Commarea Storage

Restriction: This topic applies only when the AppMaster Builder AddPack has been installed, and applies only to Windows platforms.

The Commarea is an area of your program generated by Online Express that stores data you pass between programs.

Online Express automatically creates a Commarea; you simply specify the size of the largest record that your program can send or receive in the Extra Commarea Bytes field on the Express Generation Options window. To access this window, from the File menu, select Express Generation Options.

When you generate your program, the following code is generated to create a storage area in Commarea.

    SYM2    $PX-CA-COMPUTE-LEN( savekeybytes, sharedbytes)
    CA05    FILLER
            $PX-CA-SETUP

Where:

Savekeybytes is the number of storage bytes that Online Express calculates for storing record keys when:
- Obtaining records sequentially with the Next action
- Re-reading repeated record block records so that the end user can update and delete them with the Modify and Erase actions.
Online Express calculates the number of savekeybytes as the key length of each window record that can be updated, plus a one-byte flag per key. For scrollable SQL records, Online Express calculates savekeybytes as the length of each Order By column, plus a one-byte flag per key.
Sharedbytes is the number of bytes that you specify for storing data that you pass between programs using the Call, XCTL, XCTL NOTERM, or MSG-SW actions. You can specify any number of bytes. Express stores the sharedbytes in the Commarea data structure PX-USER-COMMAREA.

Alternatively, you can define a Commarea data structure object in your application's Globals folder using the Data Structure Editor. See CA, CA05, and CADS for more information.