..
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.. meta::
  :description: Learn about libhipcxx conformance with the C++ Standard and its API and ABI versioning scheme, including the version macros from <cuda/std/version>.
  :keywords: libhipcxx, ROCm, HIP, conformance, ABI, versioning, C++ standard, ABI stability, ISO

.. _libhipcxx-conformance:

********************************************************************
Conformance and versioning
********************************************************************

Conformance
===========

libhipcxx aims to be a conforming implementation of the C++ Standard,
`ISO/IEC IS 14882 <https://eel.is/c++draft>`_, Clause 16 through 32.

Versioning
==========

libhipcxx is a fork of libcu++ and follows its versioning. A libhipcxx release carries the version of the upstream
`CCCL <https://github.com/NVIDIA/cccl>`_ release it is based on; the current version is 3.0.2.

API version
-----------

The API version is a three-component semantic version, ``MAJOR.MINOR.PATCH``, exposed by four macros from
``<cuda/std/version>``:

- ``_LIBCUDACXX_CUDA_API_VERSION_MAJOR`` is incremented for API-breaking changes.
- ``_LIBCUDACXX_CUDA_API_VERSION_MINOR`` is incremented when API-compatible features are added.
- ``_LIBCUDACXX_CUDA_API_VERSION_PATCH`` is incremented for all other changes.
- ``_LIBCUDACXX_CUDA_API_VERSION`` combines the three as ``MAJOR * 1000000 + MINOR * 1000 + PATCH``, which is
  ``3000002`` for version 3.0.2.

A single API version is supported at a time.

ABI version
-----------

The ABI version is a single integer. libhipcxx supports exactly one ABI version, 4, so both
``_LIBCUDACXX_CUDA_ABI_VERSION`` and ``_LIBCUDACXX_CUDA_ABI_VERSION_LATEST`` from ``<cuda/std/version>`` are 4.
Defining ``_LIBCUDACXX_CUDA_ABI_VERSION`` to any other value is a compile-time error.

libhipcxx makes no promise of long-term ABI stability. Promising long-term ABI stability would prevent fixing
mistakes and achieving high performance, so no such promises are made. A program is ill-formed, no diagnostic
required, if it links translation units that were compiled against different libhipcxx versions.