Restrictions on the data structure import function

Depending on the z/OS® subsystem and types of programs, restrictions on the size and number of data structures apply. The data structure import function is supported on specific platforms.

Supported platforms for the data structure import function

The data structure import function in the API toolkit is supported on the following platforms:

For COBOL, Windows and Linux® platforms are supported.
The COBOL data structure import function requires the 32-bit version of the OS system libraries. These libraries are not included in some Linux distributions. When these 32-bit libraries are missing, you get an error message that states the import wizard has not found any valid structure declarations. The Eclipse error log includes the following entry:
```
Cannot run program "/opt/IBM/zOS_Explorer/../IBMIMShared/plugins/com.ibm.etools.cobol.linx_7.1.200.201706022205/...."
```
To resolve this issue, see Features that use the COBOL importer do not work properly in the IBM Developer for z Systems documentation.
For PL/I, the Windows platform is supported.

Supported data structures

The following restrictions apply to CICS®:

COMMAREAs are limited to 32 KB.
For channels, you can have any number of containers in a channel and each container can be up to 2 GB.

The following data structure restrictions apply to IMS:

For IMS programs with data structures whose maximum size exceeds 32 KB (32,767 bytes), the programs must handle the decomposition of a large data structure into multiple segments and assembly of multiple segments back into the large data structure. For a sample on how to handle COBOL data structures larger than 32 KB, see Handling large IMS data structures. When you create a service project in the API toolkit, choose IMS Large Data Structure Service as the service type.
Note:
For the maximum size of Enterprise COBOL and PL/I data structures, see the respective documentation:
- Compiler limits for Enterprise COBOL for z/OS 6.1
- Limits for Enterprise PL/I for z/OS 5.1
The actual allowable data structure size depends on how your IMS subsystem is configured and tuned.
The maximum number of data structures is 256.
Variable count of segment structures is not supported. Each segment must be explicitly added.

The following data structure restrictions apply to IBM® MQ:

- Both request and response data structures must be able to fit inside an IBM MQ message, so they must be less than or equal to 100 MB.

For more information about how COBOL and PL/I fields are converted to JSON fields and syntax restrictions, see the following topics: