The CBN_ERRSPACE notification message is sent when a combo box cannot allocate enough memory to meet a specific request. The parent window of the combo box receives this notification message through a WM_COMMAND message.
wParam
Specifies the identifier of the combo box.
lParam
Specifies the handle of the combo box in the low-order word, and specifies the CBN_ERRSPACE notification message in the high-order word.