How can I check the other app has been closed?

In VB, I use shell command to run some app. If it's closed by user, how can VB know?

Code:

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Private Declare Function OpenProcess Lib "Kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function GetExitCodeProcess Lib "Kernel32" (ByVal hProcess As Long, lpExitCode As Long) As Long
Private Declare Sub Sleep Lib "Kernel32" (ByVal dwMilliseconds As Long)
Const STILL_ACTIVE = &H103
Const PROCESS_QUERY_INFORMATION = &H400

'JobtoDo - Program to run


Sub Shell32Bit(ByVal JobToDo As String)

        Dim hProcess As Long
        Dim RetVal As Long
        'The next line launches JobToDo as icon,

        'captures process ID
        hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, False, Shell(JobToDo, 1))

        Do

            'Get the status of the process
            GetExitCodeProcess hProcess, RetVal

            'Sleep command recommended as well as DoEvents
            DoEvents: Sleep 100

        'Loop while the process is active
        Loop While RetVal = STILL_ACTIVE
        Msgbox "App has been unloaded!"
End Sub

Usage:

Private Sub Command1_Click()
Call Shell32Bit("C:\App\App.exe")
End Sub

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