Advanced CA IDMS Programming Topics › Basic Mode › Reading Data from the Terminal

Reading Data from the Terminal

To transfer data from the terminal screen to program variable storage, issue either a READ TERMINAL or a WRITE THEN READ TERMINAL statement. This transfer begins when the user signals completion of the data entry by pressing an AID key. With 3270-type devices, data can optionally be transferred to the program without user intervention.

Note: WRITE THEN READ TERMINAL is not recommended because it is inherently conversational and holds resources.

Acquiring the Input Buffer

You must dynamically acquire the input buffer for record-element descriptions from the storage pool when the read operation is complete:

• If you specify WAIT, your program must acquire the input buffer by including a GET STORAGE parameter in the READ TERMINAL or WRITE THEN READ TERMINAL request. Your program is also responsible for releasing the acquired storage explicitly with a FREE STORAGE statement. If storage is not explicitly freed, DC releases all acquired buffers when the task terminates.
• If you specify NOWAIT, your program must acquire the input buffer by including a GET STORAGE parameter in the CHECK TERMINAL request.

Where to Define Data

Because storage is acquired by an explicit program request, you must define the associated data-item descriptions in the program's LINKAGE SECTION.