System.Diagnostics.Process.UpdateHasExited C# (CSharp) Method

        private void UpdateHasExited()
        {
            SafeProcessHandle handle = null;
            try
            {
                handle = GetProcessHandle(Interop.Advapi32.ProcessOptions.PROCESS_QUERY_LIMITED_INFORMATION | Interop.Advapi32.ProcessOptions.SYNCHRONIZE, false);
                if (handle.IsInvalid)
                {
                    _exited = true;
                }
                else
                {
                    int localExitCode;

                    // Although this is the wrong way to check whether the process has exited,
                    // it was historically the way we checked for it, and a lot of code then took a dependency on
                    // the fact that this would always be set before the pipes were closed, so they would read
                    // the exit code out after calling ReadToEnd() or standard output or standard error. In order
                    // to allow 259 to function as a valid exit code and to break as few people as possible that
                    // took the ReadToEnd dependency, we check for an exit code before doing the more correct
                    // check to see if we have been signaled.
                    if (Interop.Kernel32.GetExitCodeProcess(handle, out localExitCode) && localExitCode != Interop.Kernel32.HandleOptions.STILL_ACTIVE)
                    {
                        _exitCode = localExitCode;
                        _exited = true;
                    }
                    else
                    {
                        // The best check for exit is that the kernel process object handle is invalid, 
                        // or that it is valid and signaled.  Checking if the exit code != STILL_ACTIVE 
                        // does not guarantee the process is closed,
                        // since some process could return an actual STILL_ACTIVE exit code (259).
                        if (!_signaled) // if we just came from WaitForExit, don't repeat
                        {
                            using (var wh = new ProcessWaitHandle(handle))
                            {
                                _signaled = wh.WaitOne(0);
                            }
                        }
                        if (_signaled)
                        {
                            if (!Interop.Kernel32.GetExitCodeProcess(handle, out localExitCode))
                                throw new Win32Exception();

                            _exitCode = localExitCode;
                            _exited = true;
                        }
                    }
                }
            }
            finally
            {
                ReleaseProcessHandle(handle);
            }
        }