JlCxx

This is the C++ library component of the CxxWrap.jl package, distributed as a regular CMake library for use in other C++ projects. To build a Julia interface to a C++ library, you need to build against this library and supply the resulting library as a binary dependency to your Julia package. The testlib-builder directory contains a complete example of how to build and distribute these binaries, or you can use the BinaryBuilder.jl wizard to generate the builder repository.

Building libcxxwrap-julia

Building libcxxwrap-julia requires a C++ compiler which supports C++17 (e.g. GCC 7, clang 5; for macOS users that means Xcode 9.3).

The main CMake option of interest is Julia_PREFIX, which should point to the Julia installation you want to use. The PREFIX is a directory, one containing the bin and lib directories and so on. If you are using a binary download of Julia (https://julialang.org/downloads/), this is the top-level directory; if you build Julia from source (https://github.com/JuliaLang/julia), it would be the usr directory of the repository. Below we will call this directory /home/user/path/to/julia, but you should substitute your actual path in the commands below.

On Linux or Mac, the sequence of commands to follow is:

git clone https://github.com/JuliaInterop/libcxxwrap-julia.git
mkdir libcxxwrap-julia-build
cd libcxxwrap-julia-build
cmake -DJulia_PREFIX=home/user/path/to/julia ../libcxxwrap-julia
cmake --build . --config Release

Instead of specifying the prefix, it is also possible to directly set the Julia executable, using:

cmake -DJulia_EXECUTABLE=/home/user/path/to/julia/bin/julia ../libcxxwrap-julia

Next, you can build your own code against this by setting the JlCxx_DIR CMake variable to the build directory (libcxxwrap-julia-build) used above, or add it to the CMAKE_PREFIX_PATH CMake variable.

Using the compiled libcxxwrap-julia in CxxWrap

Since CxxWrap v0.10, binaries are managed through the libcxxwrap_julia_jll JLL package. To use your own binaries, you need to set up an overrides file, by default at ~/.julia/artifacts/Overrides.tomlor %HOMEDRIVE%\%HOMEPATH%\.julia\artifacts\Overrides.toml, with the following contents:

[3eaa8342-bff7-56a5-9981-c04077f7cee7]
libcxxwrap_julia = "/path/to/libcxxwrap-julia-build"

The file can be generated automatically using the OVERRIDES_PATH, OVERRIDE_ROOT and APPEND_OVERRIDES_TOML Cmake options, with the caveat that each CMake run will append again to the file and make it invalid, i.e. this is mostly intended for use on CI (see the appveyor and travis files for examples).

Building on Windows

On Windows, building is easiest with Visual Studio 2019, for which the Community Edition with C++ support is a free download. You can clone the https://github.com/JuliaInterop/libcxxwrap-julia.git repository using the built-in git support, and configure the Julia_PREFIX option from the built-in CMake support. See the Visual Studio docs for more info. Use Julia version 1.3.1, otherwise building will fail with "no target architecture" error (see issue julia/34201).

See the CxxWrap.jl README for more info on the API.

Binaries for the main branch

Binaries for the main branch are published at https://github.com/barche/libcxxwrap_julia_jll.jl, you can install them (in Pkg mode, hit ]) using:

add https://github.com/barche/libcxxwrap_julia_jll.jl.git