MQHasMessage() function
The MQHasMessage() function checks if a message is available from the WMQ.
Syntax
- service_name
- Optional parameter. Refers to the value in the servicename column of the "informix".mqiservice table. If service_name is not specified, IDS.DEFAULT.SERVICE is used as the service. The maximum size of service_name is 48 bytes.
- policy_name
- Optional parameter. Refers to the value in the policyname column of the "informix".mqipolicy table. If policy_name is not specified, IDS.DEFAULT.POLICY is used as the policy. The maximum size of policy_name is 48 bytes.
- correl_id
- Optional parameter. A string containing a correlation identifier to be associated with this message. The correl_id is often specified in request and reply scenarios to associate requests with replies. The maximum size of correl_id is 24 bytes. If not specified, no correlation ID is added to the message.
Usage
You can simulate event processing by using this function and other MQ functions to write custom procedures and run them inside the Scheduler at specified intervals.
The
following table describes how the arguments for the MQHasMessage() function
are interpreted.
| Usage | Argument interpretation |
|---|---|
| MQHasMessage() | No arguments |
| MQHasMessage(arg1) | arg1 = service_name |
| MQHasMessage(arg1, arg2) | arg1 = service_name arg2 = policy_name |
| MQHasMessage(arg1, arg2, arg3) | arg1 = service_name arg2 = policy_name arg3 = correl_id |
Return codes
- 1
- One message or more than one message is present.
- 0
- No Messages are available.
- Error
- The operation was unsuccessful.
Example
This following example reads the message with the following
parameters:
- service_name: "MYSERVICE"
- policy_name: "MYPOLICY"
- correl_id: "TESTS"
begin;
EXECUTE FUNCTION MQHasMessage('MYSERVICE','MYPOLICY', 'TESTS');
commit;