diff --git a/doc/build-windows.md b/doc/build-windows.md index 0d96af26a..c415595e4 100644 --- a/doc/build-windows.md +++ b/doc/build-windows.md @@ -4,11 +4,14 @@ WINDOWS BUILD NOTES Below are some notes on how to build Bitcoin Core for Windows. Most developers use cross-compilation from Ubuntu to build executables for -Windows. Cross-compilation is also used to build the release binaries. +Windows. This is also used to build the release binaries. -Currently only building on Ubuntu Trusty 14.04 or Ubuntu Zesty 17.04 or later is supported. -Building on Ubuntu Xenial 16.04 is known to be broken, see extensive discussion in issue [8732](https://github.com/bitcoin/bitcoin/issues/8732). -While it may be possible to do so with work arounds, it's potentially dangerous and not recommended. +Building on Ubuntu Trusty 14.04 is recommended. +At the time of writing the Windows Subsystem for Linux installs Ubuntu Xenial 16.04. The default cross +compiler package for Ubuntu Xenial does not produce working executables for some of the bitcoin applications. +It is possible to build on Ubuntu Xenial by installing the cross compiler packages from +Ubuntu Zesty, see the steps below. +Building on Ubuntu Zesty 17.04 up to 17.10 has been verified to work. While there are potentially a number of ways to build on Windows (for example using msys / mingw-w64), using the Windows Subsystem For Linux is the most straightforward. If you are building with @@ -19,7 +22,7 @@ Compiling with Windows Subsystem For Linux ------------------------------------------- With Windows 10, Microsoft has released a new feature named the [Windows -Subsystem for Linux](https://msdn.microsoft.com/commandline/wsl/about). This +Subsystem for Linux (WSL)](https://msdn.microsoft.com/commandline/wsl/about). 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. @@ -28,6 +31,10 @@ 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](https://msdn.microsoft.com/en-us/commandline/wsl/install_guide). +For Windows 10 systems with the Fall Creators Update applied (version >= 16215.0) use the Windows Store +to install Ubuntu. Search for "Linux" in the Windows Store and install the free "Ubuntu" application. +Full instructions are available on the above link. + To get the bash shell, you must first activate the feature in Windows. 1. Turn on Developer Mode @@ -57,7 +64,7 @@ installing the toolchain will be different. First, install the general dependencies: - sudo apt-get install build-essential libtool autotools-dev automake pkg-config bsdmainutils curl + sudo apt install build-essential libtool autotools-dev automake pkg-config bsdmainutils curl git A host toolchain (`build-essential`) is necessary because some dependency packages (such as `protobuf`) need to build host utilities that are used in the @@ -65,20 +72,32 @@ build process. See also: [dependencies.md](dependencies.md). -If you're building on Ubuntu 17.04 or later, run these two commands, selecting the 'posix' variant for both, -to work around issues with mingw-w64. See issue [8732](https://github.com/bitcoin/bitcoin/issues/8732) for more information. -``` -sudo update-alternatives --config x86_64-w64-mingw32-g++ -sudo update-alternatives --config x86_64-w64-mingw32-gcc -``` - ## Building for 64-bit Windows -To build executables for Windows 64-bit, install the following dependencies: +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. - sudo apt-get install g++-mingw-w64-x86-64 mingw-w64-x86-64-dev +Common steps to install mingw32 cross compiler tool chain: -Then build using: + sudo apt install g++-mingw-w64-x86-64 + +Ubuntu Trusty 14.04: + + No further steps required + +Ubuntu Xenial 16.04 and Windows Subsystem for Linux [1](#footnote1),[2](#footnote2): + + sudo apt install software-properties-common + sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu zesty 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. + +Ubuntu Zesty 17.04 [2](#footnote2): + + sudo update-alternatives --config x86_64-w64-mingw32-g++ # Set the default mingw32 g++ compiler option to posix. + +Once the tool chain is installed the build steps are common: PATH=$(echo "$PATH" | sed -e 's/:\/mnt.*//g') # strip out problematic Windows %PATH% imported var cd depends @@ -92,7 +111,11 @@ Then build using: To build executables for Windows 32-bit, install the following dependencies: - sudo apt-get install g++-mingw-w64-i686 mingw-w64-i686-dev + sudo apt install g++-mingw-w64-i686 mingw-w64-i686-dev + +For Ubuntu Xenial 16.04, Ubuntu Zesty 17.04 and Windows Subsystem for Linux [2](#footnote2): + + sudo update-alternatives --config i686-w64-mingw32-g++ # Set the default mingw32 g++ compiler option to posix. Then build using: @@ -117,3 +140,20 @@ as they appear in the release `.zip` archive. This can be done in the following way. This will install to `c:\workspace\bitcoin`, for example: make install DESTDIR=/mnt/c/workspace/bitcoin + +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 distribution solves the issue, however, this is not +an officially supported approach and it's only recommended if you are prepared to reinstall WSL/Ubutntu should +something break. + +2: Starting from Ubuntu Xenial 16.04 both the 32 and 64 bit 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 code using the win32 version of the mingw-w64 cross compilers (at least not without +modifying headers in the bitcoin source code).