wdk-qt5

Qt 5.6.3 built with the WDK 7.1 toolchain — depends only on the system msvcrt.dll, runs on Windows XP, no Visual C++ redistributable, and consumable straight from CMake via find_package(Qt5) / FetchContent.

Overview

Qt 5.6.3 is the last Qt release that supports Windows XP. This repository builds a trimmed qtbase (the desktop-widgets essentials, no OpenGL/DBus/SQL) plus qtcharts and the lrelease / lupdate i18n tools with the Windows Driver Kit 7.1 toolchain (cl 15.00, the VS2008 SP1 compiler), using a recipe that links the dynamic system msvcrt.dll for the C runtime and statically links the C++ standard library. The result:

• depends only on DLLs that ship with Windows (msvcrt.dll, kernel32.dll, …) — no msvcr90.dll / msvcp90.dll, no VC++ redistributable to install;
• is built without Visual Studio — the WDK 7.1 toolchain is installed on a stock GitHub-hosted runner by tinysec/setup-wdk7;
• is published as prebuilt CMake packages that downstream projects pull with FetchContent, or can be built from source with the same one switch.

Features

• ✅ Zero redistributable — the only C runtime dependency is the system msvcrt.dll; PE subsystem version 5.00, so binaries load on Windows XP.
• ✅ A minimal desktop-widgets toolkit + Charts — Core, Gui, Widgets and Charts, plus Network, Xml, Concurrent, Test, PrintSupport; the qwindows platform plugin; image formats (PNG/JPEG/GIF/BMP/... built into Qt5Gui, plus an ICO plugin); and the qmake / moc / rcc / uic tools. OpenGL, DBus and SQL are disabled, and the QML/Quick, Multimedia, WebEngine, SVG, … modules are not built — this is a trimmed UI library, not the full Qt.
• ✅ i18n — runtime QTranslator / QLocale / tr() is in Core; the package also ships lrelease / lupdate to compile (.ts → .qm) and extract (source → .ts) translations.
• ✅ Static by default — links Qt into one self-contained .exe that depends only on msvcrt.dll; set QT5_SHARED=ON for DLLs. Four prebuilt variants: i386 / amd64 × shared / static.
• ✅ CMake-native — relocatable Qt5Config.cmake files; find_package(Qt5), AUTOMOC / AUTORCC / AUTOUIC all work.
• ✅ Prebuilt or from source — one boolean (QT5_FROM_SOURCE) switches between downloading a release asset and building locally.
• ✅ Floating release — a v5.6.3 alias tag/release always points at the latest CI build with stable asset URLs.
• ✅ No Visual Studio required, on the build side or the consumer side.

Prebuilt packages

Each CI build publishes:

Release	Marked	Asset names	Use for
v5.6.3.<build>	latest	qt-v5.6.3.<build>-wdk7-<link>-<arch>.zip	reproducible pin
v5.6.3 (alias)	—	qt-wdk7-<link>-<arch>.zip (stable URL)	track latest

<link> is shared or static; <arch> is i386 or amd64. Stable URL form:

https://github.com/tinysec/wdk-qt5/releases/download/v5.6.3/qt-wdk7-<link>-<arch>.zip

Each .zip is an install prefix (bin/, lib/, include/, plugins/, lib/cmake/).

Use in CMake

Consuming Qt requires the setup-wdk7 toolchain (so your own code is built with the same WDK 7.1 CRT recipe) plus this repo's cmake/qt5.cmake helper.

1. Configure with the WDK7 toolchain

In your CI / build command:

cmake -S . -B build -G "NMake Makefiles" \
  -DCMAKE_TOOLCHAIN_FILE=<setup-wdk7>/cmake/wdk7.cmake \
  -DWDK7_ARCH=i386            # or amd64
cmake --build build

On GitHub Actions, add the toolchain step:

- uses: tinysec/setup-wdk7@v1
  id: wdk7
# then pass ${{ steps.wdk7.outputs.toolchain-file }} as CMAKE_TOOLCHAIN_FILE

2. Pull Qt in your CMakeLists.txt

Vendor cmake/qt5.cmake (or file(DOWNLOAD …) it), then:

include(qt5.cmake)

# Default is STATIC: one self-contained .exe depending only on msvcrt.dll, which
# is the point of this XP/zero-redist build. Set QT5_SHARED=ON for DLLs.
qt5_provide()             # QT5_ARCH follows WDK7_ARCH; sets CMAKE_PREFIX_PATH

find_package(Qt5 5.6 REQUIRED COMPONENTS Core Widgets)

set(CMAKE_AUTOMOC ON)
add_executable(app WIN32 main.cpp)
target_link_libraries(app Qt5::Core Qt5::Widgets)
qt5_deploy(app)           # copies Qt DLLs next to the exe (no-op when static)

# A static Qt build needs the platform plugin imported explicitly:
if(NOT QT5_SHARED)
    target_link_libraries(app Qt5::QWindowsIntegrationPlugin)
    # and Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin) in your source
endif()

Static (the default) links Qt into the executable: a single app.exe that depends only on the system msvcrt.dll — nothing to deploy. With QT5_SHARED=ON you get Qt DLLs; qt5_deploy(app) then copies them (and the platform plugin) next to the .exe so it runs without putting the Qt bin/ on PATH.

Options

Option	Type	Default	Meaning
QT5_SHARED	BOOL	OFF	OFF = static self-contained .exe, ON = shared DLLs
QT5_FROM_SOURCE	BOOL	OFF	OFF = download prebuilt, ON = build from source
QT5_ARCH	STRING	follows WDK7_ARCH	i386 or amd64

Translations (i18n)

Runtime translation is built in (QTranslator, QLocale, tr()). To author your own translations, the package ships lrelease / lupdate in bin/:

lupdate main.cpp -ts app_zh_CN.ts   # extract tr() strings into a .ts
# ... translate app_zh_CN.ts ...
lrelease app_zh_CN.ts               # compile the .ts into app_zh_CN.qm

Image formats

PNG, BMP, JPEG, GIF, PBM/PGM/PPM, XBM/XPM are built into Qt5Gui and work with no extra setup — in the static build they are linked right into your .exe. ICO is the one format that stays a separate plugin; a static app that loads .ico must import it:

#include <QtPlugin>
Q_IMPORT_PLUGIN(QICOPlugin)   // static only; link Qt5::QICOPlugin too

For a shared build, JPEG/GIF/ICO are DLL plugins under plugins/imageformats/; qt5_deploy() copies them next to the executable.

Build it yourself

The build is driven by plain scripts under hack/wdk-qt/ (each respects QT_ARCH = i386/amd64 and QT_LINK = shared/static):

set QT_ARCH=i386
set QT_LINK=static
hack\wdk-qt\clean-build.bat     :: configure + build qtbase into build-wdk-qtbase-i386-static
hack\wdk-qt\install.bat         :: nmake install (+ patch static CMake deps, drop QtSql)
hack\wdk-qt\build-qtcharts.bat  :: build Qt5Charts into the same prefix
hack\wdk-qt\build-i18n.bat      :: build lrelease/lupdate into the prefix bin/

The WDK is located via W7BASE / WDK7_ROOT (set by setup-wdk7), falling back to C:\WinDDK\7600.16385.1.

How it works

• A custom mkspec win32-wdk7-msvc2008 plus a force-included wdk-compat.h supply the CRT shims the WDK omits (the system msvcrt.dll is VC6-era), and link ntstc_msvcrt.lib for the statically-linked C++ standard library.
• Self-contained shim headers replace SDK/compiler headers the WDK lacks (intrin.h, windns.h, commoncontrols.h, …).
• A handful of small, guarded qtbase source patches handle gaps in the old STL70 headers and the 32-bit-time_t CRT.
• configure disables OpenGL, DBus and SQL (-no-opengl -no-dbus -no-sql-sqlite); the QtSql lib body, which Qt 5.6 always builds, is deleted after install. Network and Xml are kept (useful for GUI apps; note no HTTPS, since -no-openssl).
• qtcharts is vendored and built with the same mkspec/shims (only syncqt is needed for its forwarding headers). For the static build, the plugin import targets are patched so a GUI app links the platform plugin cleanly.
• The i18n tools come from the vendored qttools/src/linguist; lupdate gets an asInvoker manifest force-embedded so Windows installer-detection does not flag its update name and demand elevation.

License

Qt 5.6.3 is licensed under LGPLv2.1 / LGPLv3 (and GPL); see the LICENSE.* files. The build tooling in this repository is provided under the same terms.