The OMNI Thread Abstraction

The OMNI thread abstraction is designed to provide a common set of thread operations for use in programs written in C++. Programs written using the abstraction should be much easier to port between different architectures with different underlying threads primitives. The programming interface is designed to be similar to the C language interface to POSIX threads (IEEE draft standard 1003.1c — previously 1003.4a, often known as “pthreads” [POSIX94]). Much of the abstraction consists of simple C++ object wrappers around pthread calls. However for some features such as thread-specific data, a better interface can be offered because of the use of C++. Some of the more complex features of pthreads are not supported because of the difficulty of ensuring the same features can be offered on top of other thread systems. Such features include thread cancellation and complex scheduling control (though simple thread priorities are supported). The abstraction layer is currently implemented for the following architectures / thread systems: