bbs_build_env¶

Introduction¶

bbs_build_env is a tool that can be used to simplify the process of selecting a compiler and managing multiple build flavors.

More specifically, the tool helps solve the following problems when using CMake:

CMake does not create the output directory for build artifacts. The script evaluates the system and build configuration and creates easily identifiable name for the build directory that is used by other build scripts.
Setting a compiler configuration under Windows OS ( which is significantly different from Unix )

Prerequisites and Supported Platforms¶

bbs_build_env requires:

Python 3.6+

bbs_build_env is supported on all platform where the CMake based build system is supported.

On Windows, bbs_build_env is not supported by the windows command prompt. Instead, you must use the tool through Git bash(msysgit). See the tutorial for more details (TODO).

How It Works¶

bbs_build_env prints a list of Bourne shell commands to set environment variables known to bbs_build, so that configuration options do not need to be manually provided. The end result is that the build output directory, compiler, and installation prefix are unique for each build configuration.

Important

Since the bbs_build_env prints shell commands to the standard output, the output must be executed by the current Bourne shell using the eval command.

Usage Examples¶

eval `bbs_build_env -p gcc-9.0.0 -u dbg_64 -i ~/bde-install`

Set up the environment variables so that the bbs_build build tool uses the build profile named gcc-9.0.0 (assuming that build profile with this name exist), builds with the UFID configuration ‘dbg_64’ to the output directory <uplid>-<ufid>, and install the libraries to a installation prefix of ~/bde-install/.

For example, on my system, the uplid was unix-linux-x86_64-2.6.32-gcc-9.0.0, and unix-linux-x86_64-2.6.32-gcc-9.0.0-dbg_64 was the name of the build output directory.

Environment Variables Set by bbs_build_env¶

The following environment variables may be set by evaluating the output of bde_setwafenv.py:

CXX

The path to the C++ compiler.
CC

The path to the C compiler.
BBS_ENV_MARKER

Flag to use BBS build system in the dual-mode CMakeLists.txt (this flag is transitional tool to support both old and new build systems and will be removed once the transition is completed )
BDE_CMAKE_TOOLCHAIN

The path to the CMake toolchain. If the toolchain file is set, it will override the CXX and CC variables during CMake configuration step.
BDE_CMAKE_UFID

The UFID to use.
BDE_CMAKE_UPLID

The UPLID determined by bbs_build_env. Note that UPLID is primarily used to setup compile environment for Windows.
BDE_CMAKE_BUILD_DIR

The path in which build artifacts will be generated. This will be set to the expanded value of "$BDE_CMAKE_UPLID-$BDE_CMAKE_UFID, so that build directory is unique for each build configuration.
PREFIX

The installation prefix.

Commands and Options¶

Commands¶

By default, bbs_build_env will print the Bourne shell commands to set environment variables.

It also provides 3 other optional commands:

unset¶: Print Bourne shell commands to unset any environment variables that might be set previously by bbs_build_env.

list¶: List the available build profiles.

set¶: Print Bourne shell commands to set environment variables. This is the default command if none is specified. The section Set Command Options documents the options available for this command.

Set Command Options¶

-p, --profile¶: Specify the compiler profile to use.

-u, --ufid¶: Specify the build configuration using a UFID.

--build-type¶: Specify the CMake native build type (Debug/Release/RelWithDebInfo).

--abi-bits¶: Specify the build bitness.

Note

--ufid option superseds --build-type and --abit-bits options (the latter will be ignored). Also note that the CMake build types are translated into ufid for low level build system.

-b, --build-dir¶: Specify the build directory.

-i, --install-dir¶: Specify the “root installation directory”.

Use the --help option for more information.