Method and system for accessing virtual base classes
US5854931A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1997 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Jan 22, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/449
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for a computer compiler for an object-oriented programming language for implementing virtual functions and virtual base classes is provided. In preferred embodiments of the present invention, the data structure layout of an object includes a virtual function table pointer, a virtual base table pointer, occurrences of each non-virtual base class, the data members of the class, and occurrences of each virtual base class. If a class introduces a virtual function member and the class has a non-virtual base class with a virtual function table pointer, then the class shares the virtual function table pointer of the non-virtual base class that is first visited in a depth-first, left-to-right traversal of the inheritance tree. In preferred embodiments of the present invention, each instance of a given class shares a set of virtual function tables and virtual base tables for that class. In preferred embodiments, adjusters are used when a function member in a derived class overrides a function member that is defined in more than one base class, and when a derived class has a base class that overrides a function member in a virtual base class of that class and the derived class itsel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.