This message could be used to return text that represents the current position of the slider arm or to query the text for use in ownerdraw mode.

By specifying 0 as the value of the usBufLen parameter and then looking at the value returned in the sTextLen parameter, an application can determine the size of the buffer to allocate for copying the text. An application can then allocate a buffer of this size, adding one byte for the null termination character, and then specify this buffer and size on the query call.