Restriction: This topic does not apply to AMODE 64.
z/OS® XL C/C++ under CICS Transaction Server for z/OS (CICS
TS) supports only three kinds of I/O:
- CICS I/O
- z/OS XL C/C++ applications can access the CICS I/O commands through
the CICS command level interface.
- Files
- Memory files are the only type of file that z/OS XL C/C++ supports
under CICS. Hiperspace™ files are not supported.
VSAM files can be accessed through the CICS command level interface.
- CICS data queues
- Under CICS, z/OS XL C/C++ implements the standard output (stdout)
and standard error (stderr) streams as CICS transient data queues.
These data queues must be defined in the CICS Destination Control
table (DCT) by the CICS system administrator before the CICS cold
start. Output from all users' transactions that use stdout (or stderr)
is written to the queue in the order of occurrence.
To help differentiate
the output, place a user's terminal name, the CICS transaction identifier,
and the time at the beginning of each line printed to the queue. The
queues are as follows:
| Stream |
Queue |
|---|
| stdout |
CESO |
| stderr |
CESE |
| stdin |
Not supported |
To access any other queues, you must use the command level
interface.
Note: If you are using the C++ I/O stream
classes, the standard stream cout maps to stdout,
which maps to CESO. The standard stream cerr and clog both
map to stderr, which maps to CESE. The standard stream cin is
not supported under CICS.
For more general information about C++ I/O streaming, see Using the Standard C++ Library I/O Stream Classes. For more detailed information, see Standard C++ Library Reference,
which discusses the Standard C++ I/O stream classes
For information about using z/OS XL C/C++ and z/OS XL C/C++ under CICS TS, see Using the CICS Transaction Server (CICS TS). For information on using wide characters in the CICS
TS environment, see z/OS XL C Support for the double-byte character set.