# Building SWI-Prolog using Emscripten for WebAssembly (WASM)

As of version 8.1.2, building an executable  for WASM is fully supported
by the standard build process. The port   is the work of Raivo Laanemets
and  related  material   can   be   found    mostly   on   his   [GitHub
pages](https://github.com/).

## Preparation

You need to download the Emscripten  compiler. Follow the instruction on
its
[homepage](http://kripken.github.io/emscripten-site/docs/getting_started/downloads.html).

After the successful installation load the Emscripten environment into the current terminal session (adjust path):

    source ./emsdk_env.sh

## Dependencies

SWI-Prolog depends on zlib. To compile it to WebAssembly:

    wget https://zlib.net/zlib-1.2.11.tar.gz -O "$HOME/zlib-1.2.11.tar.gz"
    tar -xf "$HOME/zlib-1.2.11.tar.gz" -C "$HOME"
    cd "$HOME/zlib-1.2.11"
    emconfigure ./configure
    emmake make

This will download and build zlib   into the zlib-1.2.11 subdirectory in
your home directory.

## Building

See
[CMAKE.md](https://github.com/SWI-Prolog/swipl-devel/blob/master/CMAKE.md)
in the top directory of the sources.

@see https://github.com/SWI-Prolog/swipl-wasm