The Message Queue Interface overview

Learn about the Message Queue Interface (MQI) components.

The Message Queue Interface consists of the following:

• Calls through which programs can access the queue manager and its facilities
• Structures that programs use to pass data to, and get data from, the queue manager
• Elementary data types for passing data to, and getting data from, the queue manager

IBM MQ for z/OS also supplies:

• Two extra calls through which z/OS batch programs can commit and back out changes.
• Data definition files (sometimes known as copy files, macros, include files, and header files) that define the values of constants supplied with IBM MQ for z/OS.
• Stub programs to link-edit to the applications.
• A suite of sample programs that demonstrate how to use the MQI on the z/OS platform. For further information about these samples, see Use the sample programs for z/OS.

IBM MQ for IBM i also supplies:

• Data definition files (sometimes known as copy files, macros, include files, and header files) that define the values of constants supplied with IBM MQ for IBM i.
• Three stub programs to link-edit to your ILE C, ILE COBOL, and ILE RPG applications.
• A suite of sample programs that demonstrate how to use the MQI on the IBM i platform.

IBM MQ for Windows and IBM MQ on UNIX and Linux systems also supply:

• Calls through which IBM MQ for Windows and IBM MQ on UNIX and Linux systems programs can commit and back out changes.
• Include files that define the values of constants supplied on these platforms.
• Library files to link the applications.
• A suite of sample programs that demonstrate how to use the MQI on these platforms. For further information about these samples, see Use the sample programs on Multiplatforms.
• Sample source and executable code for bindings to external transaction managers.

Use the following links to find out more about the MQI:

• MQI calls
• Sync point calls
• Data conversion, data types, data definitions, and structures
• IBM MQ stub programs and library files
• Parameters common to all the calls
• Specify buffers
• z/OS batch considerations
• UNIX and Linux signal handling

• MQI calls
  Use this information to learn about calls in the Message Queue Interface (MQI).
• Sync point calls
  Use this information to find out about sync point calls on different platforms.
• Data conversion, data types, data definitions, and structures
  Use this information to learn about data conversions, elementary data types, IBM MQ data definitions, and structures when using the Message Queue Interface.
• IBM MQ stub programs and library files
  The stub programs and library files provided are listed here, for each platform.
• Parameters common to all the calls
  There are two types of parameter common to all the calls: handles and return codes.
• Specify buffers
  The queue manager refers to buffers only if they are required. If we do not require a buffer on a call or the buffer is zero in length, we can use a null pointer to a buffer.
• z/OS batch considerations
  z/OS batch programs that call the MQI can be in either supervisor or problem state.
• UNIX and Linux considerations
  Considerations that we need to be aware of.

Parent topic: Writing a procedural application for queuing

Related concepts

• Connect to and disconnecting from a queue manager
• Opening and closing objects
• Put messages on a queue
• Getting messages from a queue
• Inquiring about and setting object attributes
• Committing and backing out units of work
• Starting IBM MQ applications using triggers
• Work with the MQI and clusters
• Use and writing applications on IBM MQ for z/OS
• IMS and IMS bridge applications on IBM MQ for z/OS