MSMQMessage.Class (Windows Embedded CE 6.0)

1/6/2010

This property provides the message type set by Message Queuing. A message can be a normal Message Queuing message, a positive or negative (arrival and read) acknowledgment message, or a report message.

Syntax

HRESULT get_Class( 
  long* plClass 
);

Parameters

• plClass
  Message type set by Message Queuing.

Message Queuing sets the Class property to one of the following values:

Normal messages (all messages created by your application):

• MQMSG_CLASS_NORMAL
  A normal Message Queuing message.

Positive acknowledgment messages (generated by MSMQ):

• MQMSG_CLASS_ACK_REACH_QUEUE
  The original message reached its destination queue.

• MQMSG_CLASS_ACK_RECEIVE
  The original message was retrieved by the receiving application.

Negative arrival acknowledgment messages (generated by MSMQ):

• MQMSG_CLASS_NACK_ACCESS_DENIED
  The sending application does not have access rights to the destination queue.

• MQMSG_CLASS_NACK_BAD_DST_Q
  The destination queue is not available to the sending application.

• MQMSG_CLASS_NACK_BAD_ENCRYPTION
  The destination queue manager could not decrypt a private (encrypted) message (see MSMQMessage.PrivLevel).

• MQMSG_CLASS_NACK_BAD_SIGNATURE
  Message Queuing could not authenticate the original message. The original message's digital signature is not valid.

• MQMSG_CLASS_NACK_COULD_NOT_ENCRYPT
  The source queue manager could not encrypt a private message (see MSMQMessage.PrivLevel).

• MQMSG_CLASS_NACK_HOP_COUNT_EXCEEDED
  The original message's hop count is exceeded.

• MQMSG_CLASS_NACK_Q_EXCEED_QUOTA
  The original message's destination queue is full.

• MQMSG_CLASS_NACK_REACH_QUEUE_TIMEOUT
  Either the time-to-reach-queue or time-to-be-received timer expired before the original message reached the destination queue.

  For transactional messages, this is an in-doubt negative acknowledgment. For example, the local queue manager sets this class when the message timer expires, even though a positive confirmation might be in route from the remote queue manager.

• MQMSG_CLASS_NACK_PURGED
  The message was purged before reaching the destination queue.

• MQMSG_CLASS_NACK_NOT_TRANSACTIONAL_Q
  A transactional message was sent to a nontransactional queue.

• MQMSG_CLASS_NACK_NOT_TRANSACTIONAL_MSG
  A non-transactional message was sent to a transactional queue.

• MQMSG_CLASS_NACK_UNSUPPORTED_CRYPTO_PROVIDER
  The target queue manager does not have the enhanced (128-bit) cryptographic provider installed.

Negative read acknowledgment messages (generated by MSMQ):

• MQMSG_CLASS_NACK_Q_DELETED
  The queue was deleted before the message could be read from the queue.

• MQMSG_CLASS_NACK_Q_PURGED
  The queue was purged and the message no longer exists.

• MQMSG_CLASS_NACK_RECEIVE_TIMEOUT
  The original message was not removed from the queue before its time-to-be-received timer expired.

  For transactional messages, this means that the remote queue manager has indicated that the message was not retrieved. This is the only negative acknowledgment that can be trusted to indicate the message was not retrieved.

• MQMSG_CLASS_NACK_RECEIVE_TIMEOUT_AT_SENDER
  For transactional messages only. The local queue manager has indicated that the original message was not removed from the queue before its time-to-be-received timer expired.

  This class is an in-doubt negative acknowledgment. For example, the local queue manager sets this class when the time-to-be-received timer expires, even though a positive confirmation may be in route from the remote queue manager.

Report messages (generated by MSMQ):

• MQMSG_CLASS_REPORT
  Sent each time the message enters or leaves a Message Queuing server.

Return Value

The following table describes the common return values.

Remarks

Acknowledgment messages are generated by Message Queuing when the sending application requests them. Message Queuing returns the appropriate acknowledgment message to the administration queue specified by the sending application.

Transactional messages can have two in-doubt negative acknowledgments:

• MQMSG_CLASS_NACK_REACH_QUEUE_TIMEOUT
• MQMSG_CLASS_NACK_RECEIVE_TIMEOUT_AT_SENDER

These two classes are considered in doubt because they can be set by the local queue manager even though a confirmation notification may be in route from the remote queue manager.

The only trusted negative acknowledgment is MQMSG_CLASS_NACK_RECEIVE_TIMEOUT, because this class is set by the remote queue manager.

Report messages are generated by Message Queuing when a report queue is defined at the source queue manager.

When reading messages in an administration queue or dead-letter queue, retrieve Class to find out why the message was sent to the queue.

You can also retrieve the class of a message when using Message Queuing function calls.

Equivalent Function Property

When using function calls, the class of the message can be set and retrieved using the PROPID_M_CLASS message property.

Requirements

See Also

Reference

MSMQMessage
MSMQMessage.PrivLevel
PROPID_M_CLASS