Rational Developer for System z
Enterprise COBOL for z/OS, Version 4.1, Compiler and Runtime Migration Guide


Alternatives to IGZTUNE

If the CSECT produced by assembling the space tuning CSECT IGZETUN is detected in a load module, a warning-level message is issued and the CSECT is not used. Other Language Environment facilities provide storage management capabilities at run time instead of link-edit time.

Note: For applications using IGZETUN, see Using CEEWUCHA for details on how to suppress the warning-level message and the overhead of writing it to the Language Environment MSGFILE.
This is accomplished by using the following five storage management runtime options:
HEAP
Manages heap storage for user data such as WORKING-STORAGE, EXTERNAL data, and EXTERNAL file information.
ANYHEAP
Manages heap storage for use by Language Environment and COBOL library routines, which can be located anywhere and used for control blocks.
BELOWHEAP
Manages heap storage for use by Language Environment and COBOL library routines, which is located below the 16-MB line and used for control blocks and I/O buffers.
STACK
Manages stack storage for use by Language Environment, COBOL data items in the LOCAL-STORAGE SECTION, and COBOL library routines, which can be used for DSAs (dynamic storage areas).
LIBSTACK
Manages stack storage for use by Language Environment and COBOL library routines, which is located below the 16-MB line and used for DSAs.

The RPTSTG runtime option provides the optimum values to use when specifying the storage management options. (You will need to first use the RPTSTG option to generate a report of storage used in your program or run unit. You can then use this report to determine the values that you need to specify in the five Language Environment storage options in order to achieve the space tuning purpose.)

Do not use the values from IGZTUNE when specifying the Language Environment tuning options. These values might not be optimal for tuning storage usage within the Language Environment environment. For recommended Language Environment storage option settings, see Set recommended default Language Environment runtime options.


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