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Refer also to the companion DTAQ_RECEIVE, DTAQ_CLEAR and WATCH_DTAQ activities that allows you to receive data from and to perform other operations on a named data queue.
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| 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 are only available on IBM i servers.
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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_CLEAR, DTAQ_RECEIVE and WATCH_DTAQ activities are available on Windows servers too, but with a reduced feature set and with other restrictions and caveats.
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- The TODTAQLIB parameter is not used and its value will be ignored. (You may use the TODTAQPATH parameter to specify a location for the data queue, if required.)
- Data queues are automatically created when they are first referenced.
- The first reference not only creates the data queue, but also permanently sets the entry size for the data queue according to the value of the DTALEN parameter.
- 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. The files can be manually cleared or deleted by deleting the associated files. Alternatively the DTAQ_CLEAR activity may be used for this purpose.
- The location of the .EDQ and .LDQ data queue storage files is determined by the value of the TODTAQPATH parameter. Refer to that parameter description for further information.
- If you have the Visual LANSA documentation available to you, you can find further information pertinent to the Windows implementation of this and related activities in the description of the SND_TO_DATA_QUEUE built-in function, in the LANSA Technical Reference Guide.
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On Windows servers, the specific implementation used means that the activity is unable to handle certain types of exceptions that may be considered unexceptional in other circumstances. In such cases the processing sequence containing the activity may simply end abnormally without logging diagnostic information in the Processing Sequence log. This behavior differs from most other LANSA Composer activities and from the IBM i implementation of this activity. |
INPUT Parameters:
TODTAQ: Required
This parameter must specify the name of the data queue to which the data is sent.
TODTAQLIB: Optional
When running on IBM i servers, this parameter specifies 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 TODTAQPATH parameter to specify a location for the data queue, if required.
TODTAQPATH: Optional
When running on Windows servers, this parameter specifies the path to the directory in which the data queue .EDQ and .LDQ files are to be stored. If not specified, the default location is determined by the LANSA run-time according to the 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 TODTAQLIB parameter to specify a location for the data queue, if required.
DTALEN: Required
This parameter must specify the number of characters of data to be sent to the data queue. The activity supports data lengths between 1 and 1024 inclusive.
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These parameters specify the data to be sent to the data queue. Each parameter specifies up to 256 bytes of data. The first parameter, SNDDATA is required. The remaining parameters are optional and only need be specified if you are using data queue entries of length greater than 256, 512 and 768 respectively.
OUTPUT Parameters:
There are no output parameters