Use of the message descriptor

The PCF command type is obtained from the system item with selector MQIASY_TYPE. When you create your data bag, the initial value of this item is set depending on the type of bag you create:

Table 16. PCF command type
Type of bag Initial value of MQIASY_TYPE item
MQCBO_ADMIN_BAG MQCFT_COMMAND
MQCBO_COMMAND_BAG MQCFT_COMMAND
MQCBO_* MQCFT_USER

When the MQAI generates a message descriptor, the values used in the Format and MsgType parameters depend on the value of the system item with selector MQIASY_TYPE as shown in Table 16.

Table 17. Format and MsgType parameters of the MQMD
PCF command type Format MsgType
MQCFT_COMMAND MQFMT_ADMIN MQMT_REQUEST
MQCFT_REPORT MQFMT_ADMIN MQMT_REPORT
MQCFT_RESPONSE MQFMT_ADMIN MQMT_REPLY
MQCFT_TRACE_ROUTE MQFMT_ADMIN MQMT_DATAGRAM
MQCFT_EVENT MQFMT_EVENT MQMT_DATAGRAM
MQCFT_* MQFMT_PCF MQMT_DATAGRAM

Table 17 shows that if you create an administration bag or a command bag, the Format of the message descriptor is MQFMT_ADMIN and the MsgType is MQMT_REQUEST. This is suitable for a PCF request message sent to the command server when a response is expected back.

Other parameters in the message descriptor take the values shown in Table 18.

Table 18. Message descriptor values
Parameter Value
StrucId MQMD_STRUC_ID
Version MQMD_VERSION_1
Report MQRO_NONE
MsgType see Table 17
Expiry 30 seconds (note 1)
Feedback MQFB_NONE
Encoding MQENC_NATIVE
CodedCharSetId depends on the bag CCSID (note 2)
Format see Table 17
Priority MQPRI_PRIORITY_AS_Q_DEF
Persistence MQPER_NOT_PERSISTENT
MsgId MQMI_NONE
CorelId MQCI_NONE
BackoutCount 0
ReplyToQ see note 3
ReplyToQMgr blank
Notes:
  1. This value can be overridden on the mqExecute call by using the OptionsBag parameter. For information about this, see mqExecute.
  2. See Data conversion.
  3. Name of the user-specified reply queue or MQAI-generated temporary dynamic queue for messages of type MQMT_REQUEST. Blank otherwise.