The following are considerations, restrictions, and limitations that apply to the use of System z host data internal representation.
The CHAR and FLOAT compiler options determine whether System z host data format or native data format is used (other than for COMP-5 items or items defined with the NATIVE phrase in the USAGE clause). (The terms host data format and native data format in this information refer to the internal representation of data items.)
There is no System z host data format support for COBOL programs that are translated by the separate or integrated CICS translator and run on TXSeries.
You can use the date and time callable services with the System z host data format internal representations. All of the parameters passed to the callable services must be in System z host data format. You cannot mix native and host data internal representations in the same call to a date and time service.
Due to differences in the limits of floating-point data representations on the AIX workstation and the System z host, it is possible if FLOAT(HEX) is in effect that a floating-point overflow exception could occur during conversion between the two formats. For example, you might receive the following message on the workstation when you run a program that runs successfully on the host:
IWZ053S An overflow occurred on conversion to floating point
To avoid this problem, you must be aware of the maximum floating-point values supported on each platform for the respective data types. The limits are shown in the following table.
| Data type | Maximum workstation value | Maximum System z host value |
|---|---|---|
| COMP-1 | *(2**128 - 2**4)
(approx.*3.4028E+38) |
*(16**63 - 16**57)
(approx.*7.2370E+75) |
| COMP-2 | *(2**1024 - 2**971)
(approx.*1.7977E+308) |
*(16**63 - 16**49)
(approx.*7.2370E+75) |
| * Indicates that the value can be positive or negative. | ||
As shown above, the host can carry a larger COMP-1 value than the workstation and the workstation can carry a larger COMP-2 value than the host.
The System z format of floating-point data items must not be specified for arguments or returning items in INVOKE statements.
The System z host data format compiler options should not be used with Distributed Computing Environment programs.
All of the System z host data formats except DBCS (USAGE DISPLAY-1) can be used as sort keys.
related concepts
Formats for numeric data
related tasks
Coding interoperable data types in COBOL and Java
related references
Compiler options