1.. _limitations: 2 3Known Limitations 4***************** 5 6This page outlines the known limitations of oneTBB to help you better understand its capabilities. 7 8Freestanding Compilation Mode 9^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 10 11**Limitation:** oneTBB does not support the freestanding compilation mode. 12 13**Risk:** Compiling an application that utilizes oneTBB headers using the Intel(R) oneAPI DPC+/C+ Compiler may result in failure on Windows* OS if the ``/Qfreestanding`` compiler option is employed. 14 15Static Assert 16^^^^^^^^^^^^^ 17 18**Limitation:** A static assert causes the compilation failures in oneTBB headers if the following conditions are satisfied: 19 20 * Compilation is done with Clang 12.0.0 or a more recent version. 21 * The LLVM standard library is employed, coupled with the use of the ``-ffreestanding`` flag and C++11/14 compiler options. 22 23**Risk:** The compilation failures. 24 25Interface Incompatibilities: TBB vs oneTBB 26^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 27 28**Limitation:** An application using Parallel STL algorithms in the ``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). 29 30**Solution:** 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. 31 32Incorrect Installation Location 33^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 34 35**Limitation:** On Linux* OS, if oneAPI Threading Building Blocks (oneTBB) or Threading Building Blocks (TBB) are installed in a system folder, such as ``/usr/lib64``, the application may fail to link due to the order in which the linker searches for libraries. 36 37**Risk:** The issue does not affect the program execution. 38 39**Solution:** Use the ``-L`` linker option to specify the correct location of oneTBB library. 40 41``fork()`` Support 42^^^^^^^^^^^^^^^^^^^ 43 44**Limitation:** oneTBB does not support ``fork()``. 45 46**Solution:** To work-around the issue, consider using ``task_scheduler_handle`` to join oneTBB worker threads before using ``fork()``. 47