LUWID Specified by SET_TP_PROPERTIES Verb May Be Overwritten (314807)

SYMPTOMS

An Advanced Program-to-Program Communications (APPC) application that uses the SET_TP_PROPERTIES verb to specify a logical unit-of-work identifier (LUWID) may have its LUWID overwritten by an LUWID that is generated by the SNA Server service (Snaservr.exe) on a subsequent ALLOCATE exchange.

CAUSE

The APPC library (Wappc32.dll) does not correctly save LUWID values that are specifically set by a SET_TP_PROPERTIES verb. Therefore, the APPC library allows the LUWID to be overwritten by an LUWID that is generated by the SNA Server service.

STATUS

SNA Server 4.0:

Microsoft has confirmed that this is a problem in Microsoft SNA Server versions 4.0, 4.0 Service Pack (SP) 1, 4.0 SP2, 4.0 SP3, 4.0 SP4. Host Integration Server 2000:

Microsoft has confirmed that this is a problem in Microsoft Host Integration Server 2000.

MORE INFORMATION

An APPC application that uses the Sync Point feature can use the SET_TP_PROPERTIES verb to set its LUWIDs. To do this, the SET_TP_PROPERTIES verb specifies an existing value or asks the SNA Server service to generate a new one. An LUWID that is set by a SET_TP_PROPERTIES verb should not be overwritten for the duration of the APPC transaction unless another SET_TP_PROPERTIES verb is issued with a new LUWID value. An APPC transaction begins with a TP_STARTED verb and ends with a TP_ENDED verb. The transaction may include multiple ALLOCATE exchanges.

See the APPC Programmer's Guide in the SNA Server or Host Integration Server 2000 Software Development Kit (SDK) for more details on the SET_TP_PROPERTIES verb.

For additional information on how the SNA Server service generates LUWIDs, click the article number below to view the article in the Microsoft Knowledge Base:

175375 New Format for Logical Unit of Work Identifier