Performing VSAM I/O operations
This topic outlines the use of Virtual Storage Access
Method (VSAM) data sets in z/OS® XL C/C++. Three
I/O processing modes for VSAM data sets are available in z/OS XL C/C++:
- Record
- Text Stream
- Binary Stream
Because VSAM is a record-based access method, record mode is the logical processing mode and is specified by coding the type=record keyword parameter on the fopen() function call. z/OS XL C/C++ also provides limited support for VSAM text streams and binary streams. Because of the record-based nature of VSAM, this topic is organized differently from the other topics in this section. The focus of this topic is on record I/O, and only those aspects of text and binary I/O that are specific to VSAM are also discussed.
See z/OS XL C Support for the double-byte character set for information about
using wide-character I/O with z/OS XL C/C++.
Notes:
- This topic describes C I/O as it can be used within C++ programs.
- The C++ I/O stream libraries cannot be used for VSAM I/O because these do not support the record processing mode (where type=record is specified).
- Starting in z/OS V1R10, the C/C++ runtime library provides support for VSAM data sets in the extended addressing space on extended address volumes (EAVs).