This message is used to find the length (in bytes) of the text associated with a window. The length does not include the null-terminating character. For edit controls and combo-box edit controls, the text is the content of the control. For lixt boxes, the text is the currently selected item. For button controls, the text is the button name. For other windows, the text is the window caption.
| Parameter | Description |
| wParam | Is not used. | |
| lParam | Is not used. |
The return value is the length of the given text.