When the system interprets a job's JCL statements, it obtains information about the job's data sets. It stores
this information in the scheduler work area (SWA). When the job runs,
the system develops additional information about the job's data sets,
which it also stores in the SWA. Some of this information is in the
following SWA blocks:
- The job file control block (JFCB)
- The job file control block extension (JFCBX)
Your program can use the SWAREQ macro and the IEFQMREQ macro to read from a
block, write into a block, or obtain the location of a block. The
only SWA blocks that you can access are the ones associated with your
job.
A SWA block can be accessed using one of the following:
- IEFQMREQ reads the SWA information into a buffer that you provide,
or writes information from your buffer into the SWA.
- SWAREQ, instead of actually writing or reading information, only
tells you the location of the SWA block that you are interested in.
Once you know the location, you can examine or change the block directly.
Use IEFQMREQ to access the SWA in programs that have a 24-bit addressing
mode and SWA located above 16 megabytes. See z/OS JES2 Initialization and Tuning Guide or z/OS JES3 Initialization and Tuning Guide for
information on placing SWA above or below 16 megabytes.