This document specifies requirements for implementations of oneAPI Threading Building Blocks (oneTBB).

oneAPI Threading Building Blocks is a programming model for scalable parallel programming using standard ISO C++ code. A program uses oneTBB to specify logical parallelism in its algorithms, while a oneTBB implementation maps that parallelism onto execution threads.

oneTBB employs generic programming via C++ templates, with most of its interfaces defined by requirements on types and not specific types. Generic programming makes oneTBB flexible yet efficient, through customizing APIs to specific needs of an application.

C++11 is the minimal version of the C++ standard required by oneTBB. An implementation of oneTBB shall not require newer versions of the standard except where explicitly specified; also it shall not require any non-standard language extensions.

An implementation may use platform-specific APIs if those are compatible with the C++ execution and memory models. For example, a platform-specific implementation of threads may be used if that implementation provides the same execution guarantees as C++ threads.

An implementation of oneTBB shall support execution on single core and multi-core CPUs, including those that provide simultaneous multithreading capabilities.

On CPU, an implementation shall support nested parallelism, so that one can build larger parallel components from smaller parallel components.