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# Release Notes <!-- omit in toc -->
This document contains changes of oneTBB compared to the last release.

## Table of Contents <!-- omit in toc -->
- [Known Limitations](#known-limitations)
- [Fixed Issues](#fixed-issues)
- [Open-source Contributions Integrated](#open-source-contributions-integrated)

## :rotating_light: Known Limitations
- A static assert causes compilation failures in oneTBB headers when compiling with Clang* 12.0.0 or newer if using the LLVM* standard library with -ffreestanding and C++11/14 compiler options.
- An application using Parallel STL algorithms in libstdc++ versions 9 and 10 may fail to compile due to incompatible interface changes between earlier versions of Threading Building Blocks (TBB) and oneAPI Threading Building Blocks (oneTBB). Disable support for Parallel STL algorithms by defining PSTL_USE_PARALLEL_POLICIES (in libstdc++ 9) or _GLIBCXX_USE_TBB_PAR_BACKEND (in libstdc++ 10) macro to zero before inclusion of the first standard header file in each translation unit.
- On Linux* OS, if oneAPI Threading Building Blocks (oneTBB) or Threading Building Blocks (TBB) are installed in a system folder like /usr/lib64, the application may fail to link due to the order in which the linker searches for libraries. Use the -L linker option to specify the correct location of oneTBB library. This issue does not affect the program execution.
- The oneapi::tbb::info namespace interfaces might unexpectedly change the process affinity mask on Windows* OS systems (see https://github.com/open-mpi/hwloc/issues/366 for details) when using hwloc version lower than 2.5.
- Using a hwloc version other than 1.11, 2.0, or 2.5 may cause an undefined behavior on Windows* OS. See https://github.com/open-mpi/hwloc/issues/477 for details.
- The NUMA topology may be detected incorrectly on Windows OS machines where the number of NUMA node threads exceeds the size of 1 processor group.
- On Windows OS on ARM64*, when compiling an application using oneTBB with the Microsoft* Compiler, the compiler issues a warning C4324 that a structure was padded due to the alignment specifier. Consider suppressing the warning by specifying /wd4324 to the compiler command line.
- oneTBB does not support fork(), to work-around the issue, consider using task_scheduler_handle to join oneTBB worker threads before using fork().
- C++ exception handling mechanism on Windows* OS on ARM64* might corrupt memory if an exception is thrown from any oneTBB parallel algorithm (see Windows* OS on ARM64* compiler issue: https://developercommunity.visualstudio.com/t/ARM64-incorrect-stack-unwinding-for-alig/1544293).

## :hammer: Fixed Issues
- Fixed oneapi::tbb::concurrent_bounded_queue::pop return type (GitHub* [#807](https://github.com/oneapi-src/oneTBB/issues/807)).
- Fixed oneapi::tbb::concurrent_queue and oneapi::tbb::concurrent_bounded_queue with non-default constructible value types (GitHub* [#885](https://github.com/oneapi-src/oneTBB/issues/885)).
- Fixed incorrect splitting of iteration space in case there is no support for proportional splitting in custom ranges.

## :octocat: Open-source Contributions Integrated
- Fix for full LTO* build, library and tests, on UNIX* OS systems. Contributed by Vladislav Shchapov (https://github.com/oneapi-src/oneTBB/pull/798).