Reclaiming storage in an object oriented platform supporting extended C++ and Objective-C applications

This paper describes the experience obtained from the conception and implementation of a system for garbage collection in the INESC Comandos platform. The garbage collector is presently being used not only by applications written in C++ but also in Objective-C (both with some minor restrictions) since both languages are supported by the platform. In order to reclaim the memory used by objects, two algorithms were implemented: stop and copy with multiple generations and an incremental mark and sweep. The generational copying algorithm reduces drastically the time used to reclaim old objects when compared with a non-generational version. Besides these two algorithms, another one was developed in order to reclaim non-object memory (usually strings). This memory can be explicitly created by the programmer or by the communication subsystem in order to support distributed invocations