Terminating a thread

[Nucleus]

I have used the messagebox api function to create an async message box. Now I want to terminate the thread containing the messagebox without terminating my applicaiton as well.

I can get the handle of the thread using GetWindowThreadProcessId().

Now to try to terminate the thread. I presume I need to use OpenThread API, before using TerminateThread. Problem is, I can't find a VB declare statement for this API.

Here is the link to the MSDN function definition:
http://msdn.microsoft.com/library/de...thred_8xb8.asp

Any help with a translation would be appreciated

Here is what I am trying to do:

Option Explicit
Private Declare Function MessageBoxEx Lib "user32" Alias "MessageBoxExA" (ByVal hwnd As Long, ByVal lpText As String, ByVal lpCaption As String, ByVal uType As Long, ByVal wLanguageId As Long) As Long
 
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hwnd As Long, lpdwProcessId As Long) As Long
Private Declare Function TerminateThread Lib "kernel32" (ByVal hThread As Long, ByVal dwExitCode As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function GetExitCodeThread Lib "kernel32" (ByVal hThread As Long, lpExitCode As Long) As Long
Private Declare Sub ExitThread Lib "kernel32" (ByVal dwExitCode As Long)
 
 
Private Sub Command1_Click()
'display asynch message box
    MessageBoxEx 0&, "Pulchritude" & vbNewLine & "Ansync Messagebox", "Discombobulated", 0&, 0
End Sub
 
 
Private Sub Command2_Click()
'attempt to close asynch message box
Dim hwnd                As Long
Dim Pid                 As Long
Dim TID                 As Long
Dim lpExitCode          As Long
Dim hThread             As Long
 
hwnd = FindWindow("#32770", "Discombobulated")
 
If hwnd Then
    
    TID = GetWindowThreadProcessId(hwnd, Pid)
    Call GetExitCodeThread(TID, lpExitCode)
    'fine to here but now what? 
 
End If
End Sub

[Nucleus]

Here is my attempt:

Private Declare Function OpenThread Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwThreadId As Long) As Long

However I get an error "no insertion point OpenThread in Kernel32"?

Also I can't find out the values for the constants but I assume if I pass 1, I get complete access to the thread.

[CornedBee]

Platform SDK Release: August 2001

Maybe this is WinXP only?

[Nucleus]

Whah

Damn it, and I really need to be able to terminate an existing thread.

[CornedBee]

You could write the handle of the thread to a secret file and later load it, so you can call TerminateThread directly on the handle. BTW, ExitThread and TerminateThread are bad functions because they imediatly kill the thread without giving it a chance to clean up resources they used. If there is any other way (like setting a global variable), you should use it.
Or maybe finding the window of the messagebox and calling EndDialog on it. Or a WM_COMMAND message with the ID IDOK. There are many ways, most of them better than calling TerminateThread.

[Nucleus]

EndDialog is the business. Does it clean up system resources?

[CornedBee]

I'm not sure. Also, I just found this in MSDN:

An application calls EndDialog from within the dialog box procedure; the function must not be used for any other purpose.

So I'm not sure if it's ok to call this function. I think
SendMessage(hDlg, WM_COMMAND, MAKELONG(IDOK, BN_CLICKED), GetDlgItem(hDlg, IDOK));
is still the cleanest solution. But I don't know how to emulate or access MAKELONG in VB. It basically combines two 16-bit values (integers in VB) to one 32-bit (long in VB).
Here is the C definition of MAKELONG, maybe you know how to convert it:

#define MAKELONG(a, b)      ((LONG)(((WORD)(a)) | ((DWORD)((WORD)(b))) << 16))

long is 32 bit, word is 16 bit and dword is 32 bit.

[Nucleus]

Ok thanks.