qTox/windows/cross-compile/README.md

Cross-compile from Linux to Windows

Intro

Following these instructions will show you how to cross-compile qTox for Windows.

This script can be used by qTox users and devs to compile qTox for windows themselves.

Please note that the compilation script doesn't build the updater and doesn't produce an installer.

Usage

1. Install Docker.

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2. Create 3 directories for storing the files needed for cross-compiling.

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• workspace -- a directory that will contain a cache of qTox dependencies and the final qTox cross-compilation build. You should create this directory.

• script -- a directory that contains the build.sh script. Copy the build.sh script to this folder.

• qtox -- the root directory of a qTox repository. This directory must contain the qTox source code that will be cross-compiled. You can use an existing qTox directory you've been using for development or check one out using git clone https://github.com/qTox/qTox.git folder-name

These directories will be mounted inside a Docker container at/workspace, /scriptand/qtox.

The contents of qtox and script directories are not modified during compilation. The build.sh script makes a temporary copy of the qtox directory for compilation.

3. Create the docker container and run the build script.

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Note that thebuild.shscript takes 2 arguments: architecture and build type. Valid values for the architecture are i686 for 32-bit and x86_64 for 64-bit. Valid values for the build type are release and debug. All case sensitive. You can modify the scripts below to fit your use case. To create the docker container and start cross-compiling run

sudo docker run --rm \
-v /absolute/path/to/your/workspace:/workspace \
-v /absolute/path/to/your/script:/script \
-v /absolute/path/to/your/qtox:/qtox \
debian:stretch-slim \
/bin/bash /script/build.sh i686 release

If you are a qTox developer, you might want to enable tty and leave stdin open by running the following script instead.

sudo docker run -it \
--rm \
-v /absolute/path/to/your/workspace:/workspace \
-v /absolute/path/to/your/script:/script \
-v /absolute/path/to/your/qtox:/qtox \
debian:stretch-slim \
/bin/bash /script/build.sh i686 release

These will cross-compile all of the qTox dependencies and qTox itself, storing them in the workspace directory. The first time you run it for each architecture, it will take a long time for the cross-compilation to finish, as qTox has a lot of dependencies that need to be cross-compiled.

Note that it takes my Intel Core i7 processor about 125 minutes on average for the cross-compilation to finish on a single core, and about 30 minutes using all 8 hyperthreads. Once you've compiled it, the dependencies will be cached inside the workspace directory. The next time you build qTox, the build.sh script will skip recompiling them which is a lot faster -- about 8 minutes on a single core and 2 minutes using 8 hyperthreads.

4. After cross-compiling has finished

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The workspace\i686\qtox and workspace\x86_64\qtox\directories will contain the compiled binaries in their respective debug or release folder depending on the compilation settings you chose in Step 3.

The dep-cache directory is where all the cross-compiled qTox dependencies will be cached for the future builds. You can remove any directory inside the deps folder, which will result in the build.sh re-compiling the removed dependency.

The workspace direcory structure for reference

workspace
├── i686
│   ├── dep-cache
│   │   ├── libffmpeg
│   │   ├── libfilteraudio
│   │   ├── libopenal
│   │   ├── libopenssl
│   │   ├── libopus
│   │   ├── libqrencode
│   │   ├── libqt5
│   │   ├── libsodium
│   │   ├── libsqlcipher
│   │   ├── libtoxcore
│   │   └── libvpx
│   └── qtox
│       ├── debug
│       └── release
└── x86_64
    ├── dep-cache
    │   ├── libffmpeg
    │   ├── libfilteraudio
    │   ├── libopenal
    │   ├── libopenssl
    │   ├── libopus
    │   ├── libqrencode
    │   ├── libqt5
    │   ├── libsodium
    │   ├── libsqlcipher
    │   ├── libtoxcore
    │   └── libvpx
    └── qtox
        ├── debug
        └── release