Building logical messages

When you construct a logical message, you must observe a number of rules.

  • You can build only one logical message at a time. If you are routing this message, BMS may create more than one logical message internally, but in terms of content, there is only one. After you complete the message and dispose of it, you can build another in the same task, using different options if you want.
  • Options related to message management must be the same on all commands that build the message. These are:
    • the disposition option: PAGING, TERMINAL, or SET
    • the option governing page formation: ACCUM should be present on all commands or absent on all
    • the identifier for the message in CICS® temporary storage: the REQID option value.
    Switching options mid-message results in the INVREQ condition or, in the case of REQID, the IGREQID condition.
  • The ERASE, ERASEAUP, NLEOM, and FORMFEED options are honored if they are used on any of the BMS commands that contribute to the page.
  • The values of the CURSOR, ACTPARTN, and MSR options for the page are taken from the most recent SEND MAP command, if they are specified there, and from the map if not.
  • The 3270 write control character (WCC) from the most recent SEND MAP command is used. The WCC is assembled from the ALARM, FREEKB, PRINT, FRSET, L40, L64, L80, and HONEOM options in the command whenever any of them is specified. Otherwise, it is built from the same options in the map; options from the command are never mixed with those in the map.
  • The FMHPARMs from all commands used to build the message are included.
  • You can use both SEND MAP and SEND CONTROL commands to build a logical message, as long as the options previously noted are consistent. You can also build a logical message with a combination of SEND TEXT and SEND CONTROL commands. (SEND TEXT is an alternative to SEND MAP for formatting text output, covered in The SEND TEXT command.) However, you cannot mix SEND MAP and SEND TEXT in the same message unless you are using partitions or logical device codes, subjects covered in Partition support and Logical device components respectively.

    There are also two special forms of SEND TEXT which allow combined mapping and text output, but to which other restrictions apply. See SEND TEXT MAPPED and SEND TEXT NOEDIT for details.

  • While you are building a logical message, you can still converse with your terminal. You cannot use BMS commands to write to the terminal unless you are also routing, but you can use BMS RECEIVE MAP commands and terminal control SEND and RECEIVE commands.