Introduction to HP aC++

HP aC++ is Hewlett-Packard's implementation of the ANSI/ISO C++ International Standard. The compiler largely conforms to the standard and is evolving towards full conformance. Refer to Standardizing Your Code for listings of standards based features and extensions. Some of the many supported features are listed here:

New Features in this HP aC++ A.01.21 Release

Header File Caching is an additional, simplified method of precompiling header files.
A new debugging option, +[no]objdebug, enables faster links and smaller executable file sizes for large applications.

Additional Options for Standardizing Your Code:
- -Wc,-ansi_for_scope,[on] enables standard scoping rules for init-declarations in for statements.
- -Aa sets all C++ standard options on (currently Koenig lookup and for scoping rules).

Additional Options for Code Optimization:
- +Olevel=name1[,name2,...,nameN]
- +Oreusedir=DirectoryPath
A new template option, +inst_directed, to suppress assigner output in object files. Use it instead of the +inst_none option with code that contains explicit instantiations only and does not require automatic (assigner) instantiation.

The #pragma pack directive allows you to specify the maximum alignment of class fields having non-class types. This pragma may be useful when importing code from other architectures where data type alignment may be different from default PA-RISC alignment.

Three new pragmas for improving the performance of shared libraries.

By eliminating references to the standard header files and libraries bundled with HP aC++, the +nostl option allows experienced users full control over the header files and libraries used in the compilation and linking of their applications.

See additional information about HP aC++ diagnostic messages.

To see which include files led to an error or warning, specify the -Wc,-diagnose_includes,on option.

Floating installation allows more than one version of HP aC++ to be installed on one system at the same time.

The__HP_aCC predefined macro now contains the HP aC++ driver version number. For example, for version A.01.21, __HP_aCC = 012100
The __HP_aCC predefined macro was introduced in HP aC++ version A.01.15. It's value was 1 for HP aC++ A.01.15 and A.01.18.

In prior releases, the standard C++ library (libstd) and RogueWave's tools.h++ library (librwtool) were not thread safe in all cases. The -D__HPACC_THREAD_SAFE_RB_TREE preprocessor macro insures thread safety.

Release Notes

For the latest information on new features, see the HP aC++ Release Notes

If you see the message "Text file data could not be formatted," ensure the release notes are installed as /opt/aCC/newconfig/RelNotes/ACXX.release.notes.

Migration

If you are migrating code from HP C++ (cfront) to HP aC++, click here to find out where to obtain information.

Features Introduced in Prior Releases

New Default Template Instantiation Mechanism
Support for Member Templates as Defined in the ANSI/ISO C++ International Standard

New Default Template Instatiation Mechanism

The HP aC++ default template instantiation mechanism has changed to compile-time instantiation (CTTI). For source code containing templates, the new default may result in faster compile-time processing.

The previous default behavior remains available by specifying the +inst_auto command-line option when compiling and linking. If you provide archive or shared libraries for distribution, you may want to use +inst_auto to insure consistent behavior between each distribution of your libraries.

Also, if you provide either archive or shared library products, and your customers need to use the prior template instantiation default in their builds, you must build your libraries by using the +inst_auto option.

For More Information

Refer to Using HP aC++ Templates in this online programmer's guide and to the online technical document, Using Templates in HP aC++ for details about template instantiation and migration.