Can I send a ctrl-C (SIGINT) to an application on

Question

I have (in the past) written cross-platform (Windows/Unix) applications which, when started from the command line, handled a user-typed Ctrl-C combination in the same way (i.e. to terminate the application cleanly).

Is it possible on Windows to send a Ctrl-C/SIGINT/equivalent to a process from another (unrelated) process to request that it terminate cleanly (giving it an opportunity to tidy up resources etc.)?

Answer 1

Based on process id, we can send the signal to process to terminate forcefully or gracefully or any other signal.

List all process :

C:\>tasklist

To kill the process:

C:\>Taskkill /IM firefox.exe /F
or
C:\>Taskkill /PID 26356 /F

Details:

http://tweaks.com/windows/39559/kill-processes-from-command-prompt/

Answer 2

It should be made crystal clear because at the moment it isn't. There is a modified and compiled version of SendSignal to send Ctrl-C (by default it only sends Ctrl+Break). Here are some binaries:

(2014-3-7) : I built both 32-bit and 64-bit version with Ctrl-C, it's called SendSignalCtrlC.exe and you can download it at: https://dl.dropboxusercontent.com/u/49065779/sendsignalctrlc/x86/SendSignalCtrlC.exe https://dl.dropboxusercontent.com/u/49065779/sendsignalctrlc/x86_64/SendSignalCtrlC.exe -- Juraj Michalak

I have also mirrored those files just in case:
32-bit version: https://www.dropbox.com/s/r96jxglhkm4sjz2/SendSignalCtrlC.exe?dl=0
64-bit version: https://www.dropbox.com/s/hhe0io7mcgcle1c/SendSignalCtrlC64.exe?dl=0

Disclaimer: I didn't build those files. No modification was made to the compiled original files. The only platform tested is the 64-bit Windows 7. It is recommended to adapt the source available at http://www.latenighthacking.com/projects/2003/sendSignal/ and compile it yourself.

Answer 3

Somehow GenerateConsoleCtrlEvent() return error if you call it for another process, but you can attach to another console application and send event to all child processes.

void SendControlC(int pid)
{
    AttachConsole(pid); // attach to process console
    SetConsoleCtrlHandler(NULL, TRUE); // disable Control+C handling for our app
    GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0); // generate Control+C event
}

Answer 4

Edit:

For a GUI App, the "normal" way to handle this in Windows development would be to send a WM_CLOSE message to the process's main window.

For a console app, you need to use SetConsoleCtrlHandler to add a CTRL_C_EVENT.

If the application doesn't honor that, you could call TerminateProcess.

Answer 5

I found all this too complicated and used SendKeys to send a CTRL-C keystroke to the command line window (i.e. cmd.exe window) as a workaround.

Answer 6

I have done some research around this topic, which turned out to be more popular than I anticipated. KindDragon's reply was one of the pivotal points.

I wrote a longer blog post on the topic and created a working demo program, which demonstrates using this type of system to close a command line application in a couple of nice fashions. That post also lists external links that I used in my research.

In short, those demo programs do the following:

• Start a program with a visible window using .Net, hide with pinvoke, run for 6 seconds, show with pinvoke, stop with .Net.
• Start a program without a window using .Net, run for 6 seconds, stop by attaching console and issuing ConsoleCtrlEvent

Edit: The amended solution from KindDragon for those who are interested in the code here and now. If you plan to start other programs after stopping the first one, you should re-enable Ctrl-C handling, otherwise the next process will inherit the parent's disabled state and will not respond to Ctrl-C.

[DllImport("kernel32.dll", SetLastError = true)]
static extern bool AttachConsole(uint dwProcessId);

[DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)]
static extern bool FreeConsole();

[DllImport("kernel32.dll")]
static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add);

// Enumerated type for the control messages sent to the handler routine
enum CtrlTypes : uint
{
  CTRL_C_EVENT = 0,
  CTRL_BREAK_EVENT,
  CTRL_CLOSE_EVENT,
  CTRL_LOGOFF_EVENT = 5,
  CTRL_SHUTDOWN_EVENT
}

[DllImport("kernel32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GenerateConsoleCtrlEvent(CtrlTypes dwCtrlEvent, uint dwProcessGroupId);

public void StopProgram(Process proc)
{
  //This does not require the console window to be visible.
  if (AttachConsole((uint)proc.Id))
  {
    // Disable Ctrl-C handling for our program
    SetConsoleCtrlHandler(null, true); 
    GenerateConsoleCtrlEvent(CtrlTypes.CTRL_C_EVENT, 0);

    // Must wait here. If we don't and re-enable Ctrl-C
    // handling below too fast, we might terminate ourselves.
    proc.WaitForExit(2000);

    FreeConsole();

    //Re-enable Ctrl-C handling or any subsequently started
    //programs will inherit the disabled state.
    SetConsoleCtrlHandler(null, false); 
  }
}

Also, plan for a contingency solution if AttachConsole() or the sent signal should fail, for instance sleeping then this:

if (!proc.HasExited)
{
  try
  {
    proc.Kill();
  }
  catch (InvalidOperationException e){}
}