4 Reference

To Set Connection Properties

1. Call the MQCreateProperties function to get a handle to a newly created properties object

2. Call a function to set one of the connection properties listed in Table 4-2.

   Which function you call depends on the type of the property you want to set; for example, to set an MQString property, you call the MQSetStringProperty function; to set a MQBool property, you call the MQSetBoolProperty function; and so on. Each function that sets a property requires that you pass a key name (constant) and value; these are listed and described in Table 4-2.

3. When you have set all the properties you want to define for the connection, you can then create the connection, by calling the MQCreateConnection function.

   The runtime library sets the connection properties that specify the name and version of the Message Queue product; you can retrieve these using the MQGetMetaData function. These properties are described at the end of Table 4-2, starting with MQ_NAME_PROPERTY.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. The client runtime specifies this handle when it calls your message listener.

consumerHandle

A handle to the consumer receiving the message. The client runtime specifies this handle when it calls your message listener.

messageHandle

A handle to the incoming message. The client runtime specifies this handle when it calls your message listener.

callbackData

The void pointer that you passed to the function MQCreateAsyncMessageConsumer or the function MQCreateAsyncDurableMessageConsumer.

The body of a message listener function is written by the receiving client. Mainly, the function needs to process the incoming message by examining its header, body, and properties. The client is also responsible for freeing the message handle (either from within the handler or from outside the handler) by calling MQFreeMessage.

In addition, you should observe the following guidelines when writing the message listener function:

• If you specify MQ_CLIENT_ACKNOWLEDGE as the acknowledge mode for the session, you must explicitly call the MQAcknowledgeMessages function to acknowledge messages that you have received. For more information, see the description of the function MQAcknowledgeMessages.

• Do not try to close the session (or the connection to which it belongs) and consumer handle in the message listener.

• It is possible for a message listener to return an error; however, this is considered a client programming error. If the listener discovers that the message is badly formatted or if it cannot process it for some other reason, it should handle the problem itself by re-directing it to an application-specific bad-message destination and process it later.

  If the message listener does return an error, the client runtime will try to redeliver the message once if the session's acknowledge mode is either MQ_AUTO_ACKNOWLEDGE or MQ_DUPS_OK_ACKNOWLEDGE .

Parameters

sessionHandle

The handle to the session to which this consumer belongs. The client runtime specifies this handle when it calls your message listener.

consumerHandle

A handle to the consumer receiving the message. The client runtime specifies this handle when it calls your message listener.

messageHandle

A handle to the incoming message. The client runtime specifies this handle when it calls your message listener.

errorCode

Client runtime processing status that is passed to the before/after callback functions.

callbackData

The void pointer that is passed to the function MQCreateAsyncMessageConsumer.

Parameters

connectionHandle

The handle to the connection on which the connection exception occurred. The client runtime sets this handle when it calls the connection exception handler.

exception

An MQStatus for the connection exception that occurred. The client runtime specifies this value when it calls the exception handler.

You can pass this status result to any functions used to handle errors to get an error code or error string. For more information, see Error Handling.

callbackData

Whatever void pointer was passed as the listenerCallbackData parameter to the functionMQCreateConnection for more information.

The body of a connection exception listener function is written by the client. This function will only be called synchronously with respect to a single connection. If you install it as the connection exception listener for multiple connections, then it must be reentrant.

Do not try to close the session (or the connection to which it belongs) in the exception listener.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session for the consumer that received the specified message.

messageHandle

A handle to the message that you want to acknowledge. This handle is passed back to you when you receive the message (either by calling one of the receive functions or when a message is delivered to your message listener function.)

Whether you receive messages synchronously or asynchronously, you can call the MQAcknowledgeMessages function to acknowledge receipt of the specified message and of all messages that preceded it.

When you create a session you specify one of several acknowledge modes for that session; these are described in Table 4-3. If you specify MQ_CLIENT_ACKNOWLEDGE as the acknowledge mode for the session, you must explicitly call the MQAcknowledgeMessages function to acknowledge receipt of messages consumed in that session.

By default, the calling thread to the MQAcknowledgeMessages function will be blocked until the broker acknowledges receipt of the acknowledgment for the broker consumed. If, when you created the session's connection, you specified the property MQ_ACK_ON_ACKNOWLEDGE_PROPERTY to be MQ_FALSE, the calling thread will not wait for the broker to acknowledge the acknowledgement.

Common Errors

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection that you want to close. This handle is created and passed back to you by the function MQCreateConnection.

Closing the connection closes all sessions, producers, and consumers created from this connection. This also forces all threads associated with this connection that are blocking in the library to return.

Closing the connection does not actually release all the memory associated with the connection. After all the application threads associated with this connection (and its dependent sessions, producers, and consumers) have returned, you should call the MQFreeConnection function to release these resources. However, MQFreeConnection () does not release resources held by a message or a destination associated with this connection. You must free memory allocated for a message or a destination by explicitly calling the MQFreeMessage or the MQFreeDestination function.

Common Errors

MQ_CONCURRENT_DEADLOCK (If the function is called from an exception listener or a consumer's message listener.)

MQ_ILLEGAL_CLOSE_XA_CONNECTION (If called to claose an XA connection.)

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

consumerHandle

The handle to the consumer you want to close. This handle is created and passed back to you by one of the functions used to create consumers.

This handle is invalid after the function returns successfully.

A session's consumers are automatically closed when you close the session or connection to which they belong. To close a consumer without closing the session or connection to which it belongs, use the functionMQCloseMessageConsumer.

If the consumer you want to close is a durable consumer and you want to close this consumer permanently, you should call the function MQUnsubscribeDurableMessageConsumer after closing the consumer in order to delete any state information maintained by the broker for this consumer.

Common Errors

MQ_CONSUMER_NOT_IN_SESSION
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

producerHandle

A handle for this producer that was passed to you by the functionMQCreateMessageProducer or by the function MQCreateMessageProducerForDestination.

This handle is invalid after the function returns successfully.

Use the MQCloseMessageProducer function to close a producer without closing its associated session or connection.

Common Errors

MQ_PRODUCER_NOT_IN_SESSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session that you want to close. This handle is created and passed back to you by the MQCreateSession function.

This handle is invalid after the function returns successfully.

Closing a session closes the resources (producers and consumers) associated with that session and frees up the memory allocated for that session.

Calling this function does not release resources held by a message or a destination associated with this session. You must free memory allocated for a message or a destination by explicitly calling the MQFreeMessage or the MQFreeDestination function.

There is no need to close the producers or consumers of a closed session.

Common Errors

MQ_CONCURRENT_DEADLOCK

(If called from a consumer's message listener in the session.)

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the transacted session that you want to commit.

A transacted session supports a series of transactions. Transactions organize a session's input message stream and output message stream into a series of atomic units. A transaction's input and output units consist of those messages that have been produced and consumed within the session's current transaction. (Note that the receipt of a message cannot be part of the same transaction that produces the message.) When you call the MQCommitSession function, its atomic unit of input is acknowledged and its associated atomic unit of output is sent.

The completion of a session's current transaction automatically begins the next transaction. The result is that a transacted session always has a current transaction within which its work is done. Use the MQRollBackSession () function to roll back a transaction.

Common Errors

MQ_NOT_TRANSACTED_SESSION
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_NOT_TRANSACTED_SESSION
MQ_XA_SESSION_IN_PROGRESS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. This handle is passed back by the MQCreateSession function. For this asynchronous durable consumer, the session must have been created with the MQ_SESSION_ASYNC_RECEIVE receive mode.

destinationHandle

A handle to a topic destination on which the consumer receives messages. This handle remains valid after the call.

durableName

An MQString specifying a name for the durable subscriber. The library makes a copy of the durableName string.

messageSelector

An expression (based on SQL92 conditional syntax) that specifies the criteria upon which incoming messages should be selected for this consumer.

Specify a NULL or empty string to indicate that there is no message selector for this consumer. In this case, all messages are delivered.

The library makes a copy of the messageSelector string.

For more information about SQL, see X/Open CAE Specification Data Management: Structured Query Language (SQL), Version 2, ISBN 1-85912-151-9, March 1966.

noLocal

Specify MQ_TRUE to inhibit delivery of messages published by this consumer's own connection.

messageListener

The name of an MQMessageListenerFunc type callback function that is to be called when this consumer receives a message on the specified destination.

listenerCallbackData

A pointer to data that you want passed to your message listener function when it is called by the library.

consumerHandle

Output parameter for the handle that references the consumer for the specified destination.

In the case of an asynchronous consumer, you should not start a connection before calling the MQCreateAsyncDurableMessageConsumer function. (You should create a connection, create a session, set up your asynchronous consumer, create the consumer, and then start the connection.) Attempting to create a consumer when the connection is not stopped, will result in an MQ_CONCURRENT_ACCESS error.

The MQCreateAsyncDurableMessageConsumer function creates an asynchronous durable message consumer for the specified destination. You can define parameters to filter messages and to inhibit the delivery of messages you published to your own connection. Note that the session's receive mode (sync/async) must be appropriate for the kind of consumer you are creating (sync/async). To create a synchronous durable message consumer for a destination, call the function MQCreateDurableMessageConsumer.()

Durable consumers can only be used for topic destinations. If you are creating an asynchronous consumer for a queue destination or if you are not interested in messages that arrive to a topic while you are inactive, you might prefer to use the function MQCreateAsyncMessageConsumer.

The broker retains a record of this durable subscription and makes sure that all messages from the publishers to this topic are retained until they are either acknowledged by this durable subscriber or until they have expired. Sessions with durable subscribers must always provide the same client identifier. (See MQCreateConnection, clientID parameter.) In addition, each durable consumer must specify a durable name using the durableName parameter, which uniquely identifies (for each client identifier) the durable subscription when it is created.

A session's consumers are automatically closed when you close the session or connection to which they belong. However, messages will be routed to the durable subscriber while it is inactive and delivered when the durable consumer is recreated. To close a consumer without closing the session or connection to which it belongs, use the MQCloseMessageConsumer function. If you want to close a durable consumer permanently, you should call the MQUnsubscribeDurableMessageConsumer after closing it to delete state information maintained by the Broker on behalf of the durable consumer.

Common Errors

MQ_NOT_ASYNC_RECEIVE_MODE
MQ_INVALID_MESSAGE_SELECTOR
MQ_DESTINATION_CONSUMER_LIMIT_EXCEEDEED
MQ_TEMPORARY_DESTINATION_NOT_IN_CONNECTION
MQ_CONSUMER_NO_DURABLE_NAME
MQ_QUEUE_CONSUMER_CANNOT_BE_DURABLE
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. This handle is created and passed back to you by the MQCreateSession function. For this asynchronous consumer, the session must have been created with the MQ_SESSION_ASYNC_RECEIVE receive mode.

destinationHandle

A handle to the destination on which the consumer receives messages. This handle remains valid after the call returns.

messageSelector

An expression (based on SQL92 conditional syntax) that specifies the criteria upon which incoming messages should be selected for this consumer.

Specify a NULL or empty string to indicate that there is no message selector for this consumer. In this case, all messages will be delivered.

The library makes a copy of the messageSelector string.

For more information about SQL, see X/Open CAE Specification Data Management: Structured Query Language (SQL), Version 2, ISBN 1-85912-151-9, March 1966.

noLocal

Specify MQ_TRUE to inhibit delivery of messages published by this consumer's own connection.

The setting of this parameter applies only to topic destinations. It is ignored for queues.

messageListener

The name of an MQMessageListenerFunc type callback function that is to be called when this consumer receives a message for the specified destination.

listenerCallbackData

A pointer to data that you want passed to your message listener function when it is called by the library.

consumerHandle

Output parameter for the handle that references the consumer for the specified destination.

In the case of an asynchronous consumer, you should not start a connection before calling the MQCreateAsyncDurableMessageConsumer function. (You should create a connection, create a session, set up your asynchronous consumers, create the consumer, and then start the connection.) Attempting to create a consumer when the connection is not stopped will result in an MQ_CONCURRENT_ACCESS error.

The MQCreateAsyncMessageConsumer function creates an asynchronous message consumer for the specified destination. You can define parameters to filter messages and to inhibit the delivery of messages you published to your own connection. Note that the session's receive mode (sync/async) must be appropriate for the kind of consumer you are creating (sync/async). To create a synchronous message consumer for a destination, use the MQCreateMessageConsumer function.

If this consumer is on a topic destination, it will only receive messages produced while the consumer is active. If you are interested in receiving messages published while this consumer is not active, you should create a consumer using the MQCreateAsyncDurableMessageConsumer function instead.

A session's consumers are automatically closed when you close the session or connection to which they belong. To close a consumer without closing the session or connection to which it belongs, use the MQCloseMessageConsumer function.

Common Errors

MQ_NOT_ASYNC_RECEIVE_MODE
MQ_INVALID_MESSAGE_SELECTOR
MQ_DESTINATION_CONSUMER_LIMIT_EXCEEDEED
MQ_TEMPORARY_DESTINATION_NOT_IN_CONNECTION
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

Output parameter for the handle to the new, empty message.

After you obtain the handle to a bytes message, you can use this handle to define its content with the MQSetBytesMessageBytesMQSetBytesMessageBytes function, to set its headers with the MQSetMessageHeaders function, and to set its properties with the MQSetMessageProperties function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle that specifies the properties that determine the behavior of this connection. You must create this handle using the MQCreateProperties function before you try to create a connection. This handle will be invalid after the function returns successfully.

See Table 4-2 for information about connection properties.

username

An MQString specifying the user name to use when connecting to the broker.

The library makes a copy of the username string.

password

An MQString specifying the password to use when connecting to the broker.

The library makes a copy of the password string.

clientID

An MQString used to identify the connection. If you use the connection for a durable consumer, you must specify a non-NULL client identifier.

The library makes a copy of the clientID string.

exceptionListener

A connection-exception callback function used to notify the user that a connection exception has occurred.

listenerCallBackData

A data pointer that can be passed to the connection exceptionListener callback function whenever it is called. The user can set this pointer to any data that may be useful to pass along to the connection exception listener for this connection. Set this to NULL if you do not need to pass data back to the connection exception listener.

connectionHandle

Output parameter for the handle to the connection that is created by this function.

The MQCreateConnection function creates a connection to the broker. The behavior of the connection is specified by key values defined in the properties referenced by the propertiesHandle parameter. You must use the MQCreateProperties function to define these properties.

You cannot change the properties of a connection you have already created. If you need different connection properties, you must close and free the old connection and then create a new connection with the desired properties.

• Use the MQStartConnection function to start or restart the connection. Use the MQStopConnection function to stop a connection.

• Use the MQGetMetaData function to get information about the name of the Message Queue product and its version.

• Use the MQCloseConnection function to close a connection, and then use the MQFreeConnection function to free the memory allocated for that connection.

Common Errors

MQ_INCOMPATIBLE_LIBRARY
MQ_CONNECTION_UNSUPPORTED_TRANSPORT
MQ_COULD_NOT_CREATE_THREAD
MQ_INVALID_CLIENT_ID
MQ_CLIENT_ID_IN_USE
MQ_COULD_NOT_CONNECT_TO_BROKER
MQ_SSL_NOT_INITIALIZED

This error can be returned if MQ_CONNECTION_TYPE_PROPERTY is SSL and you have not called the MQInitializeSSL function before creating this connection.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session with which you want to associate this destination.

destinationName

An MQString specifying the logical name of this destination. The library makes a copy of the destinationName string. See discussion below.

Destination names starting with "mq" are reserved and should not be used by clients.

destinationType

An enum specifying the destination type, either MQ_QUEUE_DESTINATION or MQ_TOPIC_DESTINATION.

destinationHandle

Output parameter for the handle to the newly created destination. You can pass this handle to functions sending messages or to message producers or consumers.

The MQCreateDestination function creates a logical destination and passes a handle to it back to you. Note that the Message Queue administrator has to also create a physical destination on the broker, whose name and type is the same as the destination created here, in order for messaging to happen. For example, if you use this function to create a queue destination called myMailQDest, the administrator has to create a physical destination on the broker named myMailQDest.

If you are doing development, you can simplify this process by turning on the imq.autocreate.topic or imq.autocreate.queue properties for the broker. If you do this, the broker automatically creates a physical destination whenever a message consumer or message producer attempts to access a non-existent destination. The auto-created destination will have the same name as the logical destination name you specified using the MQCreateDestination function. By default, the broker has the properties imq.autocreate.topic and imq.autocreate.queue turned on.

Common Errors

MQ_INVALID_DESTINATION_TYPE
MQ_SESSION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. This handle is passed back to you by the MQCreateSession function. For this (synchronous) durable consumer, the session must have been created with the MQ_SESSION_SYNC_RECEIVE receive mode.

destinationHandle

A handle to a topic destination on which the consumer receives messages. This handle remains valid after the call returns.

durableName

An MQString specifying the name of the durable subscriber to the topic destination. The library makes a copy of the durableName string.

messageSelector

An expression (based on SQL92 conditional syntax) that specifies the criteria upon which incoming messages should be selected for this consumer.

Specify a NULL or empty string to indicate that there is no message selector for this consumer. In this case, the consumer receives all messages. The library makes a copy of the messageSelector string.

For more information about SQL, see X/Open CAE Specification Data Management: Structured Query Language (SQL), Version 2, ISBN 1-85912-151-9, March 1966.

noLocal

Specify MQ_TRUE to inhibit delivery of messages published by this consumer's own connection.

consumerHandle

Output parameter for the handle that references the consumer for the specified destination.

The MQCreateDurableMessageConsumer function creates a synchronous message consumer for the specified destination. A durable consumer receives all the messages published to a topic, including the ones published while the subscriber is inactive.

You can define parameters to filter messages and to inhibit the delivery of messages you published to your own connection. Note that the session's receive mode (sync/async) must be appropriate for the kind of consumer you are creating (sync/async). To create an asynchronous durable message consumer for a destination, call the function MQCreateAsyncDurableMessageConsumer.

Durable consumers are for topic destinations. If you are creating a consumer for a queue destination or if you are not interested in messages that arrive to a topic while you are inactive, you should use the function MQCreateMessageConsumer.()

The broker retains a record of this durable subscription and makes sure that all messages from the publishers to this topic are retained until they are either acknowledged by this durable subscriber or until they have expired. Sessions with durable subscribers must always provide the same client identifier (see MQCreateConnection, clientID parameter). In addition, each durable consumer must specify a durable name using the durableName parameter, which uniquely identifies (for each client identifier) the durable subscription when it is created.

A session's consumers are automatically closed when you close the session or connection to which they belong. However, messages will be routed to the durable subscriber while it is inactive and delivered when the durable consumer is recreated. To close a consumer without closing the session or connection to which it belongs, use the MQCloseMessageConsumer function. If you want to close a durable consumer permanently, you should call the MQUnsubscribeDurableMessageConsumer function after closing it to delete state information maintained by the broker on behalf of the durable consumer.

Common Errors

MQ_NOT_SYNC_RECEIVE_MODE
MQ_INVALID_MESSAGE_SELECTOR
MQ_DESTINATION_CONSUMER_LIMITE_EXCEEDEED
MQ_TEMPORARY_DESTINATION_NOT_IN_CONNECTION
MQ_CONSUMER_NO_DURABLE_NAME
MQ_QUEUE_CONSUMER_CANNOT_BE_DURABLE
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

Output parameter for the handle that references the newly created message.

Use the MQCreateMessage function to create a message that has a header and, optionally, properties, but which does not have a body. Such messages might be used by applications to signal events, which could be specified using header fields or message properties. This could improve performance because the message does not have a body and therefore there is no body to parse.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. This handle is passed back to you by the MQCreateSession function. For this (synchronous) consumer, the session must have been created with the MQ_SESSION_SYNC_RECEIVE receive mode.

destinationHandle

A handle to the destination on which the consumer receives messages. This handle remains valid after the call returns.

messageSelector

An expression (based on SQL92 conditional syntax) that specifies the criteria upon which incoming messages should be selected for this consumer. Specify a NULL or empty string to indicate that there is no message selector for this consumer and that all messages should be returned.

The library makes a copy of the messageSelector string.

For more information about SQL, see X/Open CAE Specification Data Management: Structured Query Language (SQL), Version 2, ISBN 1-85912-151-9, March 1966.

noLocal

Specify MQ_TRUE to inhibit delivery of messages published by this consumer's own connection. This applies only to topic destinations; it is ignored for queues.

consumerHandle

Output parameter for the handle that references the consumer for the specified destination.

The MQCreateMessageConsumer() function creates a synchronous message consumer for the specified destination. You can define parameters to filter messages and to inhibit the delivery of messages you published to your own connection. Note that the session's receive mode (sync/async) must be appropriate for the kind of consumer you are creating (sync/async). To create an asynchronous message consumer for a destination, use the MQCreateAsyncMessageConsumer function.

If the consumer is a topic destination, it can only receive messages that are published while it is active. To receive messages published while this consumer is not active, you should create a consumer using either the MQCreateDurableMessageConsumer function or the MQCreateAsyncDurableMessageConsumer function, depending on the receive mode you defined for the session.

A session's consumers are automatically closed when you close the session or connection to which they belong. To close a consumer without closing the session or connection to which it belongs, use the MQCloseMessageConsumer () function.

Common Errors

MQ_NOT_SYNC_RECEIVE_MODE
MQ_INVALID_MESSAGE_SELECTOR
MQ_DESTINATION_CONSUMER_LIMIT_EXCEEDEED
MQ_TEMPORARY_DESTINATION_NOT_IN_CONNECTION
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this producer should belong.

producerHandle

Output parameter for the handle that references the producer.

The MQCreateMessageProducer function creates a message producer that does not have a specified destination. In this case, you will specify the destination when sending the message itself by using either the MQSendMessageToDestination function or the MQSendMessageToDestinationExt function.

Using the MQCreateMessageProducer function is appropriate when you want to use the same producer to send messages to a variety of destinations. If, on the other hand, you want to use one producer to send many messages to the same destination, you should use the MQCreateMessageProducerForDestination function instead.

A session's producers are automatically closed when you close the session or connection to which they belong. To close a producer without closing the session or connection to which it belongs, use the MQCloseMessageProducer function.

Common Errors

MQ_SESSION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this producer belongs.

destinationHandle

A handle to the destination where you want this producer to send all messages. This handle remains valid after the call returns.

producerHandle

Output parameter for the handle that references the producer.

The MQCreateMessageProducerForDestination function creates a message producer with a specified destination. All messages sent out by this producer will go to that destination. Use the MQSendMessage function or the MQSendMessageExt function to send messages for a producer with a specified destination.

Use the MQCreateMessageProducer function when you want to use one producer to send messages to a variety of destinations.

A session's producers are automatically closed when you close the session or connection to which they belong. To close a producer without closing the session or connection to which it belongs, use the MQCloseMessageProducer () function.

Common Errors

MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

Output parameter for the handle that references the newly created properties object.

Use the MQCreateProperties function to get a properties handle. You can then use the appropriate MQSet...Property function to set the desired properties.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection to which this session belongs. This handle is passed back to you by the MQCreateConnection function. You can create multiple sessions on a single connection.

isTransacted

An MQBool specifying whether this session is transacted. Specify MQ_TRUE if the session is transacted. In this case, the acknowledgeMode parameter is ignored.

acknowledgeMode

An enumeration of the possible kinds of acknowledgement modes for the session. See Acknowledge Modes for information on these values.

After you have created a session, you can determine its acknowledgement mode by calling the MQGetAcknowledgeMode function.

receiveMode

An enumeration specifying whether this session will do synchronous or asynchronous message receives. Specify MQ_SESSION_SYNC_RECEIVE or MQ_SESSION_ASYNC_RECEIVE.

If the session is only for producing messages, the receiveMode has no significance. In that case, specify MQ_SESSION_SYNC_RECEIVE to optimize the session's resource use.

sessionHandle

A handle to this session. You will need to pass this handle to the functions you use to manage the session and to create destinations, consumers, and producers associated with this session.

The MQCreateSession function creates a new session and passes back a handle to it in the sessionHandle parameter. The number of sessions you can create for a single connection is limited only by system resources. A session is a single-thread context for producing and consuming messages. You can create multiple producers and consumers for a session, but you are restricted to use them serially. In effect, only a single logical thread of control can use them.

A session with a registered message listener is dedicated to the thread of control that delivers messages to the listener. This means that if you want to send messages, for example, you must create another session with which to do this. The only operations you can perform on a session with a registered listener, is to close the session or the connection.

After you create a session, you can create the producers, consumers, and destinations that use the session context to do their work.

• For a session that is not transacted, use the MQRecoverSession function to restart message delivery with the last unacknowledged message.

• For a session that is transacted, use the MQRollBackSession function to roll back any messages that were delivered within this transaction. Use the MQCommitSession function to commit all messages associated with this transaction.

• For a session that has acknowledgeMode set to MQ_CLIENT_ACKNOWLEDGE, use the function MQAcknowledgeMessages to acknowledge consumed messages.

• Use the MQCloseSession function to close a session and all its associated producers and consumers. This function also frees memory allocated for the session.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session with which you want to associate this destination.

destinationType

An enum specifying the destination type, either MQ_QUEUE_DESTINATION or MQ_TOPIC_DESTINATION.

destinationHandle

Output parameter for the handle to the newly created temporary destination.

You can use a temporary destination to implement a simple request/reply mechanism. When you pass the handle of a temporary destination to the MQSetMessageReplyTo function, the consumer of the message can use that handle as the destination to which it sends a reply.

Temporary destinations are explicitly created by client applications; they are deleted when the connection is closed. They are maintained (and named) by the broker only for the duration of the connection for which they are created. Temporary destinations are system-generated uniquely for their connection and only their own connection is allowed to create message consumers for them.

For more information, see "The Request-Reply Pattern" in Oracle GlassFish Server Message Queue Technical Overview and "Managing a Broker ", "Configuring and Managing Connection Services" and "Managing Administered Objects" in Oracle GlassFish Server Message Queue Administration Guide.

Common Errors

MQ_INVALID_DESTINATION_TYPE
MQ_SESSION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

Output parameter for the handle to the new, empty message.

After you obtain the handle to a text message, you can use this handle to define its content with the MQSetBytesMessageBytesMQSetStringProperty function, to set its headers with the MQSetMessageHeaders function, and to set its properties with the MQSetMessageProperties function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection to which this session belongs. This handle is passed back to you by the MQGetXAConnection function. You can create multiple sessions on a single connection.

receiveMode

An enumeration specifying whether this session will do synchronous or asynchronous message receives. Specify MQ_SESSION_SYNC_RECEIVE or MQ_SESSION_ASYNC_RECEIVE.

If the session is only for producing messages, the receiveMode has no significance. In that case, specify MQ_SESSION_SYNC_RECEIVE to optimize the session's resource use.

beforeMessageListener

A callback function before asynchronous message delivery.

afterMessageListener

A callback function after asynchronous message delivery.

callbackData

A data pointer to be passed to the beforeDelivery and afterDelivery functions.

sessionHandle

A handle to this session. You will need to pass this handle to the functions you use to manage the session and to create destinations, consumers, and producers associated with this session.

If receiveMode is MQ_SESSION_SYNC_RECEIVE, pass NULL for beforeMessageListener, afterMessageListener, and callbackData.

The MQCreateXASession function creates a new distributed transaction (XA) session. The connectionHandle must be a XA connection handle.

An XA session is the same as a regular session created by MQCreateSession (see MQCreateSession) except:

• An XA session is always XA transacted and the distributed transaction is managed by a X/Open distributed transaction manager. MQCommitSession and MQRollbackSession should not be called on a XA session.

• Sending/receiving messages with an XA session must be done in an XA transaction.

• If receiveMode is MQ_SESSION_ASYNC_RECEIVE, callback functions beforeMessageListener and afterMessageListener must be specified. beforeMessageListener will be called by the C-API runtime before it calls the messageListener callback; afterMessageListener will be called by the C-API runtime after it calls the messageListener callback.

  The beforeMessageListener and afterMessageListener functions are provided to the application to associate and disassociate the C-API runtime calling thread with an XA transaction, to demarcate XA transactions, and to set appropriate application association context to the calling thread if the application's distributed transaction processing environment requires that.

  During normal processing, the C-API runtime:

  1. Calls the beforeMessageListener function.

  2. Processes the message, calling the messageListener function.

  3. Calls the afterMessageListener function.

  However, errors can alter this processing sequence:

  • If the beforeMessageListener function returns an error (a value other than MQ_OK), the C-API runtime logs a warning message containing the error code and then stops processing the message. It does not call messageListener or afterMessageListener.

  • If the attempt to call messageListener fails, or if message acknowledgement fails, the C-API runtime passes the appropriate error code to afterMessageListener.

  • If the messageListener function returns an error, the C-API runtime logs a warning containing the error code and then passes the MQ_CALLBACK_RUNTIME_ERROR error to afterMessageListener, regardless of the actual error code returned.

  • If the afterMessageListener function returns an error, the C-API runtime logs a warning containing the error code.

  Even if an error occurs, the callbackData parameter is passed to the beforeMessageListener and afterMessageListener functions unchanged.

Common Errors

MQ_NOT_XA_CONNECTION
MQ_INVALID_RECEIVE_MODE
MQ_BROKER_CONNECTION_CLOSED
MQ_COULD_NOT_CREATE_THREAD

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

A handle to the connection you want to free.

You must call this function after you have closed the connection with the MQCloseConnection() function and after all of the application threads associated with this connection and its dependent sessions, producers, and consumers have returned.

You must not call this function while an application thread is active in a library function associated with this connection or one of its dependent sessions, producers, consumers, and destinations.

Calling this function does not release resources held by a message or a destination associated with this connection. You must free memory allocated for a message or a destination by explicitly calling the MQFreeMessage or the MQFreeDestination function.

Common Errors

MQ_STATUS_CONNECTION_NOT_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

destinationHandle

A handle to the destination you want to free.

Calling the MQCloseConnection, MQCloseSession or MQFreeConnection function does not automatically free destinations created for the connection or for the session.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to the message you want to free.

Calling the MQCloseCOnnection, MQCloseSession or MQFreeConnection function does not automatically free messages associated with that connection or session.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object you want to free.

You should not free a properties handle if the properties handle passed to a function becomes invalid on its return. If you do, you will get an error.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

statusString

An MQString returned by the MQGetStatusString function or by the MQGetErrorTrace function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session whose acknowledgement mode you want to determine.

ackMode

Output parameter for the ackMode. The ackMode returned can be one of four enumeration values. See Acknowledge Modes for information about these values.

If you want to change the acknowledge mode, you need to create another session with the desired mode.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the specified key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message that is passed to you when you receive a message.

messageBytes

Output parameter that contains the start address of the bytes that constitute the body of this bytes message.

messageBytesSize

Output parameter that contains the size of the message body in bytes.

After you obtain the handle to a message, you can use the MQGetMessageType function to determine its type and, if the type is MQ_BYTES_MESSAGE, you can use the MQGetBytesMessageBytes function to retrieve the message bytes (message body).

The bytes message passed to you by this function is not a copy. You should not modify the bytes or attempt to free it.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

A handle to a connection.

propertiesHandle

A handle to the properties of the connection.

The caller is responsible to free the returned connection properties by calling MQFreeProperties.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

destinationHandle

A handle to the destination whose name you want to know.

destinationName

Output parameter for the destination name. The returned destinationName is a copy which the caller is responsible for freeing by calling the MQFreeString() function

Use the MQGetDestinationName function to get the name of a destination. This might be useful for applications that want to do some message processing based on the destination name.

This function is useful when using the Reply-To pattern. You can use the MQGetMessageReplyTo function to obtain a handle to the destination where the message should be sent. You can then use the MQGetDestinationName to get the name of that destination.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

destinationHandle

A handle to the destination whose type you want to know.

destinationType

Output parameter for the destination type; either MQ_QUEUE_DESTINATION or MQ_TOPIC_DESTINATION.

Use the MQGetDestinationType function to determine the type of a destination: queue or topic. There may be times when you do not know the type of the destination to which you are replying: for example, when you get a handle from the MQGetMessageReplyTo function. Because the semantics of queue and topic destinations differ, you need to determine the type of a destination in order to reply appropriately.

Once you have created a destination with a specified type, you cannot change the type dynamically. If you want to change the type of a destination, you need to free the destination using the MQFreeDestination function and then to create a new destination, with the desired type, using the MQCreateDestination or the MQCreateTemporaryDestination function.

MQGetFloat32Property

The MQGetFloat32Property function passes back the value of the MQFloat32 property for the specified key.

MQGetFloat32Property(const MQPropertiesHandle propertiesHandle,
                           ConstMQString key,
                           MQFloat32 * value);

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the specified key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter for the property value.

Common Errors

MQ_NOT_FOUND
MQ_INVALID_TYPE_CONVERSION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

The message handle.

headersHandle

Output parameter for the handle to the message header properties.

The MQGetMessageHeaders function passes back a handle to the message headers. The message header includes the fields described in Table 4-5. Note that most of the fields are set by the send function; the client can optionally set only two of these fields for sending messages.

MQString

MQString

MQBool

MQInt64

MQInt8

MQInt64

MQString

MQBool

You are responsible for freeing the headersHandle after you are done with it. Use the MQFreeProperties function to free the handle.

Use the MQSetBytesMessageBytes MQGetMessageProperties function to determine whether any application-defined properties were set for this message and to find out their value.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message whose properties you want to get.

propertiesHandle

Output parameter for the handle to the message properties.

The MQGetMessageProperties function allows you to get application-defined properties for a message. Properties allow an application, via message selectors, to select or filter messages on its behalf using application-specific criteria. Having obtained the handle, you can either use one of the MQGet...Property functions to get a value (if you know the key name) or you can iterate through the properties using the MQPropertiesKeyIterationStart function.

You will need to call the function MQFreeProperties() to free the resources associated with this handle after you are done using it.

Common Errors

MQ_NO_MESSAGE_PROPERTIES

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message expecting a reply. This is the handle that is passed back to you when you receive the message.

destinationHandle

Output parameter for the handle to the reply destination.

The sender uses the MQSetMessageReplyTo function to specify a destination where replies to the message can be sent. This can be a normal destination or a temporary destination. The receiving client can pass the message handle to the MQGetMessageReplyTo function and determine whether a destination for replies has been set up for the message by the sender and what that destination is. The consumer of the message can then use that handle as the destination to which it sends a reply.

You might need to call the MQGetDestinationType function to determine the type of the destination whose handle is returned to you: queue or topic so that you can set up your reply appropriately.

The advantage of setting up a temporary destination for replies is that Message Queue automatically creates a physical destination for you, rather than your having to have the administrator create one, when the broker's auto.create.destination property is turned off.

You are responsible for freeing the destination handle by calling the function MQFreeDestination.()

Common Errors

MQ_NO_REPLY_TO_DESTINATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message whose type you want to determine.

messageType

Output parameter that contains the message type: MQ_TEXT_MESSAGE or MQ_BYTES_MESSAGE.

After you obtain the handle to a message, you can determine the type of the message using the MQGetMessageType function. Having determined its type, you can use the MQGetTextMessageText function or the MQGetBytesMessageBytes function to obtain the message content.

Note that other message types might be added in the future. You should not design your code so that it only expects two possible message types.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection that you want the information about.

propertiesHandle

Output parameter that contains the properties handle.

The Message Queue product you are using is identified by a name and a version number. For example: "Sun Java(tm) System Message Queue 3.5.1." The version number consists of a major, minor, micro, and update release component. For example, the major part of version 3.5.1. is 3; the minor is 5; and the micro is 1. For release 3.7 UR1, the major part is 3; the minor is 7; and the update release is 1.

The name and version information of the Message Queue product are set by the library when you call the MQCreateConnection function to create the connection. You can retrieve this information by calling the MQGetMetaData function and passing a properties handle. Once the function returns and passes the handle back, you can use one of the MQGet...Properties functions to determine the value of a property (key). These properties are described in Table 4-2.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle that you want to access.

key

The property key for which you want to get the type of the property value.

propertyType

Output parameter for the type of the property value.

Use the appropriate MQGet...Property function to find the value of the specified property key.

Common Errors

MQ_NOT_FOUND

Parameters

status

The status returned by any Message Queue function that returns an MQStatus.

Having found that a Message Queue function has not returned successfully, you can determine the reason by passing the return status. This function will return the error code associated with the specified status. These codes are listed and described in Message Queue C API Error Codes.

Some functions might return an MQStatus that contains an NSPR or NSS library error code instead of a Message Queue error code when they fail. For NSPR and NSS library error codes, the MQGetStatusString function will return the symbolic name of the NSPR or NSS library error code. See NSPR and NSS public documentation for NSPR and NSS error code symbols and their interpretation at the following locations:

• For NSPR error codes, see the "NSPR Error Handling" chapter at the following location: http://www.mozilla.org/projects/nspr/reference/html/index.html.

• For SSL and SEC error codes, see the "NSS and SSL Error Codes" chapter at the following location: http://www.mozilla.org/projects/security/pki/nss/ref/ssl/.

To obtain an MQString that describes the error, use the MQGetStatusString function. To get an error trace associated with the error, use the MQGetErrorTrace function.

Parameters

status

The status returned by any Message Queue function that returns an MQStatus.

Having found that a Message Queue function has not returned successfully, you can determine the reason why by passing the return status. This function will return an MQString describing the error associated with the specified status.

To obtain the error code for the specified status, use the MQGetStatusCode function. To get an error trace associated with the error, use the MQGetErrorTrace function.

You must call the MQFreeString function to free the MQString returned by the MQGetStatusString function when you are done.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle for the key you want to get.

key

The name of a property key.

value

Output parameter that points to the value of the specified key

You should not modify or attempt to free the value returned.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to an MQ_TEXT_MESSAGE message that is passed to you when you receive a message.

messageText

The output parameter that points to the message text.

After you obtain the handle to a message, you can use the MQGetMessageType () function to determine its type and, if the type is text, you can use the MQGetTextMessageText() function to retrieve the message text.

The MQString passed to you by this function is not a copy. You should not modify the bytes or attempt to free it.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

A handle to an XA connection.

MQCloseConnection should not be called on an XA connection handle.

Common Errors

MQ_STATUS_INVALID_HANDLE

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

certificateDatabasePath

An MQString specifying the path to the directory that contains the certificate data base files.

The Message Queue C-API library uses NSS to support the SSL transport protocol between the Message Queue C client and the Message Queue broker.

Before you connect to a broker over SSL, you must initialize the SSL library by calling the MQInitializeSSL function. If your client uses secure connections, you must call this function once and only once before you create any connection, even if that connection is not an SSL connection.

The certificateDatabasePath parameter specifies the path to the NSS certificate database where cert7.db or cert8.db , key3.db, and secmod.db files are located.

The work required to configure secure communication includes initializing the SSL library using the MQInitializeSSL function. There may be additional work, depending on whether the broker is trusted (the default setting) and on whether you want to provide an additional means of verification if the broker is not trusted and the initial attempt to create a secure connection fails. For complete information see Working With Secure Connections.

You must take care if the client application using secure Message Queue connections uses NSS (for other purposes) directly as well and does NSS initialization. For additional information, see Coordinating NSS Initialization.

Common Errors

MQ_INCOMPATIBLE_LIBRARY
MQ_SSL_ALREADY_INITIALIZED
MQ_SSL_INIT_ERROR

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle whose contents you want to access.

key

The output parameter for the next properties key in the iteration. You should not attempt to modify or free it.

Return Value

MQBool

Parameters

propertiesHandle

A properties handle that you want to access.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A properties handle that you want to access.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

consumerHandle

The handle to the message consumer. This handle is passed back to you when you create a synchronous message consumer.

messageHandle

Output parameter for the handle to the message to be received. You are responsible for freeing the message handle when you are done by calling the MQFreeMessage() function.

This function can only be called if the session is created with receive mode MQ_SESSION_SYNC_RECEIVE. The MQReceiveMessageNoWait function passes a handle back to you in the messageHandle parameter if there is a message arrived for the consumer specified by the consumerHandle parameter. If there is no message for the consumer, the function returns immediately with an error.

When you create a session, you specify one of several acknowledge modes for that session; these are described in Acknowledge Modes. If you specify MQ_CLIENT_ACKNOWLEDGE as the acknowledge mode for the session, you must explicitly call the MQAcknowledgeMessages function to acknowledge messages that you have received. For more information, see the description of the function MQAcknowledgeMessages.

Because distributed applications involve greater processing time, such an application might not behave as expected if it were run locally. For example, calling the MQReceiveMessageNoWait function might return MQ_NO_MESSAGE even when there is a message available to be retrieved.

If a client connects to the broker and immediately calls the MQReceiveMessageNoWait , it is possible that the message queued for the consuming client is in the process of being transmitted from the broker to the client. The client runtime has no knowledge of what is on the broker, so when it sees that there is no message available on the client's internal queue, it returns with MQ_NO_MESSAGE .

You can avoid this problem by having your client use one of the synchronous receive methods that specifies a timeout interval.

You can use the MQReceiveMessageWait function if you want the receive function to block while waiting for a message to arrive. You can use the MQReceiveMessageWithTimeout function to wait for a specified time for a message to arrive.

Common Errors

MQ_NOT_SYNC_RECEIVE_MODE
MQ_CONCURRENT_ACCESS
MQ_NO_MESSAGE
MQ_CONSUMER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

consumerHandle

The handle to the message consumer. This handle is passed back to you when you create a synchronous message consumer.

messageHandle

Output parameter for the handle to the message to be received. You are responsible for freeing the message handle when you are done by calling the MQFreeMessage() function.

This function can only be called if the session is created with receive mode MQ_SESSION_SYNC_RECEIVE. The MQReceiveMessageWait function passes a handle back to you in the messageHandle parameter if there is a message arrived for the consumer specified by the consumerHandle parameter. If there is no message for the consumer, the function blocks until a message is delivered.

When you create a session, you specify one of several acknowledge modes for that session; these are described in Acknowledge Modes. If you specify MQ_CLIENT_ACKNOWLEDGE as the acknowledge mode for the session, you must explicitly call the MQAcknowledgeMessages function to acknowledge messages that you have received. For more information, see the description of the function MQAcknowledgeMessages.

You can use the MQReceiveMessageNoWait function instead if you do not want to block while waiting for a message to arrive. You can use the function MQReceiveMessageWithTimeout to wait for a specified time for a message to arrive.

Common Errors

MQ_NOT_SYNC_RECEIVE_MODE
MQ_CONCURRENT_ACCESS
MQ_CONSUMER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

consumerHandle

The handle to the message consumer. This handle is passed back to you when you create a synchronous message consumer.

timeoutMilliseconds

The number of milliseconds to wait for a message to arrive.

messageHandle

Output parameter for the handle to the message to be received. You are responsible for freeing the message handle when you are done by calling the MQFreeMessage() function.

This function can only be called if the session is created with receive mode MQ_SESSION_SYNC_RECEIVE. The MQReceiveMessageWithTimeout function passes a handle back to you in the messageHandle parameter if a message arrives for the consumer specified by the consumerHandle parameter in the amount of time specified by the timoutMilliseconds parameter. If no message arrives within the specified amount of time, the function returns an error.

When you create a session, you specify one of several acknowledge modes for that session; these are described in Acknowledge Modes. If you specify MQ_CLIENT_ACKNOWLEDGE as the acknowledge mode for the session, you must explicitly call the MQAcknowledgeMessages function to acknowledge messages that you have received. For more information, see the description of the function MQAcknowledgeMessages.

You can use the MQReceiveMessageWait function to block while waiting for a message to arrive. You can use the MQReceiveMessageNoWait() function if you do not want to wait for the message to arrive.

Common Errors

MQ_NOT_SYNC_RECEIVE_MODE
MQ_CONCURRENT_ACCESS
MQ_TIMEOUT_EXPIRED
MQ_CONSUMER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session that you want to recover.

You can only call this function for sessions that are not transacted. To rollback message delivery for a transacted session, use the MQRollBackSession () function. This function may be most useful if you use the MQ_CLIENT_ACKNOWELDGE mode.

All consumers deliver messages in a serial order. Acknowledging a received message automatically acknowledges all messages that have been delivered to the client.

Restarting a session causes it to take the following actions:

• Stop message delivery in this session.

• Mark all messages that might have been delivered but not acknowledged as redelivered.

• Restart the delivery sequence including all unacknowledged messages that had been previously delivered. (Redelivered messages might not be delivered in their original delivery order.)

Common Errors

MQ_TRANSACTED_SESSION
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the transacted session that you want to roll back.

A transacted session groups messages into an atomic unit known as a transaction. As messages are produced or consumed within a transaction, the broker tracks the various sends and receives, completing these operations only when you call the MQCommitSession() function.

If a send or receive operation fails, you must use the MQRollBackSession function to roll back the entire transaction. This means that those messages that have been sent are destroyed and those messages that have been consumed are automatically recovered.

Common Errors

MQ_NOT_TRANSACTED_SESSION
MQ_CONCURRENT_ACCESS
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_XA_SESSION_IN_PROGRESS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

producerHandle

The handle to the producer sending this message. This handle is passed back to you by the MQCreateMessageProducerForDestination function.

messageHandle

A handle to the message you want to send.

The MQSendMessage function sends the specified message on behalf of the specified producer to the destination associated with the message producer. If you use this function to send a message, the following message header fields are set to default values when the send completes.

• MQ_PERSISTENT_HEADER_PROPERTY will be set to MQ_PERSISTENT_DELIVERY.

  This means that the calling thread will be blocked, waiting for the broker to acknowledge receipt of your messages, unless you set the connection property MQ_ACK_ON_PRODUCE_PROPERTY to MQ_FALSE.

• MQ_PRIORITY_HEADER_PROPERTY will be set to 4.

• MQ_EXPIRATION_HEADER_PROPERTY will be set to 0, which means that the message will never expire.

If you set those message properties, they will be ignored when a message is sent. To send a message with these properties set to different values, you can use the MQSendMessageExt function to specify different values for these properties.

You cannot use this function with a producer that is created without a specified destination.

Common Errors

MQ_PRODUCER_NO_DESTINATION
MQ_PRODUCER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

producerHandle

The handle to the producer sending this message. This handle is passed back to you by the MQCreateMessageProducerForDestination function.

messageHandle

A handle to the message you want to send.

msgDeliveryMode

An enum

MQ_PERSISTENT_DELIVERY
MQ_NONPERSISTENT_DELIVERY

msgPriority

A integer value of 0 through 9; 0 being the lowest priority and 9 the highest.

msgTimeToLive

An integer value specifying in milliseconds how long the message will live before it expires. When a message is sent, its expiration time is calculated as the sum of its time-to-live value and current GMT. A value of 0 indicates that he message will never expire.

The MQSendMessageExt function sends the specified message on behalf of the specified producer to the destination associated with the message producer. Use this function if you want to change the default values for the message header properties as shown in the next table.

Property

Default value

msgDeliveryMode

MQ_PERSISTENT_DELIVERY

msgPriority

4

msgTimeToLive

0, meaning no expiration limit

If you set these message headers using the MQSetMessageHeaders function before the send, they will be ignored when the message is sent. When the send completes, these message headers hold the values that are set by the send.

You cannot use this function with a producer that is created without a specified destination.

You can set the broker property MQ_ACK_ON_PRODUCE_PROPERTY to make sure that the message has reached its destination on the broker:

• By default, the broker acknowledges receiving persistent messages only.

• If you set the property to MQ_TRUE, the broker acknowledges receipt of all messages (persistent and non-persistent) from the producing client.

• If you set the property to MQ_FALSE, the broker does not acknowledge receipt of any message (persistent or non-persistent) from the producing client.

Note that "acknowledgement" in this case is not programmatic but internally implemented. That is, the client thread is blocked and does not return until the broker acknowledges messages it receives from the producing client.

Common Errors

MQ_PRODUCER_NO_DESTINATION
MQ_INVALID_PRIORITY
MQ_INVALID_DELIVERY_MODE
MQ_PRODUCER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

producerHandle

The handle to the producer sending this message. This handle is passed back to you by the MQCreateMessageProducer function.

messageHandle

A handle to the message you want to send.

destinationHandle

A handle to the destination where you want to send the message.

The MQSendMessageToDestination function sends the specified message on behalf of the specified producer to the specified destination. If you use this function to send a message, the following message header fields are set as follows when the send completes.

• MQ_PERSISTENT_HEADER_PROPERTY will be set to MQ_PERSISTENT_DELIVERY.

  This means that the caller will be blocked, waiting for broker acknowledgement for the receipt of your messages unless you set the connection property MQ_ACK_ON_PRODUCE_PROPERTY to MQ_FALSE.

• MQ_PRIORITY_HEADER_PROPERTY will be set to 4.

• MQ_EXPIRATION_HEADER_PROPERTY will be set to 0, which means that the message will never expire.

To send a message with these properties set to different values, you must use the MQSendMessageToDestinationExt function, which allows you to set these three header properties.

If you set these message headers using the MQSetMessageHeaders function before the send, they will be ignored when the message is sent. When the send completes, these message headers hold the values that are set by the send.

You cannot use this function with a producer that is created with a specified destination.

Common Errors

MQ_PRODUCER_HAS_DEFAULT_DESTINATION
MQ_PRODUCER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

producerHandle

The handle to the producer sending this message. This handle is passed back to you when you call the MQCreateMessageProducer function.

messageHandle

A handle to the message you want to send.

destinationHandle

A handle to the destination where you want to send the message.

msgDeliveryMode

An enum of either MQ_PERSISTENT_DELIVERY or MQ_NONPERSISTENT_DELIVERY.

msgPriority

A integer value of 0 through 9; 0 being the lowest priority and 9 the highest.

msgTimeToLive

An integer value specifying in milliseconds how long the message will live before it expires. When a message is sent, its expiration time is calculated as the sum of its time-to-live value and current GMT. A value of 0 indicates that the message will never expire.

The MQSendMessageToDestinationExt function sends the specified message on behalf of the specified producer to the specified destination. Use this function if you want to change the default values for the message header properties as shown below:

Property

Default value

msgDeliveryMode

MQ_PERSISTENT_DELIVERY

msgPriority

4

msgTimeToLive

0, meaning no expiration limit

If these default values suit you, you can use the MQSendMessageToDestination function to send the message.

You cannot use this function with a producer that is created with a specified destination.

You can set the broker property MQ_ACK_ON_PRODUCE_PROPERTY to make sure that the message has reached its destination on the broker:

• By default, the broker acknowledges receiving persistent messages only from the producing client.

• If you set the property to MQ_TRUE, the broker acknowledges receipt of all messages (persistent and non-persistent) from the producing client.

• If you set the property to MQ_FALSE, the broker does not acknowledge receipt of any message (persistent or non-persistent) from the producing client.

Note that "acknowledgement" in this case is not programmatic but internally implemented. That is, the client thread is blocked and does not return until the broker acknowledges messages it receives.

Common Errors

MQ_PRODUCER_HAS_DEFAULT_DESTINATION
MQ_INVALID_PRIORITY
MQ_INVALID_DELIVERY_MODE
MQ_PRODUCER_CLOSED
MQ_SESSION_CLOSED
MQ_BROKER_CONNECTION_CLOSED
MQ_THREAD_OUTSIDE_XA_TRANSACTION
MQ_XA_SESSION_NO_TRANSATION

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of the property key. The library makes a copy of the property key.

value

The MQBool property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to an MQ_BYTES_MESSAGE message whose body you want to set.

messageBytes

A pointer to the bytes you want to set. The library makes a copy of the message bytes.

messageSize

An integer specifying the number of bytes in messageBytes .

After you obtain the handle to a bytes message from MQCreateBytesMessage , you can use this handle to define its body with the MQSetBytesMessageBytes function, to set its application-defined properties with the MQSetMessageProperties function, and to set certain message headers with the MQSetMessageHeaders function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of a property key. The library makes a copy of the property key.

value

The MQFloat32 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of a property key. The library makes a copy of the property key.

value

The MQFloat64 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of a property key. The library makes a copy of the property key.

value

The MQInt16 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of a property key. The library makes a copy of the property key.

value

The MQInt32 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set.

key

The name of a property key. The library makes a copy of the property key.

value

The MQInt64 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set

key

The name of a property key. The library makes a copy of the property key.

value

The MQInt8 property value.

Common Errors

MQ_HASH_VALUE_ALREADY_EXISTS

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message.

headersHandle

A handle to the header properties object. This handle will be invalid after the function returns successfully.

After you have created a properties handle and defined values for message header properties using one of the MQSet...Property functions, you can pass the handle to the MQSetMessageHeaders function to define the message header properties.

The message header properties are described in the table below. For sending messages, the client can only set two of these: the correlation ID property and the message type property. The client is not required to set these; they are provided for the client's convenience. For example, the client can use the key MQ_MESSAGE_TYPE_HEADER_PROPERTY to sort incoming messages according to application-defined message types.

MQ_CORRELATION_ID_HEADER_PROPERTY

MQString

MQ_MESSAGE_TYPE_HEADER_PROPERTY

MQString

MQ_PERSISTENT_HEADER_PROPERTY

MQBool

MQ_EXPIRATION_HEADER_PROPERTY

MQInt64

MQ_PRIORITY_HEADER_PROPERTY

MQInt8

MQ_TIMESTAMP_HEADER_PROPERTY

MQInt64

MQ_MESSAGE_ID_HEADER_PROPERTY

MQString

MQ_REDELIVERED_HEADER_PROPERTY

MQBool

Header properties that are not specified in the headersHandle are not affected. You cannot use this function to override header properties that are set by the broker or the send function. The header properties for persistence, expiration, and priority (MQSetMessageHeaders)() are set to default values if the user called the MQSendMessage() or MQSendMessageToDestination() function, or they are set to values the user specifies (in parameters) if the user called the MQSendMessageExt () or the MQSendMessageToDestinationExt() function.

Use the MQSetBytesMessageBytes() function or the MQSetTextMessageText() function to set the body of a message. Use the MQSetMessageProperties function to set the application-defined properties of a message that are not part of the header.

Common Errors

MQ_PROPERTY_WRONG_VALUE_TYPE

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message whose application-defined properties you want to set.

propertiesHandle

A handle to a properties object that you have created and set using one of the set property functions. This handle is invalid after the function returns successfully.

After you obtain the handle to a message, you can use this handle to define its body with the MQSetBytesMessageBytes() or MQSetTextMessageText() function, and to set its header properties with the MQSetMessageHeaders() function.

Property values are set prior to sending a message. The MQSetMessageProperties function allows you to set application-defined properties for a message. For example, application-defined properties allow an application, via message selectors, to select or filter, messages on its behalf using application-specific criteria.

You define the message properties and their values using the MQCreateProperties function to create a properties object, then you use one of the set property functions to define each key and value in it. See Working With Properties for more information.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message expecting a reply.

destinationHandle

The destination to which the reply is sent. Usually this is a handle to a destination that you created using the MQCreateDestination function or the function MQCreateTemporaryDestination. The handle is still valid when this function returns.

The sender uses the MQSetMessageReply function to specify a destination where replies to the message can be sent. This can be a normal destination or a temporary destination. The receiver of a message can use the MQGetMessageReplyTo function to determine whether a sender has set up a destination where replies are to be sent. The advantage of setting up a temporary destination for replies is that Message Queue automatically creates a physical destination for you, rather than your having to have the administrator create one if the broker's auto_create_destination property is turned off.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

propertiesHandle

A handle to the properties object whose property value for the specified key you want to set. You get this handle from the MQCreateProperties () function.

key

The name of a property key. The library makes a copy of the property key

value

The property value to set. The library makes a copy of the value.

The library makes a copy of the property key and also makes a copy of the value.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

messageHandle

A handle to a message whose text body you want to set.

messageText

An MQString specifying the message text. The library makes a copy of the message text.

After you obtain the handle to a text message, you can use this handle to define its body with the MQSetTextMessageText() function. You can set its application-defined properties with the MQSetMessageProperties function, and you can set certain message headers with the MQSetMessageHeaders function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection that you want to start. This handle is the handle that is created and passed back to you by the MQCreateConnection function.

When a connection is created it is in stopped mode. Until you call this function, messages are not delivered to any consumers. Call this function to start a connection or to restart a connection that has been stopped with the MQStopConnection() function. To create an asynchronous consumer, you could have the connection in stopped mode, and start or restart the connection after you have set up the asynchronous message consumer.

Use the MQCloseConnection function to close a connection, and then use the MQFreeConnection function to free the memory allocated to the connection.

Common Errors

MQ_BROKER_CONNECTION_CLOSED

Parameters

status

The status returned by any Message Queue function that returns an MQStatus.

Nearly all Message Queue C library functions return an MQStatus. You can pass this status result to the MQStatusIsError function to determine whether your call succeeded. If the MQStatusIsError function returns MQ_TRUE(=1), the function failed; if it returns MQ_FALSE(=0), the function returned successfully.

If the MQStatusIsError returns MQ_TRUE, you can get more information about the error that occurred by passing the status returned to the MQGetStatusCode function. This function will return the error code associated with the specified status.

To obtain an MQString that describes the error, use the MQGetStatusString function. To get an error trace associated with the error, use the MQGetErrorTrace function.

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

connectionHandle

The handle to the connection that you want to stop. This handle is passed back to you by the MQCreateConnection function.

You can restart message delivery by calling the MQStartConnection function. When the connection has stopped, delivery to all the connection's message consumers is inhibited: synchronous receives block, and messages are not delivered to message listeners. This call blocks until receives and/or message listeners in progress have completed.

You should not call MQStopConnection in a message listener callback function.

Use the MQCloseConnection function to close a connection, and then use the MQFreeConnection function to free the memory allocated to the connection.

Common Errors

Return Value

MQStatus. See the MQStatusIsError function for more information.

Parameters

sessionHandle

The handle to the session to which this consumer belongs. This handle is created and passed back to you by the MQCreateSession function.

durableName

An MQString specifying the name of the durable subscriber.

When you call the MQUnsubscribeDurableMessageConsumer function, the client runtime instructs the broker to delete the state information that the broker maintains for this consumer. If you try to delete a durable consumer while it has an active topic subscriber or while a received message has not been acknowledged in the session, you will get an error. You should only unsubscribe a durable message consumer after closing it.

Common Errors