"安全地"终止在按键上运行的C++程序？

Question

我正在尝试编写一个继续运行的模拟,直到我按下某个键(如'q'表示退出).然后在我按下之后,我希望程序完成写入当前正在写入的数据,关闭文件,然后优雅地退出(而不是按ctrl + c强制程序停止).有没有办法在C++上做到这一点？

谢谢

Answer 1

让用户按CTRL- C,但安装信号处理程序来处理它.例如,在信号处理程序中,设置全局布尔变量user_wants_to_quit.然后你的sim循环看起来像:

while ( work_to_be_done && !user_wants_to_quit) {
 …
}
// Loop exited, clean up my data

一个完整的POSIX程序(对不起,如果你希望使用Microsoft Windows),包括设置和恢复SIGINT(CTRL- C)处理程序:

#include <iostream>
#include <signal.h>

namespace {
  sig_atomic_t user_wants_to_quit = 0;

  void signal_handler(int) {
    user_wants_to_quit = 1;
  }
}

int main () {

  // Install signal handler
  struct sigaction act;
  struct sigaction oldact;
  act.sa_handler = signal_handler;
  sigemptyset(&act.sa_mask);
  act.sa_flags = 0;
  sigaction(SIGINT, &act, &oldact);


  // Run the sim loop
  int sim_loop_counter = 3;
  while( (sim_loop_counter--) && !user_wants_to_quit) {
    std::cout << "Running sim step " << sim_loop_counter << std::endl;

    // Sim logic goes here. I'll substitute a sleep() for the actual
    // sim logic
    sleep(1);

    std::cout << "Step #" << sim_loop_counter << " is now complete." << std::endl;
  }

  // Restore old signal handler [optional]
  sigaction(SIGINT, &oldact, 0);

  if( user_wants_to_quit ) {
    std::cout << "SIM aborted\n"; 
  } else {
    std::cout << "SIM complete\n";
  }

}