IBM Z host data format considerations
The following information is about considerations, restrictions, and limitations that apply to the use of IBM Z® host data internal representation.
The CHAR
and FLOAT
compiler
options determine whether IBM 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.)
CICS access
Date and time callable services
You can use the date and time callable services with the IBM Z host data format internal representations. All of the parameters passed to the callable services must be in IBM Z host data format. You cannot mix native and host data internal representations in the same call to a date and time service.
Floating-point overflow exceptions
Due to differences in the limits of floating-point data representations on the Linux® workstation and the IBM Z host, it is possible if FLOAT(BE)
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 IBM 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.
Db2
The IBM Z host data format compiler options can be used with Db2® programs.
Distributed Computing Environment applications
The IBM Z host data format compiler options should not be used with Distributed Computing Environment programs.
File data
- EBCDIC data and hexadecimal binary data can be read from and written to any sequential, relative, or indexed files. No automatic conversion takes place.
- If you are accessing files that contain host data, use the compiler options
BINARY(BE)
,COLLSEQ(EBCDIC)
,CHAR(EBCDIC)
, andFLOAT(BE)
to process binary data, EBCDIC character data and hexadecimal floating-point data that is acquired from these files.
SORT
All of the IBM Z host
data formats except DBCS (USAGE DISPLAY-1
) can
be used as sort keys.