WINDOWS BUILD NOTES

Below are some notes on how to build Bitcoin ABC for Windows.

The options known to work for building Bitcoin ABC on Windows are:

Other options which may work, but which have not been extensively tested are (please contribute instructions):

In any case please make sure that the compiler supports C++17.

Installing Windows Subsystem for Linux

With Windows 10, Microsoft has released a new feature named the Windows Subsystem for Linux (WSL). This feature allows you to run a bash shell directly on Windows in an Ubuntu-based environment. Within this environment you can cross compile for Windows without the need for a separate Linux VM or server. Note that while WSL can be installed with other Linux variants, such as OpenSUSE, the following instructions have only been tested with Ubuntu Bionic.

This feature is not supported in versions of Windows prior to Windows 10 or on Windows Server SKUs. In addition, it is available only for 64-bit versions of Windows.

Full instructions to install WSL are available on the above link. To install WSL on Windows 10 with Fall Creators Update installed (version >= 16215.0) do the following:

  1. Enable the Windows Subsystem for Linux feature
    • Open the Windows Features dialog (OptionalFeatures.exe)
    • Enable ‘Windows Subsystem for Linux’
    • Click ‘OK’ and restart if necessary
  2. Install Ubuntu
    • Open Microsoft Store and search for Ubuntu or use this link
    • Click Install
  3. Complete Installation
    • Open a cmd prompt and type “Ubuntu”
    • Create a new UNIX user account (this is a separate account from your Windows account)

After the bash shell is active, you can follow the instructions below, starting with the “Cross-compilation” section. Compiling the 64-bit version is recommended, but it is possible to compile the 32-bit version.

Cross-compilation for Ubuntu and Windows Subsystem for Linux

At the time of writing the Windows Subsystem for Linux installs Ubuntu Bionic 18.04. The steps below can be performed on Ubuntu (including in a VM) or WSL. The depends system will also work on other Linux distributions, however the commands for installing the toolchain will be different.

First, install the general dependencies:

sudo apt update
sudo apt upgrade
sudo apt install autoconf automake build-essential bsdmainutils curl git libboost-dev libevent-dev libssl-dev libtool ninja-build pkg-config python3 python-pytest

The cmake version packaged with Ubuntu Bionic is too old for building Building Bitcoin ABC. To install the latest version:

sudo apt-get install apt-transport-https ca-certificates gnupg software-properties-common wget
wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | sudo apt-key add -
sudo apt-add-repository 'deb https://apt.kitware.com/ubuntu/ bionic main'
sudo apt update
sudo apt install cmake

A host toolchain (build-essential) is necessary because some dependency packages (such as protobuf) need to build host utilities that are used in the build process.

See also: dependencies.md.

Building for 64-bit Windows

The first step is to install the mingw-w64 cross-compilation tool chain. Due to different Ubuntu packages for each distribution and problems with the Xenial packages the steps for each are different.

Common steps to install mingw32 cross compiler tool chain:

sudo apt install g++-mingw-w64-x86-64

Ubuntu Xenial 16.04 and Windows Subsystem for Linux 1,2:

sudo apt install software-properties-common
sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu artful universe"
sudo apt update
sudo apt upgrade
sudo update-alternatives --config x86_64-w64-mingw32-g++ # Set the default mingw32 g++ compiler option to posix.
sudo update-alternatives --config x86_64-w64-mingw32-gcc # Set the default mingw32 gcc compiler option to posix.

Ubuntu Artful 17.10 2 and later, including Ubuntu Bionic on WSL:

sudo update-alternatives --config x86_64-w64-mingw32-g++ # Set the default mingw32 g++ compiler option to posix.
sudo update-alternatives --config x86_64-w64-mingw32-gcc # Set the default mingw32 gcc compiler option to posix.

Once the toolchain is installed the build steps are common:

Note that for WSL the Bitcoin ABC source path MUST be somewhere in the default mount file system, for example /usr/src/bitcoin-abc, AND not under /mnt/d/. This means you cannot use a directory that is located directly on the host Windows file system to perform the build.

Acquire the source in the usual way:

git clone https://github.com/Bitcoin-ABC/bitcoin-abc.git

Once the source code is ready the build steps are below:

PATH=$(echo "$PATH" | sed -e 's/:\/mnt.*//g') # strip out problematic Windows %PATH% imported var
cd depends
make build-win64
cd ..
mkdir build
cd build
cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/Win64.cmake -DBUILD_BITCOIN_SEEDER=OFF # seeder not supported in Windows yet
ninja

Depends system

For further documentation on the depends system see README.md in the depends directory.

Installation

After building using the Windows subsystem it can be useful to copy the compiled executables to a directory on the Windows drive in the same directory structure as they appear in the release .zip archive. This can be done in the following way. This will install to c:\workspace\bitcoin-abc, for example:

cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/Win64.cmake -DBUILD_BITCOIN_SEEDER=OFF -DCMAKE_INSTALL_PREFIX=/mnt/c/workspace/bitcoin-abc
ninja install

Footnotes

1: There is currently a bug in the 64 bit Mingw-w64 cross compiler packaged for WSL/Ubuntu Xenial 16.04 that causes two of the bitcoin executables to crash shortly after start up. The bug is related to the -fstack-protector-all g++ compiler flag which is used to mitigate buffer overflows. Installing the Mingw-w64 packages from the Ubuntu 17.10 distribution solves the issue, however, this is not an officially supported approach and it’s only recommended if you are prepared to reinstall WSL/Ubuntu should something break.

2: Starting from Ubuntu Xenial 16.04, the Mingw-w64 packages install two different compiler options to allow a choice between either posix or win32 threads. The default option is win32 threads which is the more efficient since it will result in binary code that links directly with the Windows kernel32.lib. Unfortunately, the headers required to support win32 threads conflict with some of the classes in the C++11 standard library, in particular std::mutex. It’s not possible to build the Bitcoin ABC code using the win32 version of the Mingw-w64 cross compilers (at least not without modifying headers in the Bitcoin ABC source code).