Waiting for a reply

Use the MQGET call to retrieve a reply from your request message. One request message can produce several reply messages. For details, see Interpreting the replies.

We can specify a time interval that an MQGET call waits for a reply message to be generated. If you do not get a reply, use the checklist beginning in topic If you do not receive a reply.

To use the MQGET call:

1. Set these parameters:

   Hconn

   The connection handle returned by the MQCONN or MQCONNX call.

   Hobj

   The object handle returned by the MQOPEN call for the reply-to queue.

   Buffer

   The name of the area to receive the reply.

   BufferLength

   The length of the buffer to receive the reply. This must be a minimum of 80 bytes.

2. To ensure that you only get the responses from the command that you issued, specify the appropriate MsgId and CorrelId fields. These depend on the report options, MQMD_REPORT, you specified in the MQPUT call:

   MQRO_NONE

   Binary zero, '00...00' (24 nulls).

   MQRO_NEW_MSG_ID

   Binary zero, '00...00' (24 nulls).

   This is the default if none of these options has been specified.

   MQRO_PASS_MSG_ID

   The MsgId from the MQPUT.

   MQRO_NONE

   The MsgId from the MQPUT call.

   MQRO_COPY_MSG_ID_TO_CORREL_ID

   The MsgId from the MQPUT call.

   This is the default if none of these options has been specified.

   MQRO_PASS_CORREL_ID

   The CorrelId from the MQPUT call.

   For more details on report options, see the WebSphere MQ Application Programming Reference manual.

3. Set the following GetMsgOpts fields:

   Options

   MQGMO_WAIT

   If you are not using the same code page as the queue manager, set MQGMO_CONVERT, and set CodedCharSetId as appropriate in the MQMD.

   WaitInterval

   For replies from the local queue manager, try 5 seconds. Coded in milliseconds, this becomes 5 000. For replies from a remote queue manager, and channel control and status commands, try 30 seconds. Coded in milliseconds, this becomes 30 000.

 

Discarded messages

If the command server finds that a request message is not valid, it discards this message and writes the message CSQN205I to the named reply-to queue. If there is no reply-to queue, the CSQN205I message is put onto the dead-letter queue. The return code in this message shows why the original request message was not valid:

00D5020F	It is not of type MQMT_REQUEST.
00D50210	It has zero length.
00D50212	It is longer than 32 762 bytes.
00D50211	It contains all blanks.
00D5483E	It needed converting, but Format was not MQFMT_STRING.
Other	See the WebSphere MQ for z/OS Messages and Codes manual.