Question

我知道这个问题是重复的，但是我找不到其他对我的案例有帮助的问题的答案。我应该提一下，我对C ++还是很陌生，可能犯了许多与线程模块无关的错误。我的目标是使lamda表达式在线程中不断运行，此lambda函数将在每次按下空格键时向值添加一个。然后程序检查该值以查看它是否大于10，如果大于10，则程序退出。问题是每次我尝试构建它时（使用Visual Studio Community 2019），都会出现以下错误：

'std::invoke': no matching overloaded function found

Failed to specialize function template 'unknown-type std::invoke(_Callable &&,_Types &&...) noexcept(<expr>)'

这是我的代码：

#include <thread>
#include <iostream>
#include <Windows.h>

using std::thread;
using std::cout;
using std::endl;

int main()
{
    //Value modified by the lambda expression, when it becomes greater than 10,
    //the program will wait for the thread to finish and then exit.
    int number = 0;

    //Value to be checked by the lambda expression everytime the loop repeats,
    //if it is false, the loop will break.
    bool programRunning = true;

    //Lambda expression to update number on screen when spacebar is pressed.
    auto update = [](bool& isRunning, int& number) {
        while (isRunning)
        {
            //If space is pressed
            if (GetAsyncKeyState(VK_SPACE) != 0)
            {
                //Add one to the number, this is what the program checks to see if it should exit.
                number++;
                system("cls");
            }
            cout << "The current number is " << number << endl;
            Sleep(500);
        }
    };

    //Creating thread from lambda function and passing references of programRunning and number.
    thread Updater(update, &programRunning, &number);

    //Checks if the number modified by the lambda expression is greater than 10,
    //if so, the program waits for the thread to finish and then exits.
    while (true)
    {
        if (number > 10)
        {
            programRunning = false;
            Updater.join();
            exit(0);
        }
        else
        {
            Sleep(500);
        }
    }
}

'std :: invoke'：在C ++中使用线程时，没有匹配的重载函数

0 个答案: