Inquiring about and setting object attributes

Inquiring about and setting object attributes

Attributes are the properties that define the characteristics of a WebSphere MQ object. They affect the way that a queue manager processes an object. The attributes of each type of WebSphere MQ object are described in detail in the Application Programming Reference.
Some attributes are set when the object is defined, and can be changed only by using the WebSphere MQ commands; an example of such an attribute is the default priority for messages put on a queue. Other attributes are affected by the operation of the queue manager and can change over time; an example is the current depth of a queue.
We can inquire about the current values of most attributes using the MQINQ call. The MQI also provides an MQSET call with which we can change some queue attributes. We cannot use the MQI calls to change the attributes of any other type of object; instead use:

For WebSphere MQ for z/OS

The ALTER operator commands (or the DEFINE commands with the REPLACE option), which are described in the WebSphere MQ Script (MQSC) Command Reference.

For WebSphere MQ for iSeries

The CHGMQMx CL commands, which are described in the WebSphere MQ for iSeries System Administration Guide, or we can use the MQSC facility.

For WebSphere MQ for all other platforms

The MQSC facility, described in the WebSphere MQ Script (MQSC) Command Reference.

The names of the attributes of objects are shown in this book in the form that you use them with the MQINQ and MQSET calls. When you use WebSphere MQ commands to define, alter, or display the attributes, identify the attributes using the keywords shown in the descriptions of the commands in the above books.
Both the MQINQ and the MQSET calls use arrays of selectors to identify those attributes that you want to inquire about or set. There is a selector for each attribute that we can work with. The selector name has a prefix, determined by the nature of the attribute:

MQCA_ These selectors refer to attributes that contain character data (for example, the name of a queue).
MQIA_ These selectors refer to attributes that contain either numeric values (such as CurrentQueueDepth, the number of messages on a queue) or a constant value (such as SyncPoint, whether or not the queue manager supports syncpoints).

Before you use the MQINQ or MQSET calls your application must be connected to the queue manager, and use the MQOPEN call to open the object for setting or inquiring about attributes. These operations are described in Connecting to and disconnecting from a queue manager and Opening and closing objects.

Inquiring about the attributes of an object

Some cases where the MQINQ call fails

Set queue attributes

Parent topic:
Application Programming Guide

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MQCA_	These selectors refer to attributes that contain character data (for example, the name of a queue).
MQIA_	These selectors refer to attributes that contain either numeric values (such as CurrentQueueDepth, the number of messages on a queue) or a constant value (such as SyncPoint, whether or not the queue manager supports syncpoints).