.. _module-pw_third_party_llvm_libcxx:

===========
LLVM libcxx
===========
The ``$dir_pw_third_party/llvm_libcxx/`` module provides various helpers to
optionally use LLVM libcxx with :ref:`module-pw_libcxx`.

---------------------------
Using upstream LLVM libcxx
---------------------------
If you want to use LLVM libcxx, you must do the following:

Submodule
=========
Add LLVM libcxx to your workspace with the following command.

.. code-block:: sh

   git submodule add https://llvm.googlesource.com/llvm-project/libcxx \
     third_party/llvm_libcxx/src

Note, this git repository is maintained by Google and is a slice of upstream
LLVM including only the libcxx subdirectory.

GN
==
* Set the GN var ``dir_pw_third_party_llvm_libcxx`` to the location of the LLVM
  libcxx source. If you used the command above, this will be
  ``//third_party/llvm_libcxx/src``

  This can be set in your args.gn or .gn file like:
  ``dir_pw_third_party_llvm_libcxx = "//third_party/llvm_libcxx_src"``

------
Status
------
pw_libcxx's llvm_libcxx integration is under active development.