The previous entry in the list of handles, relative to a given handle.
Data type: HANDLE
Access: Read-only
Applies to: Asynchronous request object handle, BROWSE widget, BUTTON widget, COMBO-BOX widget, CONTROL-FRAME widget, DIALOG-BOX widget, EDITOR widget, FIELD-GROUP widget, FILL-IN widget, FRAME widget, IMAGE widget, LITERAL widget, MENU-ITEM widget, Procedure object handle, RADIO-SET widget, RECTANGLE widget, SELECTION-LIST widget, Server object handle, SLIDER widget, Socket object handle, Server socket object handle, SUB-MENU widget, TEXT widget, TOGGLE-BOX widget, WINDOW widget
The following table summarizes the value of PREV-SIBLING for each relevant handle type.
| Handle type | Value of PREV-SIBLING |
|---|---|
| Asynchronous Request | The handle of the previous asynchronous request submitted for execution on the AppServer or Web Server that is running the specified request. |
| Procedure | The handle of the previous persistent procedure in the current ABL session. If the current procedure is a proxy for a persistent procedure running on an AppServer or for a Web service, specifies the previous procedure object bound to the same server handle. |
| Server | The previous server handle created in the current ABL session (independent of subtype). |
| Socket and Server-socket | The previous socket handle in the chain of socket handles for the current ABL session. Returns the Unknown value (?) for the first handle in the chain. |
| Widget | The handle of the previous widget in the widget
list. Note: A widget must first be realized before
it can become part of the list. A hidden widget cannot become part of
the list since it is not realized. A widget that is already part of
the list can be hidden and it remains part of the list.
|
If the given handle is the first handle in the list, PREV-SIBLING assumes the value of an invalid handle. To check the validity of a handle, use the VALID-HANDLE function.