Check if a Shell Process Ends
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wailing_.. #1 / 3
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 Check if a Shell Process Ends
Hi Everybody, Badly need help on this: My VB app needs to install 3 softwares one after another. These 3 softwares are installation packages packaged using InstallShield. My SHELL for the 3 softwares works in a similar fashion like this: strProg = "d:\gricdial.exe" If Dir(strProg) <> "" Then Screen.MousePointer = vbHourglass Shell strProg, vbNormalFocus ExecCmd (strProg) Screen.MousePointer = vbDefault Else MsgBox "Cannot execute installation program for Global Roaming", vbExclamation End If To ensure that the first software completes installation before installing the next, I used the source code provided by VB (see attached file) : 96.htm (without the Sub Form_Click()) The problem was: Once InstallShield for the first app starts, it hangs my VB app. I have to end task my VB app before the installation software can continue.
Thanks, Candice
[
96.htm 12K ]
HOWTO: 32-Bit App Can Determine When a Shelled Process Ends
The information in this article applies to:
- Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0
- Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0
SUMMARY
Executing the Shell() function in a Visual Basic for Windows program starts
another executable program asynchronously and returns control to the Visual
Basic application. This shelled program continues to run independently of your
application until the user closes it.
However, if your Visual Basic application needs to wait for the shelled process
to terminate, you could use the Windows API to poll the status of the
application, but this is not a very efficient technique. The example in this
article demonstrates a better way.
A 16-bit application would use a completely different technique to accomplish the
same effect. For additional information on the 16-bit process, please refer the
following Knowledge Base article:
Q96844 : HOWTO: Determine When a Shelled Process Has Terminated
MORE INFORMATION
The Win32 API has integrated functionality that enables an application to wait
until a shelled process has completed. To use these functions, you need a handle
to the shelled process. The easiest way to achieve this is to use the
CreateProcess() API function to launch your shelled program rather than Visual
Basic[ASCII 146]s Shell() function.
Creating the Shelled Process
In a 32-bit application, you need to create an addressable process. To do this,
use the CreateProcess() function to start your shelled application. The
CreateProcess() function gives your program the process handle of the shelled
process via one of its passed parameters.
Waiting for the Shelled Process to Terminate
Having used CreateProcess() to get a process handle, pass that handle to the
WaitForSingleObject() function. This causes your Visual Basic application to
suspend execution until the shelled process terminates.
Getting the Exit Code from the Shelled Application
It was common for a DOS application to return an exit code indicating the status
of the completed application. While Windows provides other ways to convey the
same information, some applications only provide exit codes. Passing the process
handle to the GetExitCodeProcess() API allows you to retrieve this information.
Below are the steps necessary to build a Visual Basic for Windows program that
uses the CreateProcess() function to execute the Windows Notepad (NOTEPAD.EXE)
application. This code demonstrates how to use the Windows API CreateProcess()
and WaitForSingleObject() functions to wait until a shelled process terminates
before resuming execution. It also uses the GetExitCodeProcess() function to
retrieve the exit code of the shelled process, if any.
The syntax of the CreateProcess() function is extremely complicated, so in the
example code, it is encapsulated into a function called ExecCmd(). ExecCmd()
takes one parameter, the command line of the application to execute.
Step-by-Step Example
1. Start a new project in Visual Basic. Form1 is created by default.
2. Add the following code to the General Declarations section of Form1:
Private Type STARTUPINFO
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
Private Type PROCESS_INFORMATION
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 _
PROCESS_INFORMATION) As Long
Private Declare Function CloseHandle Lib "kernel32" _
(ByVal hObject As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32" _
(ByVal hProcess As Long, lpExitCode As Long) As Long
Private Const NORMAL_PRIORITY_CLASS = &H20&
Private Const INFINITE = -1&
Public Function ExecCmd(cmdline$)
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO
' Initialize the STARTUPINFO structure:
start.cb = Len(start)
' Start the shelled application:
ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _
NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)
' Wait for the shelled application to finish:
ret& = WaitForSingleObject(proc.hProcess, INFINITE)
Call GetExitCodeProcess(proc.hProcess, ret&)
Call CloseHandle(proc.hProcess)
ExecCmd = ret&
End Function
Sub Form_Click()
Dim retval As Long
retval = ExecCmd("notepad.exe")
MsgBox "Process Finished, Exit Code " & retval
End Sub
3. Press the F5 key to run the application.
4. Using the mouse, click the Form1 window. At this point the NotePad
application is started.
5. Terminate NotePad. A MsgBox will appear indicating termination of the NotePad
application and an exit code of 0. To test this sample with an application
that returns an exit code, implement Knowledge Base article Q178357 and
change the parameter passed to ExecCmd to "project1.exe." NOTE: The MsgBox
statement following the ExecCmd() function is not executed because the
WaitForSingleObject() function prevents it. The message box does not appear
until Notepad is closed when the user chooses Exit from Notepad's File menu
(ALT, F, X).
REFERENCES
Q178357 : HOWTO: Set an Error Level from a Visual Basic Application
Additional query words: GetModuleUsage kbVBp400 kbVBp600 kbVBp kbdsd kbDSupport
Keywords :
Version : WINDOWS:4.0,6.0
Platform : WINDOWS
Issue type : kbhowto
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Sun, 25 Nov 2001 03:00:00 GMT |
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Bj?rn Holmgre #2 / 3
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 Check if a Shell Process Ends
HOWTO: 32-Bit App Can Determine When a Shelled Process EndsHi! Normally, it's possible to use the WaitForSingleObject API to determine when a process ends. However, with Installshield, this is not possible. The reason for this is that the main InstallShield process only unpacks the installation files, then starts a second process named "_ins0432._mp" - or something like that - that runs the actual installation. The main process then exits, way before the installation is completed. What you need to do is wait for the second process to complete. To do that, you must enumerate all the processes until you find the installation program, retrieve it's handle and then wait for it to end (using WaitForSingleObject). A simple workaround is to use the FindWindow API to wait for the installation program to start and end. All you need to know then is the title of the installation program's main window. The following example will wait for a window to appear and then disappear before continuing: Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long Private Sub WaitForWindow(WindowClass As String, WindowTitle As String) Dim WindowHandle As Long While WindowHandle = 0 WindowHandle = FindWindow(ByVal WindowClass, ByVal WindowTitle) DoEvents Wend While WindowHandle <> 0 WindowHandle = FindWindow(ByVal WindowClass, ByVal WindowTitle) DoEvents Wend End Sub To use the WaitForWindow sub use the following syntax: WaitForWindow vbNullString, "Title of window" The first parameter is the name of the window class. Normally you won't need to specify this, but if you have more than one window with the same title, the class name can help you select the correct window. Of course, you will then need some sort of utility to determine the class name.
Hi Everybody, Badly need help on this: My VB app needs to install 3 softwares one after another. These 3 softwares are installation packages packaged using InstallShield. My SHELL for the 3 softwares works in a similar fashion like this: strProg = "d:\gricdial.exe" If Dir(strProg) <> "" Then Screen.MousePointer = vbHourglass Shell strProg, vbNormalFocus ExecCmd (strProg) Screen.MousePointer = vbDefault Else MsgBox "Cannot execute installation program for Global Roaming", vbExclamation End If To ensure that the first software completes installation before installing the next, I used the source code provided by VB (see attached file) : 96.htm (without the Sub Form_Click()) The problem was: Once InstallShield for the first app starts, it hangs my VB app. I have to end task my VB app before the installation software can continue.
Thanks, Candice ------------------------------------------------------------------------------ HOWTO: 32-Bit App Can Determine When a Shelled Process Ends The information in this article applies to: a.. Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0 b.. Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0 SUMMARY Executing the Shell() function in a Visual Basic for Windows program starts another executable program asynchronously and returns control to the Visual Basic application. This shelled program continues to run independently of your application until the user closes it. However, if your Visual Basic application needs to wait for the shelled process to terminate, you could use the Windows API to poll the status of the application, but this is not a very efficient technique. The example in this article demonstrates a better way. A 16-bit application would use a completely different technique to accomplish the same effect. For additional information on the 16-bit process, please refer the following Knowledge Base article: Q96844 : HOWTO: Determine When a Shelled Process Has Terminated MORE INFORMATION The Win32 API has integrated functionality that enables an application to wait until a shelled process has completed. To use these functions, you need a handle to the shelled process. The easiest way to achieve this is to use the CreateProcess() API function to launch your shelled program rather than Visual Basic[ASCII 146]s Shell() function. Creating the Shelled Process In a 32-bit application, you need to create an addressable process. To do this, use the CreateProcess() function to start your shelled application. The CreateProcess() function gives your program the process handle of the shelled process via one of its passed parameters. Waiting for the Shelled Process to Terminate Having used CreateProcess() to get a process handle, pass that handle to the WaitForSingleObject() function. This causes your Visual Basic application to suspend execution until the shelled process terminates. Getting the Exit Code from the Shelled Application It was common for a DOS application to return an exit code indicating the status of the completed application. While Windows provides other ways to convey the same information, some applications only provide exit codes. Passing the process handle to the GetExitCodeProcess() API allows you to retrieve this information. Below are the steps necessary to build a Visual Basic for Windows program that uses the CreateProcess() function to execute the Windows Notepad (NOTEPAD.EXE) application. This code demonstrates how to use the Windows API CreateProcess() and WaitForSingleObject() functions to wait until a shelled process terminates before resuming execution. It also uses the GetExitCodeProcess() function to retrieve the exit code of the shelled process, if any. The syntax of the CreateProcess() function is extremely complicated, so in the example code, it is encapsulated into a function called ExecCmd(). ExecCmd() takes one parameter, the command line of the application to execute. Step-by-Step Example 1. Start a new project in Visual Basic. Form1 is created by default. 2. Add the following code to the General Declarations section of Form1: Private Type STARTUPINFO 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 Private Type PROCESS_INFORMATION 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 _ PROCESS_INFORMATION) As Long Private Declare Function CloseHandle Lib "kernel32" _ (ByVal hObject As Long) As Long Private Declare Function GetExitCodeProcess Lib "kernel32" _ (ByVal hProcess As Long, lpExitCode As Long) As Long Private Const NORMAL_PRIORITY_CLASS = &H20& Private Const INFINITE = -1& Public Function ExecCmd(cmdline$) Dim proc As PROCESS_INFORMATION Dim start As STARTUPINFO ' Initialize the STARTUPINFO structure: start.cb = Len(start) ' Start the shelled application: ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _ NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc) ' Wait for the shelled application to finish: ret& = WaitForSingleObject(proc.hProcess, INFINITE) Call GetExitCodeProcess(proc.hProcess, ret&) Call CloseHandle(proc.hProcess) ExecCmd = ret& End Function Sub Form_Click() Dim retval As Long retval = ExecCmd("notepad.exe") MsgBox "Process Finished, Exit Code " & retval End Sub 3. Press the F5 key to run the application. 4. Using the mouse, click the Form1 window. At this point the NotePad application is started. 5. Terminate NotePad. A MsgBox will appear indicating termination of the NotePad application and an exit code of 0. To test this sample with an application that returns an exit code, implement Knowledge Base article Q178357 and change the parameter passed to ExecCmd to "project1.exe." NOTE: The MsgBox statement following the ExecCmd() function is not executed because the WaitForSingleObject() function prevents it. The message box does not appear until Notepad is closed when the user chooses Exit from Notepad's File menu
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Sun, 25 Nov 2001 03:00:00 GMT |
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Paul Mathe #3 / 3
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 Check if a Shell Process Ends
HOWTO: 32-Bit App Can Determine When a Shelled Process EndsYou're supposed to be able to use the AppActivate function for that purpose. Otherwise, you may want to use a .BAT file to launch one after the other. Dim MyAppID Dim strProg as String strProg = "d:\gricdial.exe" If Dir(strProg) <> "" Then Screen.MousePointer = vbHourglass MyAppID = Shell (strProg, vbNormalFocus) AppActivate MyAppID ExecCmd (strProg) Screen.MousePointer = vbDefault Else MsgBox "Cannot execute installation program for Global Roaming", vbExclamation) End If -- Paul Mather University of Cincinnati
Hi Everybody, Badly need help on this: My VB app needs to install 3 softwares one after another. These 3 softwares are installation packages packaged using InstallShield. My SHELL for the 3 softwares works in a similar fashion like this: strProg = "d:\gricdial.exe" If Dir(strProg) <> "" Then Screen.MousePointer = vbHourglass Shell strProg, vbNormalFocus ExecCmd (strProg) Screen.MousePointer = vbDefault Else MsgBox "Cannot execute installation program for Global Roaming", vbExclamation End If To ensure that the first software completes installation before installing the next, I used the source code provided by VB (see attached file) : 96.htm (without the Sub Form_Click()) The problem was: Once InstallShield for the first app starts, it hangs my VB app. I have to end task my VB app before the installation software can continue.
Thanks, Candice ------------------------------------------------------------------------------ HOWTO: 32-Bit App Can Determine When a Shelled Process Ends The information in this article applies to: a.. Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0 b.. Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0 SUMMARY Executing the Shell() function in a Visual Basic for Windows program starts another executable program asynchronously and returns control to the Visual Basic application. This shelled program continues to run independently of your application until the user closes it. However, if your Visual Basic application needs to wait for the shelled process to terminate, you could use the Windows API to poll the status of the application, but this is not a very efficient technique. The example in this article demonstrates a better way. A 16-bit application would use a completely different technique to accomplish the same effect. For additional information on the 16-bit process, please refer the following Knowledge Base article: Q96844 : HOWTO: Determine When a Shelled Process Has Terminated MORE INFORMATION The Win32 API has integrated functionality that enables an application to wait until a shelled process has completed. To use these functions, you need a handle to the shelled process. The easiest way to achieve this is to use the CreateProcess() API function to launch your shelled program rather than Visual Basic[ASCII 146]s Shell() function. Creating the Shelled Process In a 32-bit application, you need to create an addressable process. To do this, use the CreateProcess() function to start your shelled application. The CreateProcess() function gives your program the process handle of the shelled process via one of its passed parameters. Waiting for the Shelled Process to Terminate Having used CreateProcess() to get a process handle, pass that handle to the WaitForSingleObject() function. This causes your Visual Basic application to suspend execution until the shelled process terminates. Getting the Exit Code from the Shelled Application It was common for a DOS application to return an exit code indicating the status of the completed application. While Windows provides other ways to convey the same information, some applications only provide exit codes. Passing the process handle to the GetExitCodeProcess() API allows you to retrieve this information. Below are the steps necessary to build a Visual Basic for Windows program that uses the CreateProcess() function to execute the Windows Notepad (NOTEPAD.EXE) application. This code demonstrates how to use the Windows API CreateProcess() and WaitForSingleObject() functions to wait until a shelled process terminates before resuming execution. It also uses the GetExitCodeProcess() function to retrieve the exit code of the shelled process, if any. The syntax of the CreateProcess() function is extremely complicated, so in the example code, it is encapsulated into a function called ExecCmd(). ExecCmd() takes one parameter, the command line of the application to execute. Step-by-Step Example 1. Start a new project in Visual Basic. Form1 is created by default. 2. Add the following code to the General Declarations section of Form1: Private Type STARTUPINFO 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 Private Type PROCESS_INFORMATION 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 _ PROCESS_INFORMATION) As Long Private Declare Function CloseHandle Lib "kernel32" _ (ByVal hObject As Long) As Long Private Declare Function GetExitCodeProcess Lib "kernel32" _ (ByVal hProcess As Long, lpExitCode As Long) As Long Private Const NORMAL_PRIORITY_CLASS = &H20& Private Const INFINITE = -1& Public Function ExecCmd(cmdline$) Dim proc As PROCESS_INFORMATION Dim start As STARTUPINFO ' Initialize the STARTUPINFO structure: start.cb = Len(start) ' Start the shelled application: ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _ NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc) ' Wait for the shelled application to finish: ret& = WaitForSingleObject(proc.hProcess, INFINITE) Call GetExitCodeProcess(proc.hProcess, ret&) Call CloseHandle(proc.hProcess) ExecCmd = ret& End Function Sub Form_Click() Dim retval As Long retval = ExecCmd("notepad.exe") MsgBox "Process Finished, Exit Code " & retval End Sub 3. Press the F5 key to run the application. 4. Using the mouse, click the Form1 window. At this point the NotePad application is started. 5. Terminate NotePad. A MsgBox will appear indicating termination of the NotePad application and an exit code of 0. To test this sample with an application that returns an exit code, implement Knowledge Base article Q178357 and change the parameter passed to ExecCmd to "project1.exe." NOTE: The MsgBox statement following the ExecCmd() function is not executed because the WaitForSingleObject() function prevents it. The message box does not appear until Notepad is closed when the user chooses Exit from Notepad's File menu (ALT, F, X). REFERENCES Q178357 : HOWTO: Set an Error Level from a Visual Basic Application Additional query words: GetModuleUsage kbVBp400 kbVBp600 kbVBp kbdsd kbDSupport Keywords : Version : WINDOWS:4.0,6.0 Platform : WINDOWS Issue type : kbhowto Last Reviewed: May 7, 1999 ? 1999 Microsoft Corporation. All rights reserved. Terms of Use. Article ID: Q129796 Last Reviewed: May 7, 1999 Provided by Support Online from Microsoft Product Support Services. ------------------------------------------------------------------ Did the information in this article help answer your question? Yes No Did not apply Please provide additional comments about this information. If you require a response or technical support, please click Contact Us. (255 character max)
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Fri, 30 Nov 2001 03:00:00 GMT |
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