TRANSFER Programming Manual

External Object UOWs
TRANSFER Services
40970 Tandem Computers Incorporated 5–9
The TRANSFER delivery system handles attachments as follows:
Always transports primary attachments to destination nodes when the items to
which they are attached are transported.
Never transports alternate attachments to other nodes.
Views primary and alternate attachments as two separate lists; in each of these
lists, the attachments are ordered by relative position.
If the TRANSFER delivery system cannot deliver an item to another node either
because it is running a version of the TRANSFER delivery system prior to B40 (and
thus does not support external objects) or because the EXTERNAL-OBJECTS capability
is disabled on that node, the TRANSFER delivery system sends a TAREQ event
package to the originator for every recipient on that node, as discussed later in this
section. (To determine the software version code and the external objects capability
setting, an application uses the GET-CONFIG-NAME UOW, referencing the NODE-
VERSION and the EXTOBJS-ENABLED entities in the configuration directory,
respectively.)
External Object UOWs TRANSFER applications can access and use external objects through various UOWs.
An application can:
Attach an external object to an item or primary external object (ATTACH-EXTOBJ
UOW)
Retrieve the names and object IDs of objects attached to an item or to a primary
external object (GET-EXTOBJ UOW)
Detach an external object from an item or primary external object (DETACH-
EXTOBJ UOW)
Retrieve item data that includes the data records of an external object that is a
GUARDIAN 90 operating system file of type EDIT or TTEXT (GET-ITEM-REC-B40
UOW)
Selectively copy the primary or alternate attachments of an item (COPY-ITEM-B40
UOW)
Determine if the external objects capability is enabled for a local or remote node
(GET-CONFIG-NAME UOW, referencing the EXTOBJS-ENABLED entity in the
configuration directory for the node)
Enable or disable the external objects capability (SET-SYSTEM-PARAM UOW, for
system administrators only)
You can use external object IDs in place of item IDs in these UOWs unless the UOW
expects only an item ID. You can use item handles to refer to external objects in the
same way that you use them to refer to items.
If the external objects capability is disabled, the ATTACH-EXTOBJ and
DETACH-EXTOBJ UOWs return an error. The GET-EXTOBJ UOW, however,
functions because it is informational only and does not alter any current attachments.