Using a run function and echoed outputs in memory

When using the Output Target Override - Echo execution command (-OE) with the X option, the output is stored in memory and is not echoed back to the calling map or application. A typical scenario in which this is useful and can serve to optimize performance is when a map has an output that is only used as a scratch card. Tthat is, it is built to be used only by a subsequent output.

For example, if used in a RUN() function:

RUN ("some_map.mmc","-WM -OE1 -OE3X -OE4")

In this example, a memory-based WorkSpace is used and the data for output cards 1 and 4 are echoed back to the rule in which the RUN function is located. All other map settings and input and output card settings for executing this map, such as MapAudit, Century, and so on, would use the settings compiled into some_map.mmc.

This results in the execution of some_map.mmc. The data produced for output card 1 and 4 is concatenated and echoed back to the rule containing the RUN function. The data for output card 3 is not echoed back to the rule because of the use of the X option. Given that output card 1 builds 103910^ABC, output card 3 builds justsomedata, and output card 4 builds 01/23/98, the RUN function returns 103910^ABC01/23/98.

The most common use for this feature of echoed outputs is when the data for an output card is needed only during the execution of the map, perhaps for use on a later output card, and can be discarded after the map has completed execution.

For another example of using an echoed data destination, see the Platform API documentation.