What's new in Language Environment® for z/OS Version 1 Release 5

For z/OS Version 1 Release 5, Language Environment provides the following:

  • New and changed C/C++ functions
    • putenv() changes for the X/Open CAE Specification

      The putenv() function complies with the X/Open POSIX standard to place the input string directly into the environment array, rather than a copy. For migration considerations, see z/OS Language Environment Run-Time Migration Guide. This function was rolled back with APAR PQ61928.

    • Additional Enhanced ASCII support

      For additional functions supported, see z/OS C/C++ Run-Time Library Reference.

    • Multilevel security support

      Multilevel security allows the classification of data and users based on a system of hierarchical security levels, combined with a system of non-hierarchical security categories. The security administrator classifies users and data, and the system then imposes mandatory access controls restricting which users can access data, based on a comparison of the classification of the users and the data.

      Language Environment provides support for multilevel security through the following:

      • A port of entry function, __poe(), used to determine various levels of permission checking
      • A __writedown() function, used to query or change the setting of the write-down privilege
      • Support for setting the new SECLABEL field in the __chattr() and __fchattr() functions and in related headers
      • An __lchattr() function to assign security labels to symbolic links
      • Changes to the __getipc() function and related header to suport the IPCS display of _map resources

      See z/OS C/C++ Run-Time Library Reference for specific function descriptions.

    • Additional IEEE math functions

      For descriptions of the new and changed math functions, see z/OS C/C++ Run-Time Library Reference.

    • utoa() family of functions

      The itoa(), ltoa(), utoa() functions, and the unsigned versions utoa(), ultoa(), and ulltoa(), are provided for porting UNIX applications.

      For descriptions of these functions, see z/OS C/C++ Run-Time Library Reference.

    • C Transactional VSAM

      For DFSMS 1.5, Transactional VSAM extends VSAM record level sharing by adding commit and logging support for batch. This allows for full concurrent sharing of batch and CICS online applications that use either recoverable or non-recoverable datasets.

  • Java Support
    • Status stop

      Language Environment supports the use of the UNIX System Services STATUS STOP command, as part of the pthread_quiesce_and_get_np() function.

    • Support of Java stack overflow error

      Support is added in Language Environment for the Java stack overflow error. This supports the detection, reporting, and handling of overflow by the Java-specified soft stack limit. Support is provided in 31-bit XPLINK only. Using the new _set_stack_softlimit() and _far_jump() functions, you can set a soft stack limit and effectively perform a longjump() without a setjump(), thereby catching recursive storage leaks and avoiding setjump() overhead.

      Details on these two new functions are provided in z/OS Language Environment Vendor Interfaces.

  • Reliability, availability, serviceability
    • Heap pools serviceability

      Language Environment provides service support using tools and tracing capability to diagnose enabled heap pools.

  • Performance
    • Heap pools cell size maximum increase

      The cell size maximum and the number of pools managed by the HEAPPOOLS run-time option are increased. This enhancement extends HEAPPOOLS support by allowing a greater number of buffer pools and by increasing the size of the storage blocks within the pools.

      This improves the performance of multi-threaded applications with storage requests greater than 2KB and that use the HEAPPOOLS run-time option. The limit is increased to 64KB.

    • XPLINK high-performance Language Environment functions

      Provides high-performance support for the following functions in an XPLINK environment:

      • free() (non-heappools)
      • malloc() (non-heappools)
      • pthread_mutex_lock()
      • pthread_mutex_unlock()
      • pthread_rwlock_rdlock()
      • pthread_rwlock_wrlock()
      • pthread_rwlock_unlock()
      • __ufree()
      • __umalloc()
  • Debugging
    • Support for debugger application programming interface (API)

      A new API has been added to set and reset hooks. There is also a new environment variable to specifiy the name of the debug event handler that can be loaded from the hierarchical file system (HFS).

  • National Language Support (NLS)
    • Support for code pages IBM-4933 and IBM-13124

      Support has been added to allow conversions with code pages IBM-4933 and IBM-13124.

    • Additional G11N White Paper Currency Support

      This support provides additional country support by locales. For more information, see z/OS C/C++ Programming Guide.

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