MDUID (12-byte character string)

User identifier.

This is part of the identity context of the message. For more information about message context, see Overview; also see the WebSphere MQ Application Programming Guide.

MDUID specifies the user identifier of the application that originated the message. The queue manager treats this information as character data, but does not define the format of it.

After a message has been received, MDUID can be used in the ODAU field of the OBJDSC parameter of a subsequent MQOPEN or MQPUT1 call, so that the authorization check is performed for the MDUID user instead of the application performing the open.

When the queue manager generates this information for an MQPUT or MQPUT1 call, the queue manager uses a user identifier determined from the environment.

When the user identifier is determined from the environment:

• On z/OS, the queue manager uses:

  • For batch, the user identifier from the JES JOB card or started task

  • For TSO, the log on user identifier

  • For CICS, the user identifier associated with the task

  • For IMS, the user identifier depends on the type of application:

    • For:

      • Nonmessage BMP regions

      • Nonmessage IFP regions

      • Message BMP and message IFP regions that have not issued a successful GU call

      the queue manager uses the user identifier from the region JES JOB card or the TSO user identifier. If these are blank or null, it uses the name of the program specification block (PSB).

    • For:

      • Message BMP and message IFP regions that have issued a successful GU call

      • MPP regions

      the queue manager uses one of:

      • The signed-on user identifier associated with the message

      • The logical terminal (LTERM) name

      • The user identifier from the region JES JOB card

      • The TSO user identifier

      • The PSB name

• On OS/2, the queue manager uses the string "os2".

• On i5/OS, the queue manager uses the name of the user profile associated with the application job.

• On Compaq NonStop Kernel, the queue manager uses the MQSeries principal that is defined for the Tandem user identifier in the MQSeries principal database.

• On HP OpenVMS and UNIX systems, the queue manager uses:

  • The application's logon name

  • The effective user identifier of the process if no logon is available

  • The user identifier associated with the transaction, if the application is a CICS transaction

• On VSE/ESA, this is a reserved field.

• On Windows, the queue manager uses the first 12 characters of the logged-on user name.

For the MQPUT and MQPUT1 calls, this is an input/output field if PMSETI or PMSETA is specified in the PMO parameter. Any information following a null character within the field is discarded. The null character and any following characters are converted to blanks by the queue manager. If PMSETI or PMSETA is not specified, this field is ignored on input and is an output-only field.

After the successful completion of an MQPUT or MQPUT1 call, this field contains the MDUID that was transmitted with the message. If the message has no context, the field is entirely blank.

This is an output field for the MQGET call. The length of this field is given by LNUID. The initial value of this field is 12 blank characters.