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

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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);

delegate bool ConsoleCtrlDelegate(CtrlTypes CtrlType);

// 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);

    //Moved this command up on suggestion from Timothy Jannace (see comments below)
    FreeConsole();
                
    // Must wait here. If we don't and re-enable Ctrl-C
    // handling below too fast, we might terminate ourselves.
    proc.WaitForExit(2000);
                
    //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){}
}

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