int GetWindowText( LPSTR lpString, int nMaxCount ) const;
lpString
Points to the buffer that is to receive the copied string of the Window's title.
nMaxCount
Specifies the maximum number of characters to be copied to the buffer. If the string is longer than the number of characters specified in nMaxCount, it is truncated.
Copies CWnd's caption title (if it has one) into the buffer pointed to by lpString. If the CWnd object is a control, the GetWindowText member function copies the text within the control instead of copying the caption.
Specifies the length of the copied string. It is 0 if CWnd has no caption or if the caption is empty.
CWnd::SetWindowText, CWnd::GetWindowText, WM_GETTEXT