c++ - 将多个参数从另一个类传递给线程函数

Question

假设我有一个类:

class This
{ 
    void that(int a, int b);
};

在我的主函数中，我需要在一个线程中启动“that”，并向它传递 2 个参数。 这是我的:

void main()
{
   This t;
   t.that(1,2);  //works unthreaded.

   std::thread test(t.that(1,2)); // Does not compile. 'evaluates to a function taking 0 arguments'

   std::thread test2(&This::that, std::ref(t), 1, 2); //runs, but crashes with a Debug error.
}

我搜索过，但只找到了如何将参数传递给线程，以及如何在线程中运行另一个类的函数，但不是两者!

正确的做法是什么？

Answer 1

为了在另一个线程中运行This，您要么必须制作一个拷贝，要么确保它在另一个线程运行时仍然有效。尝试其中之一:

引用

This t;

std::thread test([&]() {
    t.that(1,2); // this is the t from the calling function
});

// this is important as t will be destroyed soon
test.join();

复制

This t;

std::thread test([=]() {
    t.that(1,2); // t is a copy of the calling function's t
});

// still important, but does not have to be in this function any more
test.join();

动态分配

auto t = std::make_shared<This>();

std::thread(test[=]() {
    t->that(1,2); // t is shared with the calling function
});

// You still have to join eventually, but does not have to be in this function
test.join();