CWnd::ShowWindow
Visual Studio 2010
Sets the visibility state of the window.
BOOL ShowWindow( int nCmdShow );
ShowWindow must be called only once per application for the main window with CWinApp::m_nCmdShow. Subsequent calls to ShowWindow must use one of the values listed above instead of the one specified by CWinApp::m_nCmdShow.
See the example for CWnd::CalcWindowRect.