传入这么多参数的函数，最好是传入一个带有这些信息的结构体——这是我将在一切就绪后修复的问题。

template <typename T>
void genparts(unsigned int target, unsigned int &total, unsigned int low, unsigned int high, map<unsigned int, unsigned int> container, T gen){
return;}

和调用函数:

void genpart(unsigned int target, map<unsigned int, unsigned int> &container, T& gen){
unsigned int total[2];
map<unsigned int, unsigned int> results[2];
do{
    total[0]=0;
    total[1]=0;
    thread t1(genparts<T>, target, total[0], 1, target/2, results[0], gen);
    thread t2(genparts<T>, target, total[1], 1+(target/2), target, results[1], gen);
    t1.join();
    t2.join();
}while(total[0]+total[1] != target);
}

我非常感谢你的帮助!谢谢!

Answer 1

很多细节都错了…比如你传递的参数的数量(容器去了哪里?)，你一直在复制映射。但最重要的是，需要通过引用传递给线程函数的参数需要包装在std::ref中。综上所述，这是一个"可行"的版本:

#include <map>
#include <thread>
template <typename T>
void genparts(unsigned int target, unsigned int &total,
              unsigned int low, unsigned int high,
              std::map<unsigned int, unsigned int>& container, T& gen)
{ /* ... */   }
template <typename T>
void genpart(unsigned int target,
             std::map<unsigned int, unsigned int> &container, T& gen)
{
  unsigned int total[2];
  std::map<unsigned int, unsigned int> results[2];
  do
  {
    total[0] = 0;
    total[1] = 0;
    std::thread t1(genparts<T>, target, std::ref(total[0]), 1,
                   target / 2, std::ref(container), std::ref(gen));
    std::thread t2(genparts<T>, target, std::ref(total[1]), 1 + (target / 2),
                   target, std::ref(container), std::ref(gen));
    t1.join();
    t2.join();
  } while (total[0] + total[1] != target);
}