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Getting the main window of a thread (VC++)

I've launched a process using CreateProcess (so I have the associated PROCESS_INFORMATION and STARTUPINFO stuff).  How do I get the process's main window?

thanks  
0
SeanPS
Asked:
SeanPS
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1 Solution
 
alexoCommented:
There is no one API to do it (because a process might not have a main window or have more than one).

Instead, you need to enumerate the top level windows using EnumWindows() and check which one corresponds with you process by comparing its GetWindowThreadProcessId() with your process ID.
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alexoCommented:
A minor correction.  GetWindowThreadProcessId() returns the thread ID and sets the second argument to the process ID.  The PROCESS_INFORMATION structure will contain both.

Something like (modulo bugs and missing parts):

    HWND global_hwnd = NULL;

    int WINAPI WinMain(...)
    {
        PROCESS_INFORMATION pi;
        CreateProcess(..., &pi);
        WaitForInputIdle(pi.hProcess, INFINITE);
        EnumWindows(EnumWindowsProc, (LPARAM)pi.dwProcessId);

        if (global_hwnd != NULL)
        {
            // Do whatever...
        }

        // ...
    }

    BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
    {
        DWORD pid;
        GetWindowThreadProcessId(hwnd, &pid);
        if (pid == (DWORD)lParam)
        {
            global_hwnd = hwnd; // Found the window
            return FALSE;
        }
        else return TRUE;
    }

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SeanPSAuthor Commented:
Adjusted points to 100
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alexoCommented:
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SeanPSAuthor Commented:
based on your original ideas, it seems that EnumThreadWindows() is a slightly better alternative.  i was hoping that i could easily create a CWinThread object from the stuff i have, but that doesn't seem to be the case.

thanks for your help
sean
0
 
alexoCommented:
>> it seems that EnumThreadWindows() is a slightly better alternative.
It is, provided that only one thread in the process is creating windows.

>> i was hoping that i could easily create a CWinThread object from the stuff i have
Check the MFC sources.  You'll see that CWinThread is a complicated beast.
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