优雅地终止基于 Boost Asio 的 Windows 控制台应用程序

2021-12-24 00:00:00 windows-console c++ boost boost-asio taskkill

我正在开发基于 boost.asio 的 HTTP 服务器.它应该在外部停止.我们使用 asio 信号处理，它适用于 ctrl-c，但不处理 WM_CLOSE，因此没有直接的方法从外部优雅地关闭应用程序，例如通过 taskkill.强制终止进程不是一种选择.有没有已知的方法来解决这个问题?

I am working on a boost.asio based HTTP server. It is supposed to be stopped externally. We use asio signal handling, and it works well for ctrl-c, but does not handle WM_CLOSE, so there is no straightforward way to gracefully close the application externally, e.g. via taskkill. Terminating the process forcibly is not an option. Is there a known approach to this?

推荐答案

更新

只需使用您通常"使用的任何 IPC 方法

Just use any IPC method you would "normally" use

  1. 编写一个简单的过程控制实用程序，它使用例如named_condition 通知你的 asio 进程关闭.

  1. Write a simple process control utility that uses e.g. named_condition to signal your asio process to shutdown.

请注意，named_codition 有点等同于 Win32 命名事件，以防您认为对于这个固有平台特定的代码段更简单

Note that named_codition is somewhat equivalent to a Win32 Named Event in case you think that simpler for this inherently platform specific piece of code

考虑制作一个 Windows 服务 (NTService)，看起来像就像这就是你想要的

Consider making a Windows Service (NTService), as it looks like this is what you want


原答案，处理如何监听控制台关闭事件:

Original answer, dealing with how to listen for console close events:

这确实与使用 Boost Asio 无关.当然，在 POSIX 平台上，您可以使用 boost::asio::signal_set 来处理 SIG_INT 和 SIG_TERM 信号.

This is really not related to using Boost Asio. Of course, on POSIX platforms you could use boost::asio::signal_set to handle the SIG_INT and SIG_TERM signals.

但是，您使用的是 Windows，并且没有可移植的方法来检测控制台关闭事件.

However, you're on windows, and there is no portable way to detect console close event.

您应该编写一个控制台处理程序例程来检测 CTRL_CLOSE_EVENT(和 CTRL_C_EVENT，如果需要)，并使用 SetConsoleCtrlHandler 将处理程序例程添加到您的进程中.

You should write a console handler routine that detects CTRL_CLOSE_EVENT (and CTRL_C_EVENT, if desired), and use SetConsoleCtrlHandler to add the handler routine to your process.

#include <windows.h> 
#include <stdio.h> 

BOOL CtrlHandler( DWORD fdwCtrlType ) 
{ 
  switch( fdwCtrlType ) 
  { 
    // Handle the CTRL-C signal. 
    case CTRL_C_EVENT: 
      printf( "Ctrl-C event

" );
      Beep( 750, 300 ); 
      return( TRUE );

    // CTRL-CLOSE: confirm that the user wants to exit. 
    case CTRL_CLOSE_EVENT: 
      Beep( 600, 200 ); 
      printf( "Ctrl-Close event

" );
      return( TRUE ); 

    // Pass other signals to the next handler. 
    case CTRL_BREAK_EVENT: 
      Beep( 900, 200 ); 
      printf( "Ctrl-Break event

" );
      return FALSE; 

    case CTRL_LOGOFF_EVENT: 
      Beep( 1000, 200 ); 
      printf( "Ctrl-Logoff event

" );
      return FALSE; 

    case CTRL_SHUTDOWN_EVENT: 
      Beep( 750, 500 ); 
      printf( "Ctrl-Shutdown event

" );
      return FALSE; 

    default: 
      return FALSE; 
  } 
} 

int main( void ) 
{ 
  if( SetConsoleCtrlHandler( (PHANDLER_ROUTINE) CtrlHandler, TRUE ) ) 
  { 
    printf( "
The Control Handler is installed.
" ); 
    printf( "
 -- Now try pressing Ctrl+C or Ctrl+Break, or" ); 
    printf( "
    try logging off or closing the console...
" ); 
    printf( "
(...waiting in a loop for events...)

" ); 

    while( 1 ){ } 
  } 
  else 
  {
    printf( "
ERROR: Could not set control handler"); 
    return 1;
  }
return 0;
}

为了与 Boost Asio 协调，您可以让处理程序停止(全局)io_service 对象，并可能为运行操作设置一些标志.最后，您可能必须取消任何正在进行的异步操作(例如 deadline_timers).

To coordinate with Boost Asio, you could have the handler stop the (global) io_service object and perhaps set some flag for running actions. Finally, you may have to cancel any async operations in flight (e.g. deadline_timers).

一旦你这样做了，它应该很干净.

Once you did that, it should be pretty clean.

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