 The following libraries and utilities are delivered to support existing programs: - Common Debug Architecture (CDA) Libraries
- CDA is introduced with z/OS V1R5 to provide a consistent format for debug information on z/OS. The CDA Libraries provide a set of APIs to access this information.
- c89 Utility
- This utility compiles, assembles, and binds z/OS UNIX System Services C/C++ and assembler applications.
- UNIX System Laboratories (USL) I/O Stream Library
- The USL I/O Stream Library provides the standard input and output capabilities for C++.
- USL Complex Mathematics Library
- The Complex Mathematics Library provides the facilities to manipulate complex numbers and to perform standard mathematical operations on them.
- IBM Open Class DLLs
- The IBM Open Class run-time libraries are delivered with V1R5 to support existing programs. Application development using the IBM Open Class libraries have been withdrawn from service effective with z/OS V1R5, specifically, the Application Support Class Library and Collection Class library static objects, headers, source, samples and sidedecks are removed in z/OS V1R5.
We recommend that you migrate to the Standard C++ libraries. For more information about migrating away from the IOC libraries, see IBM Open Class Transition Guide.
NOTE: The UNIX System Laboratories (USL) I/O Stream Library and Complex Mathematics Library are still supported on z/OS, AIX, and OS/400. Although support for these classes is not being removed at this time, it is recommended that you migrate to the Standard C++ iostream and complex classes. This is especially important if you are migrating other IOC streaming classes to Standard C++ Library streaming classes, because combining USL and Standard C++ Library streams in one application is not recommended. For more information about the Standard C++ I/O Stream Library, see Standard C++ Library Reference. | 
