如何在特定时间后从“std::cin”读取超时

我写了一个小程序，

int main(int argc, char *argv[])
{
    int n;
    std::cout << "Before reading from cin" << std::endl;

    // Below reading from cin should be executed within stipulated time
    bool b=std::cin >> n;
    if (b)
          std::cout << "input is integer for n and it's correct" << std::endl;
    else
          std::cout << "Either n is not integer or no input for n" << std::endl;
    return 0;
 }

读自std::cin正在阻塞，因此程序会等待，直到有外部中断（也如信号）向程序或用户提供一些输入。

我该如何发表声明std::cin >> n等待一段时间（也许使用sleep()系统调用）用于用户输入？ 如果用户未提供输入，并且在规定时间（假设 10 秒）完成后，程序应恢复执行下一条指令（即if (b==1)声明开始）。

这对我有用（请注意，这在 Windows 下不起作用）：

#include <iostream>
#include <sys/select.h>

using namespace std;

int main(int argc, char *argv[])
{
    int n;
    cout<<"Before performing cin operation"<<endl;

    //Below cin operation should be executed within stipulated period of time
    fd_set readSet;
    FD_ZERO(&readSet);
    FD_SET(STDIN_FILENO, &readSet);
    struct timeval tv = {10, 0};  // 10 seconds, 0 microseconds;
    if (select(STDIN_FILENO+1, &readSet, NULL, NULL, &tv) < 0) perror("select");

    bool b = (FD_ISSET(STDIN_FILENO, &readSet)) ? (cin>>n) : false;

    if(b==1)
          cout<<"input is integer for n and it's correct"<<endl;
    else
          cout<<"Either n is not integer or no input for n"<<endl;

    return 0;
}