Compiling the igraph C library to WebAssembly

Overview

This repository compiles the igraph C library to Wasm binaries that can be quickly linked to other object files. The aim is to avoid a tedious re-compilation process for each individual Wasm project, especially when only a small part of igraph's functionality is required. For example, compiling igraph takes up over half of the build time of scran.js, so providing prebuilt binaries can greatly streamline the CI/CD iterations.

Usage of these binaries implies acceptance of the igraph license, see here for more details.

Quick start

Developers can fetch the libigraph.a static library from the Releases page along with the required headers. This contains the contents of the directory created by running make install in the igraph build directory. We also add our own CMakeLists.txt for convenient linking with CMake's FetchContent:

FetchContent_Declare(
  igraph
  URL https://github.com/LTLA/igraph-wasm/releases/download/v0.1.1_3.1.25/igraph-0.9.4-wasm.tar.gz
  URL_HASH SHA256=efe59e45472c04b51eee73bc950e5cbcb2d67e859fe93bab927188b3f31cb18f
)
FetchContent_MakeAvailable(igraph)

# Simply link igraph-wasm to your target:
target_link_libraries(my_exe igraph)

Versioning

We use several types of version numbers.

• Most obviously, the version of the igraph C library itself is recorded in the name of the release tarball.
• The version of Emscripten used to compile the library is recorded in the second half of the tag name corresponding to the release. Different Emscripten versions are not necessarily ABI-compatible, so best results are obtained by picking the same Emscripten version that is used for the to-be-linked project.
• The version of this repository is recorded in the first half of the tag name. Different versions of this repository may use different configurations for Wasm compilation.

So, for example, a tag name with v0.1.0_3.1.25 means that version v0.1.0 of this repository was compiled with Emscription 3.1.25. This may then be associated with multiple tarballs for different versions of the igraph C library.

See also

This setup was inspired by the libhdf5-wasm repository, which does the same thing for the HDF5 library.