Start a process and obtain its main window handle

The following two functions can be used to start a process and obtain the main window handle.

Bool callback cdsupdate: enumdsumwindowsproc (hwnd, lparam)

{

DWORD dwid;

Enumparam * Pep = (enumparam *) lparam;

Getwindowthreadprocessid (hwnd, & dwid );

If (dwid = pep-> m_dwprocessid)

{

Pep-> m_hmainwnd = hwnd;

Return false;

}

Return true;

}

Hwnd cdsupdate: rundsum (cstring sdsumfile)

{

Enumparam EP;

Startupinfo Si;

Process_information PI;

Cstring sfolder;

Zeromemory (& Si, sizeof (startupinfo ));

Si. cb = sizeof (startupinfo );

Si. wshowwindow = sw_show;

Zeromemory (& Pi, sizeof (process_information ));

Updatelog (: Message, l "(rundsum): Start dsum .");

If (! CreateProcess (null, (lptstr) (lpctstr) sdsumfile, null, null, false, 0, null, sdsumfile. left (sdsumfile. reversefind ('//'), & Si, & PI ))

{

Updatelog (: error, l "(rundsum): Start dsum fail (% d).", getlasterror ());

Return NULL;

}

// Close process and thread handles.

Closehandle (PI. hprocess );

Closehandle (PI. hthread );

 

Ep. m_dwprocessid = pi. dwprocessid;

Ep. m_hmainwnd = NULL;

For (INT I = 0; I <50; I ++) // retry about 10 s.

{

Sleep (200 );

Enumwindows (enumdsumwindowsproc, (lparam) & EP );

If (Ep. m_hmainwnd)

Break;

}

If (! Ep. m_hmainwnd)

{

Updatelog (: error, l "(rundsum): couldn't find the hwnd of dsum .");

Return NULL;

}

Return ep. m_hmainwnd;

}