DTAQ_CLEAR
This activity clears a named data queue.
Refer also to the companion DTAQ_RECEIVE, DTAQ_SEND and WATCH_DTAQ activities that allows you to send and receive data to and from a named data queue.
Note: Data queues are persistent objects but their data content can be lost or corrupted during a system failure. Backup, recovery and maintenance of data queues used in your LANSA Composer solution is your responsibility – you should make provision for this in your implementation plans.
IBM i Platform Notes
Data queues are a native operating system feature on the IBM i server. The full range of capabilities of this activity may only be available on IBM i servers.
(The implementation of this activity on an IBM i server uses the QCLRDTAQ system API.)
Refer to the description of the DTAQ_SEND activity for more complete IBM i Server Platform Notes relating to the suite of DTAQ activities. Refer to IBM i documentation concerning data queues for further information about the operating system features upon which this activity depends.
Windows Server Platform Notes
Although data queues are a native feature of the IBM i server, this activity and the companion DTAQ_RECEIVE, DTAQ_SEND and WATCH_DTAQ activities are available on Windows servers too, but with a reduced feature set and with other restrictions and caveats.
The following notes and restrictions apply to using this activity on a Windows server:
- The DTAQLIB parameter is not used and its value will be ignored. (You may use the DTAQPATH parameter to specify a location for the data queue, if required.)
- Data queues are stored in pairs of files in the Windows server file system with .EDQ and .LDQ file extensions. The .EDQ file contains the data queue definition and entries. The .LDQ files are used to logically lock the data queue during receive operations. The file names are determined by the LANSA run-time support used by this activity. This activity clears the data queue by deleting these files.
- The location of the .EDQ and .LDQ data queue storage files is determined by the value of the DTAQPATH parameter. Refer to that parameter description for further information.
- Refer to the description of the DTAQ_SEND activity for more complete Windows Server Platform Notes relating to the suite of DTAQ activities.
INPUT Parameters:
DTAQ : Required
This parameter must specify the name of the data queue that is to be cleared.
DTAQLIB: Optional
When running on IBM i servers, this parameter may specify the name of the library containing the data queue. If not specified, a default of *LIBL is used which means the library list is used to locate the named data queue.
When running on a Windows server, this parameter is not used and its value is ignored. You may use the DTAQPATH parameter to specify the location for the data queue, if required.
DTAQPATH: Optional
When running on Windows servers, this parameter may specify the path to the directory in which the data queue .EDQ and .LDQ files are stored. If not specified, the default location is determined by the LANSA run-time according to the effective value of the DPTH= X_RUN parameter.
When running on an IBM i server, this parameter is not used and its value is ignored. You may use the DTAQLIB parameter to specify the location for the data queue, if required.
OUTPUT Parameters:
There are no output parameters