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Compiling code in a Conda environment

Use the pre-built environments

The Pre-built environments should contain all of the packages needed to build most things, if packages are missing please open a Request ticket to request their addition.

Installing a compiler

To compile packages into a conda environment, it is recommended to install all of the build tools into that environment, including the necessary compiler toolchain. With conda-forge, this is simplified by a series of metapackages that can be used to install the right compiler for the given language:

Language Package name
C c-compiler
C++ cxx-compiler
Fortran fortran-compiler

Example: installing the C++ compiler package

conda install cxx-compiler

On Linux the above command will install the GNU C++ compiler (g++), while on macOS this will install Clang.

Installation prefices

Conda's environment configuration means that dynamic linking is much more tightly controlled than typically done on other platforms. This means that, for example, building shared object libraries and installing them into custom directories that you append to environment variables such as LD_LIBRARY_PATH may not resolve links properly.

The way to avoid this is simply to always install code directly into a conda environment.

With autotools you should use

./configure --prefix=${CONDA_PREFIX} ...

With CMake the conda-forge compilers provide an environment variable ${CMAKE_ARGS} that includes the basics needed to configure CMake properly:

cmake . ${CMAKE_ARGS} ...

With meson the conda-forge compilers provide an environment variable ${MESON_ARGS} that includes the basics needed to configure meson properly:

meson setup . ${MESON_ARGS} ...

With Python (or Pip) you shouldn't need to manually specify any paths, just make sure you are using the right Python installation:

python -m pip install .

Installing the macOS SDK

Conda compilers will try and compile software for the oldest compatible version of macOS, which is 10.9 most of the time. So, you will likely need to install the MacOSX10.9 SDK, which you can do as follows:

curl -L -O
mkdir -p /opt
tar -xf MacOSX10.9.sdk.tar.xz -C /opt

Using /opt is just a convention

You can store the SDK wherever you like, using /opt is just a convention.

Then, set the CONDA_BUILD_SYSROOT environment variable to match the new SDK:

export CONDA_BUILD_SYSROOT="/opt/MacOSX10.9.sdk"

If you indend to use conda-build to test package builds, you should also add the SDK path to your global ~/conda_build_config.yaml file:

  - /opt/MacOSX10.9.sdk  # [osx]