C++ is a general-purpose programming language designed at AT&T
Bell Laboratories and licensed through USL.
Based on the C programming language, C++ was designed
to be used in a C programming environment on a UNIX system. C++ retains
most of C's efficiency and flexibility, incorporates all the features
of C, and also supports features that are unavailable in the C language.
Many of the added features were designed to support object-oriented
programming.
Dr. Bjarne Stroustrup, author of The C++ Programming Language,
designed most of the new language, with additional contributions
from Brian Kernighan and other Bell Labs staff. In undertaking the
project, Stroustrup borrowed successful features from other older
languages. As a result, C++ incorporates the concepts of classes
and virtual functions from Simula67. C++ borrows the idea of operator overloading from Algol 68. These features are an important part of the
support that C++ provides for object-oriented programming.
Early versions of the language were collectively known as "C with
Classes" and lacked many details that were added later. According
to Stroustrup, the name C++ was coined by Rick Mascitti. The name
is a play on words since "++" is the C increment operator and
can also be taken to signify the evolution of changes from C. Stroustrup
also points out that the language is not called D because it does
not remove any features of C, but rather it is an extension of C.
The USL translator has evolved through several releases. Version
1.0, the original release, reflects the language as defined in Bjarne
Stroustrup's The C++ Programming Language. Version 1.1 added
two features: pointers to member functions and the keyword protected.
Version 1.2 added support for the overloading of unsigned integers
and unsigned longs.
Version 2.0 added several major features, including
support for multiple inheritance, additional operator overloading,
and type-safe linkage. Version 2.0 also fixed a number of problems
in the C++ language. As a result, version 2.0 is not backward compatible
with previous releases.
Version 2.1 primarily repaired defects and more rigorously enforced the
definition of the language. In addition, HP C++ added compiler mode to
version 2.1, which compiles C++ source directly to object code instead of translating it to C. This reduces compilation time significantly. Version 2.1 is both source compatible and link compatible with version 2.0.
The C++ Programming Language, written by Bjarne Stroustrup, contains
the definition of the C++ language supported by the current version,
3.0. (Language features that are not implemented in version 3.0 are
listed in appendix C, "Not Implemented Messages," of the C++ Language System Release Notes.)
Version 3.0 adds significant new functionality in templates, true nested
classes, protected derivation, and a number of other new features.
HP C++ implements version
3.0 of the USL translator and adds an exception handling mechanism
that conforms to the definition in The C++ Programming Language.
HP C++ also supports shared libraries on HP-UX by allowing you to
create position-independent code (PIC).
