Formatting other input

Although the data that you format with a RECEIVE MAP command normally comes from a terminal, you can also format data that did not come from a terminal, or that came indirectly.

For example, you might not know which map to use until you receive the input and inspect some part of it. This can happen when you use special hardware features like partitioning or logical device codes, and also in certain logic situations. You might also need to format data that was read from a formatted screen by an intermediate process (without mapping) and later passed to your transaction.

The FROM option of the RECEIVE MAP command addresses these situations. FROM tells BMS that the data has already been read, and only the translation from the native input stream to the input map structure is required.

Because the input has already been read, you need to specify its length if you use FROM, because BMS cannot get this information from the access method, as it does normally. If the data came originally from a RECEIVE command in another task, the length on the RECEIVE MAP FROM command should be the length produced by that original RECEIVE.

For the same reason, you cannot suppress translation to uppercase with the ASIS option when you use FROM. Moreover, BMS does not set EIBAID and EIBCURSR after a RECEIVE FROM command.

And finally, BMS does not know from what device the input came, and it assumes that it was your current principal facility. (You cannot even use RECEIVE FROM without a principal facility, even though no input/output occurs.) If the data came from a different type of device, you have to do the mapping in a transaction with a similar principal facility to get the proper conversion of the input data stream.