> ## Documentation Index
> Fetch the complete documentation index at: https://bazel-pr-30012.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# C++ and Bazel

This page contains resources that help you use Bazel with C++ projects. It links
to a tutorial, build rules, and other information specific to building C++
projects with Bazel.

<h2 id="working-with-bazel">
  Working with Bazel
</h2>

The following resources will help you work with Bazel on C++ projects:

* [Tutorial: Building a C++ project](/versions/8.4.2/start/cpp)
* [C++ common use cases](/versions/8.4.2/tutorials/cpp-use-cases)
* [C/C++ rules](/versions/8.4.2/reference/be/c-cpp)
* Essential Libraries
  * [Abseil](https://abseil.io/docs/cpp/quickstart)
  * [Boost](https://github.com/nelhage/rules_boost)
  * [HTTPS Requests: CPR and libcurl](https://github.com/hedronvision/bazel-make-cc-https-easy)
* [C++ toolchain configuration](/versions/8.4.2/docs/cc-toolchain-config-reference)
* [Tutorial: Configuring C++ toolchains](/versions/8.4.2/tutorials/ccp-toolchain-config)
* [Integrating with C++ rules](/versions/8.4.2/configure/integrate-cpp)

<h2 id="best-practices">
  Best practices
</h2>

In addition to [general Bazel best practices](/versions/8.4.2/configure/best-practices), below are
best practices specific to C++ projects.

<h3 id="build-files">
  BUILD files
</h3>

Follow the guidelines below when creating your BUILD files:

* Each `BUILD` file should contain one [`cc_library`](/versions/8.4.2/reference/be/c-cpp#cc_library)
  rule target per compilation unit in the directory.

* You should granularize your C++ libraries as much as
  possible to maximize incrementality and parallelize the build.

* If there is a single source file in `srcs`, name the library the same as
  that C++ file's name. This library should contain C++ file(s), any matching
  header file(s), and the library's direct dependencies. For example:

  ```python theme={null}
  cc_library(
      name = "mylib",
      srcs = ["mylib.cc"],
      hdrs = ["mylib.h"],
      deps = [":lower-level-lib"]
  )
  ```

* Use one `cc_test` rule target per `cc_library` target in the file. Name the
  target `[library-name]_test` and the source file `[library-name]_test.cc`.
  For example, a test target for the `mylib` library target shown above would
  look like this:

  ```python theme={null}
  cc_test(
      name = "mylib_test",
      srcs = ["mylib_test.cc"],
      deps = [":mylib"]
  )
  ```

<h3 id="include-paths">
  Include paths
</h3>

Follow these guidelines for include paths:

* Make all include paths relative to the workspace directory.

* Use quoted includes (`#include "foo/bar/baz.h"`) for non-system headers, not
  angle-brackets (`#include <foo/bar/baz.h>`).

* Avoid using UNIX directory shortcuts, such as `.` (current directory) or `..`
  (parent directory).

* For legacy or `third_party` code that requires includes pointing outside the
  project repository, such as external repository includes requiring a prefix,
  use the [`include_prefix`](/versions/8.4.2/reference/be/c-cpp#cc_library.include_prefix) and
  [`strip_include_prefix`](/versions/8.4.2/reference/be/c-cpp#cc_library.strip_include_prefix)
  arguments on the `cc_library` rule target.

<h3 id="toolchain-features">
  Toolchain features
</h3>

The following optional [features](/versions/8.4.2/docs/cc-toolchain-config-reference#features)
can improve the hygiene of a C++ project. They can be enabled using the
`--features` command-line flag or the `features` attribute of
[`repo`](/versions/8.4.2/external/overview#repo.bazel),
[`package`](/versions/8.4.2/reference/be/functions#package) or `cc_*` rules:

* The `parse_headers` feature makes it so that the C++ compiler is used to parse
  (but not compile) all header files in the built targets and their dependencies
  when using the
  [`--process_headers_in_dependencies`](/versions/8.4.2/reference/command-line-reference#flag--process_headers_in_dependencies)
  flag. This can help catch issues in header-only libraries and ensure that
  headers are self-contained and independent of the order in which they are
  included.
* The `layering_check` feature enforces that targets only include headers
  provided by their direct dependencies. The default toolchain supports this
  feature on Linux with `clang` as the compiler.