process - Stuck on GenerateConsoleCtrlEvent in C# with console apps

Question

I'm having the hardest time trying to get this to work, hoping one of you has done this before.

I have a C# console app that is running a child process which inherits its console. I want a ctrl-c caught by the outer app to be passed along to the inner app so that it can have a chance to shut down nicely.

I have some very simple code. I start a Process, then poll it with WaitForExit(10). I also have a CancelKeyPress handler registered, which sets a bool to true when it fires. The polling loop also checks this, and when it's true, it calls GenerateConsoleCtrlEvent() (which I have mapped through pinvoke).

I've tried a lot of combinations of params to GenerateConsoleCtrlEvent(). 0 or 1 for the first param, and either 0 or the child process's ID for the second param. Nothing seems to work. Sometimes I get a false back and Marshal.GetLastWin32Error() returns 0, and sometimes I get true back. But none cause the child app to receive a ctrl-c.

To be absolutely sure, I wrote a test C# app to be the child app which prints out what's going on with it and verified that manually typing ctrl-c when it runs does properly cause it to quit.

I've been banging my head against this for a couple hours. Can anyone give me some pointers on where to go with this?

Answer 1

Not so sure this is a good approach. This only works if the child process is created with the CREATE_NEW_PROCESS_GROUP flag for CreateProcess(). The System.Diagnostics.Process class however does not support this.

Consider using the return value from the Main() method. There is already a unique value defined in the Windows SDK for Ctrl+C aborts, STATUS_CONTROL_C_EXIT or 0xC000013A. The parent process can get that return code from the Process.ExitCode property.