Extracting LUWIDs

Both LUWIDs for a particular TP can be determined by issuing the GET_TP_PROPERTIES verb. The GET_TP_PROPERTIES verb returns the TP's unprotected LUWID in the luw_id field.

If the TP needs to access the protected LUWID, it must combine the opext member of the VCB with the value AP_EXTD_VCB using OR before issuing the verb. The protected LUWID will then be returned in the prot_luw_id field. If the opext field does not contain the AP_EXTD_VCB bit, the verb control block is presumed to end immediately before the prot_luw_id field.

The LUWID for a particular conversation can be determined by issuing a GET_ATTRIBUTES or MC_GET_ATTRIBUTES verb on the conversation. These verbs are modified as follows:

• A new field, luw_id, is added in which the LUWID is returned. The LUWID returned is the protected one if the conversation was allocated with synclevel field of the ALLOCATE or MC_ALLOCATE verb set to Sync Point (AP_SYNCPT); otherwise it is the unprotected one.
• Since the luw_id field cannot be incorporated within the existing verb control blocks, the TP must use a larger VCB structure. To indicate that the VCB is longer than usual, the opext field of the VCB must be combined with the value AP_EXTD_VCB using OR before calling APPC.
• The sync_level field of the GET_ATTRIBUTES or MC_GET_ATTRIBUTES verb can take an additional value, AP_SYNCPT, when the conversation was allocated with the synclevel field of the ALLOCATE or MC_ALLOCATE verb of Sync Point (AP_SYNCPT).