VB6 - How to wait for process to finish

Posted on 2004-05-01
Last Modified: 2010-07-16
Hi All,

I need to write a customizable installation program which has this process sequence:

- Install MS Access runtimes (\Access\setup.exe)
- Install our program (\Ours\setup.exe)
- Install MSDE 2000 (\MSDE\setup.exe)

This is the function I use to run those setup.exe
    cb As Long
    lpReserved As String
    lpDesktop As String
    lpTitle As String
    dwX As Long
    dwY As Long
    dwXSize As Long
    dwYSize As Long
    dwXCountChars As Long
    dwYCountChars As Long
    dwFillAttribute As Long
    dwFlags As Long
    wShowWindow As Integer
    cbReserved2 As Integer
    lpReserved2 As Long
    hStdInput As Long
    hStdOutput As Long
    hStdError As Long
End Type

    hProcess As Long
    hThread As Long
    dwProcessId As Long
    dwThreadID As Long
End Type

Private Declare Function WaitForSingleObject Lib "Kernel32" (ByVal _
         hHandle As Long, ByVal dwMilliseconds As Long) As Long

Private Declare Function CreateProcessA Lib "Kernel32" (ByVal _
         lpApplicationName As Long, ByVal lpCommandLine As String, ByVal _
         lpProcessAttributes As Long, ByVal lpThreadAttributes As Long, _
         ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, _
         ByVal lpEnvironment As Long, ByVal lpCurrentDirectory As Long, _
         lpStartupInfo As STARTUPINFO, lpProcessInformation As _

Private Declare Function CloseHandle Lib "Kernel32" (ByVal _
         hObject As Long) As Long

Private Const INFINITE = -1&

Public Function ExecCmd(commandline, Optional nothing1 As Variant)
    'nothing1 is included to be compatible with shell(command, windowstyle)
    Dim Start As STARTUPINFO
    Dim ReturnValue As Integer
    cmdline$ = commandline
    ' Initialize the STARTUPINFO structure:
    Start.cb = Len(Start)

    ' Start the shelled application:
    ReturnValue = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _
        NORMAL_PRIORITY_CLASS, 0&, 0&, Start, proc)

    ' Wait for the shelled application to finish:
        ReturnValue = WaitForSingleObject(proc.hProcess, 0)
    Loop Until ReturnValue <> 258

    ReturnValue = CloseHandle(proc.hProcess)
    ExecCmd = ReturnValue
End Function
The thing is no matter I wait for single object to excute. It still does not stop. All 3 setup program just trying to run all together. Can ne1 help? Do you have any better solution for this problem?
Question by:NguyenHuy
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Expert Comment

ID: 10968696;EN-US;96844

That might help. It shows you how to wait for a process started with Shell() to finish before continuing with your own app. So if you changed your code to run with shell, then it should work. Or you may be able to adapt it if you don't want to change the way you start your programs.

LVL 19

Expert Comment

ID: 10968763
Try this tiny little piece of software called iexpress. Click start > run > and type iexpress. It is one of the hidden candies in win2K & XP. What it does, it packes files into on exe selfextract file. So, you can tell iexpress to run installation one before the main installation, and installation three after the main installation. Check it. It might help.

LVL 28

Expert Comment

ID: 10968916
Or try this shellwait function:

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

Private Function ShellWait(PathName, Optional WindowStyle As VbAppWinStyle = vbNormalFocus) As Double
Dim hProcess As Long, RetVal As Long
    hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, False, Shell(PathName, WindowStyle))
        GetExitCodeProcess hProcess, RetVal
        DoEvents: Sleep 100
    Loop While RetVal = STILL_ACTIVE
End Function

Private Sub Command1_Click()
ShellWait "\Access\setup.exe", vbNormalFocus
ShellWait "\Ours\setup.exe", vbNormalFocus
ShellWait "\MSDE\setup.exe", vbNormalFocus
End Sub
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Author Comment

ID: 10969760
Thank you guys. I will try every method tomorrow when get back to work. Will reply shortly
LVL 48

Expert Comment

ID: 10970572
        ReturnValue = WaitForSingleObject(proc.hProcess, 0)
Loop Until ReturnValue <> 258

I think you need

Loop While ReturnValue <> 258

Except of this, it's better to replace second parameter of WaitForSingleObject with non-null value, like:
    ReturnValue = WaitForSingleObject(proc.hProcess, 100)

This gives more time to another process.
LVL 48

Expert Comment

ID: 10970576
Oops, sorry. Ignore my post (at least, it's first part).
LVL 48

Expert Comment

ID: 10970580
I think your code is OK, but there are some processes which launch another process and exit immidiately. Program that tries to wait for such process continues - this happens, for example, when we run by such way Windows Explorer. Try this code with simple process like Notepad to see whether problem is in your code or in process itself.
LVL 26

Expert Comment

ID: 10972558

Dim wshShell
Set wshShell = CreateObject("WScript.Shell")
wshShell.Run "c:\notepad.exe", 1, true
Set wshShell = Nothing

Author Comment

ID: 10985721
Today finally I got my time to test your solution
The Baker, thanks for your suggestion. I have visited that page before posting question here. The solution works somewhere else but not for me
Shauli, thanks for the tiny little gem. I did not know that XP has a self extractor program. Unfortunately that not what Im looking for.
Vin, thanks your code does not work for me. I cant explain why but I got the same result as my code.
Alex, I think you are correct. However when I try paquet builder 2.8 shareware version, it does the job nicely. So it means that there must be a way to work around this problem. I can afford to pay $30 for paquet builder, but having total control of the setup program in my hands is better anywayz.
Please let me know if you know anything good. Im willing to try anything possible

Accepted Solution

modulo earned 0 total points
ID: 11468903
PAQed, with points refunded (500)

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