.. Licensed to the Apache Software Foundation (ASF) under one .. or more contributor license agreements. See the NOTICE file .. distributed with this work for additional information .. regarding copyright ownership. The ASF licenses this file .. to you under the Apache License, Version 2.0 (the .. "License"); you may not use this file except in compliance .. with the License. You may obtain a copy of the License at .. http://www.apache.org/licenses/LICENSE-2.0 .. Unless required by applicable law or agreed to in writing, .. software distributed under the License is distributed on an .. "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY .. KIND, either express or implied. See the License for the .. specific language governing permissions and limitations .. under the License. .. highlight:: console .. _building-arrow-cpp: ================== Building Arrow C++ ================== System setup ============ Arrow uses CMake as a build configuration system. We recommend building out-of-source. If you are not familiar with this terminology: * **In-source build**: ``cmake`` is invoked directly from the ``cpp`` directory. This can be inflexible when you wish to maintain multiple build environments (e.g. one for debug builds and another for release builds) * **Out-of-source build**: ``cmake`` is invoked from another directory, creating an isolated build environment that does not interact with any other build environment. For example, you could create ``cpp/build-debug`` and invoke ``cmake $CMAKE_ARGS ..`` from this directory Building requires: * A C++20-enabled compiler. On Linux, gcc 12 and higher should be sufficient. * CMake 3.25 or higher * On Linux and macOS, either ``make`` or ``ninja`` build utilities * At least 1GB of RAM for a minimal build, 4GB for a minimal debug build with tests and 8GB for a full build using :ref:`docker `. On Ubuntu/Debian you can install the requirements with: .. code-block:: shell sudo apt-get install \ build-essential \ ninja-build \ cmake On Alpine Linux: .. code-block:: shell apk add autoconf \ bash \ cmake \ g++ \ gcc \ ninja \ make On Fedora Linux: .. code-block:: shell sudo dnf install \ cmake \ gcc \ gcc-c++ \ ninja-build \ make On Arch Linux: .. code-block:: shell sudo pacman -S --needed \ base-devel \ ninja \ cmake On macOS, you can use `Homebrew `_: .. code-block:: shell git clone https://github.com/apache/arrow.git cd arrow brew update && brew bundle --file=cpp/Brewfile With `vcpkg `_: .. code-block:: shell git clone https://github.com/apache/arrow.git cd arrow vcpkg install \ --x-manifest-root cpp \ --feature-flags=versions \ --clean-after-build On MSYS2: .. code-block:: shell pacman --sync --refresh --noconfirm \ ccache \ git \ mingw-w64-${MSYSTEM_CARCH}-boost \ mingw-w64-${MSYSTEM_CARCH}-brotli \ mingw-w64-${MSYSTEM_CARCH}-cmake \ mingw-w64-${MSYSTEM_CARCH}-gcc \ mingw-w64-${MSYSTEM_CARCH}-gflags \ mingw-w64-${MSYSTEM_CARCH}-glog \ mingw-w64-${MSYSTEM_CARCH}-gtest \ mingw-w64-${MSYSTEM_CARCH}-lz4 \ mingw-w64-${MSYSTEM_CARCH}-protobuf \ mingw-w64-${MSYSTEM_CARCH}-python3-numpy \ mingw-w64-${MSYSTEM_CARCH}-rapidjson \ mingw-w64-${MSYSTEM_CARCH}-snappy \ mingw-w64-${MSYSTEM_CARCH}-thrift \ mingw-w64-${MSYSTEM_CARCH}-zlib \ mingw-w64-${MSYSTEM_CARCH}-zstd .. _cpp-building-building: Building ======== All the instructions below assume that you have cloned the Arrow git repository and navigated to the ``cpp`` subdirectory: .. code-block:: $ git clone https://github.com/apache/arrow.git $ cd arrow/cpp .. _cmake_presets: CMake presets ------------- Using CMake version 3.21.0 or higher, some presets for various build configurations are provided. You can get a list of the available presets using ``cmake --list-presets``: .. code-block:: $ cmake --list-presets # from inside the `cpp` subdirectory Available configure presets: "ninja-debug-minimal" - Debug build without anything enabled "ninja-debug-basic" - Debug build with tests and reduced dependencies "ninja-debug" - Debug build with tests and more optional components [ etc. ] You can inspect the specific options enabled by a given preset using ``cmake -N --preset ``: .. code-block:: $ cmake --preset -N ninja-debug-minimal Preset CMake variables: ARROW_BUILD_INTEGRATION="OFF" ARROW_BUILD_STATIC="OFF" ARROW_BUILD_TESTS="OFF" ARROW_EXTRA_ERROR_CONTEXT="ON" ARROW_WITH_RE2="OFF" ARROW_WITH_UTF8PROC="OFF" CMAKE_BUILD_TYPE="Debug" You can also create a build from a given preset: .. code-block:: $ mkdir build # from inside the `cpp` subdirectory $ cd build $ cmake .. --preset ninja-debug-minimal Preset CMake variables: ARROW_BUILD_INTEGRATION="OFF" ARROW_BUILD_STATIC="OFF" ARROW_BUILD_TESTS="OFF" ARROW_EXTRA_ERROR_CONTEXT="ON" ARROW_WITH_RE2="OFF" ARROW_WITH_UTF8PROC="OFF" CMAKE_BUILD_TYPE="Debug" -- Building using CMake version: 3.21.3 [ etc. ] and then ask to compile the build targets: .. code-block:: $ cmake --build . [142/142] Creating library symlink debug/libarrow.so.700 debug/libarrow.so $ tree debug/ debug/ ├── libarrow.so -> libarrow.so.700 ├── libarrow.so.700 -> libarrow.so.700.0.0 └── libarrow.so.700.0.0 0 directories, 3 files $ cmake --install . When creating a build, it is possible to pass custom options besides the preset-defined ones, for example: .. code-block:: $ cmake .. --preset ninja-debug-minimal -DCMAKE_INSTALL_PREFIX=/usr/local .. note:: The CMake presets are provided as a help to get started with Arrow development and understand common build configurations. They are not guaranteed to be immutable but may change in the future based on feedback. Instead of relying on CMake presets, it is **highly recommended** that automated builds, continuous integration, release scripts, etc. use manual configuration, as outlined below. .. seealso:: `Official documentation for CMake presets `_. Manual configuration -------------------- The build system uses ``CMAKE_BUILD_TYPE=release`` by default, so if this argument is omitted then a release build will be produced. .. note:: You need to set more options to build on Windows. See :ref:`developers-cpp-windows` for details. Several build types are possible: * ``Debug``: doesn't apply any compiler optimizations and adds debugging information in the binary. * ``RelWithDebInfo``: applies compiler optimizations while adding debug information in the binary. * ``Release``: applies compiler optimizations and removes debug information from the binary. .. note:: These build types provide suitable optimization/debug flags by default but you can change them by specifying ``-DARROW_C_FLAGS_${BUILD_TYPE}=...`` and/or ``-DARROW_CXX_FLAGS_${BUILD_TYPE}=...``. ``${BUILD_TYPE}`` is upper case of build type. For example, ``DEBUG`` (``-DARROW_C_FLAGS_DEBUG=...`` / ``-DARROW_CXX_FLAGS_DEBUG=...``) for the ``Debug`` build type and ``RELWITHDEBINFO`` (``-DARROW_C_FLAGS_RELWITHDEBINFO=...`` / ``-DARROW_CXX_FLAGS_RELWITHDEBINFO=...``) for the ``RelWithDebInfo`` build type. For example, you can use ``-O3`` as an optimization flag for the ``Release`` build type by passing ``-DARROW_CXX_FLAGS_RELEASE=-O3`` . You can use ``-g3`` as a debug flag for the ``Debug`` build type by passing ``-DARROW_CXX_FLAGS_DEBUG=-g3`` . You can also use the standard ``CMAKE_C_FLAGS_${BUILD_TYPE}`` and ``CMAKE_CXX_FLAGS_${BUILD_TYPE}`` variables but the ``ARROW_C_FLAGS_${BUILD_TYPE}`` and ``ARROW_CXX_FLAGS_${BUILD_TYPE}`` variables are recommended. The ``CMAKE_C_FLAGS_${BUILD_TYPE}`` and ``CMAKE_CXX_FLAGS_${BUILD_TYPE}`` variables replace all default flags provided by CMake, while ``ARROW_C_FLAGS_${BUILD_TYPE}`` and ``ARROW_CXX_FLAGS_${BUILD_TYPE}`` just append the flags specified, which allows selectively overriding some of the defaults. You can also run default build with flag ``-DARROW_EXTRA_ERROR_CONTEXT=ON``, see :ref:`cpp-extra-debugging`. Minimal release build (1GB of RAM for building or more recommended): .. code-block:: $ mkdir build-release $ cd build-release $ cmake .. $ make -j8 # if you have 8 CPU cores, otherwise adjust $ make install Minimal debug build with unit tests (4GB of RAM for building or more recommended): .. code-block:: $ git submodule update --init --recursive $ export ARROW_TEST_DATA=$PWD/../testing/data $ mkdir build-debug $ cd build-debug $ cmake -DCMAKE_BUILD_TYPE=Debug -DARROW_BUILD_TESTS=ON .. $ make -j8 # if you have 8 CPU cores, otherwise adjust $ make unittest # to run the tests $ make install The unit tests are not built by default. After building, one can also invoke the unit tests using the ``ctest`` tool provided by CMake (note that ``test`` depends on ``python`` being available). On some Linux distributions, running the test suite might require setting an explicit locale. If you see any locale-related errors, try setting the environment variable (which requires the ``locales`` package or equivalent): .. code-block:: $ export LC_ALL="en_US.UTF-8" Faster builds with Ninja ~~~~~~~~~~~~~~~~~~~~~~~~ Many contributors use the `Ninja build system `_ to get faster builds. It especially speeds up incremental builds. To use ``ninja``, pass ``-GNinja`` when calling ``cmake`` and then use the ``ninja`` command instead of ``make``. Unity builds ~~~~~~~~~~~~ The CMake `unity builds `_ option can make full builds significantly faster, but it also increases the memory requirements. Consider turning it on (using ``-DCMAKE_UNITY_BUILD=ON``) if memory consumption is not an issue. .. _cpp_build_optional_components: Optional Components ~~~~~~~~~~~~~~~~~~~ By default, the C++ build system creates a fairly minimal build. We have several optional system components which you can opt into building by passing boolean flags to ``cmake``. * ``-DARROW_BUILD_UTILITIES=ON`` : Build Arrow commandline utilities * ``-DARROW_COMPUTE=ON``: Build all computational kernel functions * ``-DARROW_CSV=ON``: CSV reader module * ``-DARROW_CUDA=ON``: CUDA integration for GPU development. Depends on NVIDIA CUDA toolkit. The CUDA toolchain used to build the library can be customized by using the ``$CUDA_HOME`` environment variable. * ``-DARROW_DATASET=ON``: Dataset API, implies the Filesystem API * ``-DARROW_FILESYSTEM=ON``: Filesystem API for accessing local and remote filesystems * ``-DARROW_FLIGHT=ON``: Arrow Flight RPC system, which depends at least on gRPC * ``-DARROW_FLIGHT_SQL=ON``: Arrow Flight SQL * ``-DARROW_GANDIVA=ON``: Gandiva expression compiler, depends on LLVM, Protocol Buffers, and re2 * ``-DARROW_GANDIVA_JAVA=ON``: Gandiva JNI bindings for Java * ``-DARROW_GCS=ON``: Build Arrow with GCS support (requires the GCloud SDK for C++) * ``-DARROW_HDFS=ON``: Arrow integration with libhdfs for accessing the Hadoop Filesystem * ``-DARROW_JEMALLOC=ON``: Build the Arrow jemalloc-based allocator, on by default * ``-DARROW_JSON=ON``: JSON reader module * ``-DARROW_MIMALLOC=ON``: Build the Arrow mimalloc-based allocator * ``-DARROW_ORC=ON``: Arrow integration with Apache ORC * ``-DARROW_PARQUET=ON``: Apache Parquet libraries and Arrow integration * ``-DPARQUET_REQUIRE_ENCRYPTION=ON``: Parquet Modular Encryption * ``-DARROW_PYTHON=ON``: This option is deprecated since 10.0.0. This will be removed in a future release. Use CMake presets instead. Or you can enable ``ARROW_COMPUTE``, ``ARROW_CSV``, ``ARROW_DATASET``, ``ARROW_FILESYSTEM``, ``ARROW_HDFS``, and ``ARROW_JSON`` directly instead. * ``-DARROW_S3=ON``: Support for Amazon S3-compatible filesystems * ``-DARROW_SUBSTRAIT=ON``: Build with support for Substrait * ``-DARROW_WITH_RE2=ON``: Build with support for regular expressions using the re2 library, on by default and used when ``ARROW_COMPUTE`` or ``ARROW_GANDIVA`` is ``ON`` * ``-DARROW_WITH_UTF8PROC=ON``: Build with support for Unicode properties using the utf8proc library, on by default and used when ``ARROW_COMPUTE`` or ``ARROW_GANDIVA`` is ``ON`` * ``-DARROW_TENSORFLOW=ON``: Build Arrow with TensorFlow support enabled Compression options available in Arrow are: * ``-DARROW_WITH_BROTLI=ON``: Build support for Brotli compression * ``-DARROW_WITH_BZ2=ON``: Build support for BZ2 compression * ``-DARROW_WITH_LZ4=ON``: Build support for lz4 compression * ``-DARROW_WITH_SNAPPY=ON``: Build support for Snappy compression * ``-DARROW_WITH_ZLIB=ON``: Build support for zlib (gzip) compression * ``-DARROW_WITH_ZSTD=ON``: Build support for ZSTD compression Some features of the core Arrow shared library can be switched off for improved build times if they are not required for your application: * ``-DARROW_IPC=ON``: build the IPC extensions .. note:: If your use-case is limited to reading/writing Arrow data then the default options should be sufficient. However, if you wish to build any tests/benchmarks then ``ARROW_JSON`` is also required (it will be enabled automatically). If extended format support is desired then adding ``ARROW_PARQUET``, ``ARROW_CSV``, ``ARROW_JSON``, or ``ARROW_ORC`` shouldn't enable any additional components. .. note:: In general, it's a good idea to enable ``ARROW_COMPUTE`` if you anticipate using any compute kernels beyond ``cast``. While there are (as of 12.0.0) a handful of additional kernels built in by default, this list may change in the future as it's partly based on kernel usage in the current format implementations. Optional Targets ~~~~~~~~~~~~~~~~ For development builds, you will often want to enable additional targets in enable to exercise your changes, using the following ``cmake`` options. * ``-DARROW_BUILD_BENCHMARKS=ON``: Build executable benchmarks. * ``-DARROW_BUILD_EXAMPLES=ON``: Build examples of using the Arrow C++ API. * ``-DARROW_BUILD_INTEGRATION=ON``: Build additional executables that are used to exercise protocol interoperability between the different Arrow implementations. * ``-DARROW_BUILD_UTILITIES=ON``: Build executable utilities. * ``-DARROW_BUILD_TESTS=ON``: Build executable unit tests. * ``-DARROW_ENABLE_TIMING_TESTS=ON``: If building unit tests, enable those unit tests that rely on wall-clock timing (this flag is disabled on CI because it can make test results flaky). * ``-DARROW_FUZZING=ON``: Build fuzz targets and related executables. Optional Checks ~~~~~~~~~~~~~~~ The following special checks are available as well. They instrument the generated code in various ways so as to detect select classes of problems at runtime (for example when executing unit tests). * ``-DARROW_USE_ASAN=ON``: Enable Address Sanitizer to check for memory leaks, buffer overflows or other kinds of memory management issues. * ``-DARROW_USE_TSAN=ON``: Enable Thread Sanitizer to check for races in multi-threaded code. * ``-DARROW_USE_UBSAN=ON``: Enable Undefined Behavior Sanitizer to check for situations which trigger C++ undefined behavior. Some of those options are mutually incompatible, so you may have to build several times with different options if you want to exercise all of them. CMake version requirements ~~~~~~~~~~~~~~~~~~~~~~~~~~ We support CMake 3.25 and higher. LLVM and Clang Tools ~~~~~~~~~~~~~~~~~~~~ We are currently using LLVM for library builds and for other developer tools such as code formatting with ``clang-format``. LLVM can be installed via most modern package managers (apt, yum, conda, Homebrew, vcpkg, chocolatey). .. _cpp-build-dependency-management: Build Dependency Management =========================== The build system supports a number of third-party dependencies * ``AWSSDK``: for S3 support, requires system cURL and can use the ``BUNDLED`` method described below * ``benchmark``: Google benchmark, for testing * ``Boost``: for cross-platform support * ``Brotli``: for data compression * ``BZip2``: for data compression * ``c-ares``: a dependency of gRPC * ``gflags``: for command line utilities (formerly Googleflags) * ``GLOG``: for logging * ``google_cloud_cpp_storage``: for Google Cloud Storage support, requires system cURL and can use the ``BUNDLED`` method described below * ``gRPC``: for remote procedure calls * ``GTest``: Googletest, for testing * ``LLVM``: a dependency of Gandiva * ``Lz4``: for data compression * ``ORC``: for Apache ORC format support * ``re2``: for compute kernels and Gandiva, a dependency of gRPC * ``Protobuf``: Google Protocol Buffers, for data serialization * ``RapidJSON``: for data serialization * ``Snappy``: for data compression * ``Thrift``: Apache Thrift, for data serialization * ``utf8proc``: for compute kernels * ``ZLIB``: for data compression * ``zstd``: for data compression The CMake option ``ARROW_DEPENDENCY_SOURCE`` is a global option that instructs the build system how to resolve each dependency. There are a few options: * ``AUTO``: Try to find package in the system default locations and build from source if not found * ``BUNDLED``: Building the dependency automatically from source * ``SYSTEM``: Finding the dependency in system paths using CMake's built-in ``find_package`` function, or using ``pkg-config`` for packages that do not have this feature * ``CONDA``: Use ``$CONDA_PREFIX`` as alternative ``SYSTEM`` PATH * ``VCPKG``: Find dependencies installed by vcpkg, and if not found, run ``vcpkg install`` to install them * ``BREW``: Use Homebrew default paths as an alternative ``SYSTEM`` path The default method is ``AUTO`` unless you are developing within an active conda environment (detected by presence of the ``$CONDA_PREFIX`` environment variable), in which case it is ``CONDA``. Individual Dependency Resolution -------------------------------- While ``-DARROW_DEPENDENCY_SOURCE=$SOURCE`` sets a global default for all packages, the resolution strategy can be overridden for individual packages by setting ``-D$PACKAGE_NAME_SOURCE=..``. For example, to build Protocol Buffers from source, set .. code-block:: shell -DProtobuf_SOURCE=BUNDLED This variable is unfortunately case-sensitive; the name used for each package is listed above, but the most up-to-date listing can be found in `cpp/cmake_modules/ThirdpartyToolchain.cmake `_. Bundled Dependency Versions --------------------------- When using the ``BUNDLED`` method to build a dependency from source, the version number from ``cpp/thirdparty/versions.txt`` is used. There is also a dependency source downloader script (see below), which can be used to set up offline builds. When using ``BUNDLED`` for dependency resolution (and if you use either the jemalloc or mimalloc allocators, which are recommended), statically linking the Arrow libraries in a third party project is more complex. See below for instructions about how to configure your build system in this case. Boost-related Options --------------------- We depend on some Boost C++ libraries for cross-platform support. In most cases, the Boost version available in your package manager may be new enough, and the build system will find it automatically. If you have Boost installed in a non-standard location, you can specify it by passing ``-DBOOST_ROOT=$MY_BOOST_ROOT`` or setting the ``BOOST_ROOT`` environment variable. Offline Builds -------------- If you do not use the above variables to direct the Arrow build system to preinstalled dependencies, they will be built automatically by the Arrow build system. The source archive for each dependency will be downloaded via the internet, which can cause issues in environments with limited access to the internet. To enable offline builds, you can download the source artifacts yourself and use environment variables of the form ``ARROW_$LIBRARY_URL`` to direct the build system to read from a local file rather than accessing the internet. To make this easier for you, we have prepared a script ``thirdparty/download_dependencies.sh`` which will download the correct version of each dependency to a directory of your choosing. It will print a list of bash-style environment variable statements at the end to use for your build script. .. code-block:: # Download tarballs into $HOME/arrow-thirdparty $ ./thirdparty/download_dependencies.sh $HOME/arrow-thirdparty You can then invoke CMake to create the build directory and it will use the declared environment variable pointing to downloaded archives instead of downloading them (one for each build dir!). Statically Linking ------------------ When ``-DARROW_BUILD_STATIC=ON``, all build dependencies built as static libraries by the Arrow build system will be merged together to create a static library ``arrow_bundled_dependencies``. In UNIX-like environments (Linux, macOS, MinGW), this is called ``libarrow_bundled_dependencies.a`` and on Windows with Visual Studio ``arrow_bundled_dependencies.lib``. This "dependency bundle" library is installed in the same place as the other Arrow static libraries. If you are using CMake, the bundled dependencies will automatically be included when linking if you use the ``arrow_static`` CMake target. In other build systems, you may need to explicitly link to the dependency bundle. We created an `example CMake-based build configuration `_ to show you a working example. On Linux and macOS, if your application does not link to the ``pthread`` library already, you must include ``-pthread`` in your linker setup. In CMake this can be accomplished with the ``Threads`` built-in package: .. code-block:: cmake set(THREADS_PREFER_PTHREAD_FLAG ON) find_package(Threads REQUIRED) target_link_libraries(my_target PRIVATE Threads::Threads) .. _cpp-extra-debugging: Extra debugging help -------------------- If you use the CMake option ``-DARROW_EXTRA_ERROR_CONTEXT=ON`` it will compile the libraries with extra debugging information on error checks inside the ``RETURN_NOT_OK`` macro. In unit tests with ``ASSERT_OK``, this will yield error outputs like: .. code-block:: shell ../src/arrow/ipc/ipc-read-write-test.cc:609: Failure Failed ../src/arrow/ipc/metadata-internal.cc:508 code: TypeToFlatbuffer(fbb, *field.type(), &children, &layout, &type_enum, dictionary_memo, &type_offset) ../src/arrow/ipc/metadata-internal.cc:598 code: FieldToFlatbuffer(fbb, *schema.field(i), dictionary_memo, &offset) ../src/arrow/ipc/metadata-internal.cc:651 code: SchemaToFlatbuffer(fbb, schema, dictionary_memo, &fb_schema) ../src/arrow/ipc/writer.cc:697 code: WriteSchemaMessage(schema_, dictionary_memo_, &schema_fb) ../src/arrow/ipc/writer.cc:730 code: WriteSchema() ../src/arrow/ipc/writer.cc:755 code: schema_writer.Write(&dictionaries_) ../src/arrow/ipc/writer.cc:778 code: CheckStarted() ../src/arrow/ipc/ipc-read-write-test.cc:574 code: writer->WriteRecordBatch(batch) NotImplemented: Unable to convert type: decimal(19, 4) Deprecations and API Changes ---------------------------- We use the marco ``ARROW_DEPRECATED`` which wraps C++ deprecated attribute for APIs that have been deprecated. It is a good practice to compile third party applications with ``-Werror=deprecated-declarations`` (for GCC/Clang or similar flags of other compilers) to proactively catch and account for API changes. Modular Build Targets --------------------- Since there are several major parts of the C++ project, we have provided modular CMake targets for building each library component, group of unit tests and benchmarks, and their dependencies: * ``make arrow`` for Arrow core libraries * ``make parquet`` for Parquet libraries * ``make gandiva`` for Gandiva (LLVM expression compiler) libraries .. note:: If you have selected Ninja as CMake generator, replace ``make arrow`` with ``ninja arrow``, and so on. To build the unit tests or benchmarks, add ``-tests`` or ``-benchmarks`` to the target name. So ``make arrow-tests`` will build the Arrow core unit tests. Using the ``-all`` target, e.g. ``parquet-all``, will build everything. If you wish to only build and install one or more project subcomponents, we have provided the CMake option ``ARROW_OPTIONAL_INSTALL`` to only install targets that have been built. For example, if you only wish to build the Parquet libraries, its tests, and its dependencies, you can run: .. code-block:: shell cmake .. -DARROW_PARQUET=ON \ -DARROW_OPTIONAL_INSTALL=ON \ -DARROW_BUILD_TESTS=ON make parquet make install If you omit an explicit target when invoking ``make``, all targets will be built. Debugging with Xcode on macOS ----------------------------- Xcode is the IDE provided with macOS and can be use to develop and debug Arrow by generating an Xcode project: .. code-block:: shell cd cpp mkdir xcode-build cd xcode-build cmake .. -G Xcode -DARROW_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE=DEBUG open arrow.xcodeproj This will generate a project and open it in the Xcode app. As an alternative, the command ``xcodebuild`` will perform a command-line build using the generated project. It is recommended to use the "Automatically Create Schemes" option when first launching the project. Selecting an auto-generated scheme will allow you to build and run a unittest with breakpoints enabled.