Messages

*Messages are stored in a mailboxe called message queue, of object type MSGQ. We can have informational messages (example object not found) or inquiry (example asking for action).

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Information messages can arrive as a simple pictogram at the bottom of the screen (*NOTIFY), or immediately by blocking the screen until an action is taken (*BREAK)

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CRTMSGQ → create a queue

WRKACTJOB SBS(QINTER) → display the screen of connected users

SNDMSG → send message to a user without interrupting

SNDBRKMSG → interrupt a user to display a message

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You can also use an API to send messages → CALL QEZSNDMG or CALL QLZAVXFR or CALL QSMBTTCC or CALL QLZARCAPI

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*DSPMSG → display received messages (default is WRKUSR)

DSPMSG QSYSOPR → display system messages

Execution environment

Objects required for a job execution environment :

***SBSD → subsystem description *JOBQ → job queue *JOBD → job description (parameters for executing a job) CLS → class OUTQ → output queue

Jobs operate within environments known as subsystems, which provide isolation for the jobs. Multiple jobs can run concurrently (simultaneously) within a subsystem, and each job utilizes a memory pool that is allocated to the subsystem.