C++ 函数在网络编程中如何处理超时和异常？

#include <chrono>

using namespace std::chrono_literals;

std::chrono::seconds timeout = 10s; // 设置 10 秒的超时

#include <sys/select.h>

int main() {
  // 设置文件描述符集合
  fd_set fds;
  FD_ZERO(&fds);
  FD_SET(socket_fd, &fds);

  // 设置超时
  struct timeval timeout;
  timeout.tv_sec = 10;
  timeout.tv_usec = 0;

  // 等待可读性或超时
  int result = select(socket_fd + 1, &fds, NULL, NULL, &timeout);

  if (result == 0) {
    // 超时
    std::cout << "Operation timed out." << std::endl;
  } else if (result > 0) {
    // 文件描述符可读
    // ...
  } else {
    // 错误
    std::cout << "An error occurred." << std::endl;
  }

  return 0;
}

#include <stdexcept>

try {
  // ...
} catch (const std::exception& e) {
  // 异常处理
  std::cout << "An exception occurred: " << e.what() << std::endl;
}

#include <iostream>

using namespace std;

int main() {
  try {
    // 建立网络连接
    // ...
  } catch (const std::runtime_error& e) {
    // 连接失败
    cout << "Connection failed: " << e.what() << endl;
  }

  return 0;
}