The TBN_GETBUTTONINFO message retrieves toolbar customization information and notifies the toolbar’s parent window of any changes being made to the toolbar. This is sent in the form of a WM_NOTIFY message.
TBN_GETBUTTONINFO ptbn = (TBNOTIFY FAR *) lParam;
The pszText member specifies the address of the current button text, and cchText specifies its length in characters. The application should fill the structure with information about the button.
Returns TRUE if button information was copied to the specified structure or FALSE otherwise.
The toolbar control allocates a buffer, and the receiver (parent window) must copy the text into that buffer. The cchText member contains the length of the buffer allocated by the toolbar when TBN_GETBUTTONINFO is sent to the parent window.