Qt static linking and deployment

I am trying to deploy(release to public) a simple qt application I made recently, but got stuck at static linking qt libs.

I followed the guide on qt docs to re-build qt and my app statically. But the release build still require qtgui / qtcore dll for no apparent reasons, I wonder if anyone has seen this kind of problems before ? Or even better, has successfully resolved it ?

http://doc.qtsoftware.com/4.5/deployment-windows.html

I wrote a guide to static linking

and How to build Qt static with multiple compilers and keep it small

(because it can get pretty big, especially for simple programs). You may also want to check out the BitRock installer, which is free for open source projects.

In short, it turns out to be a little more complex if you are using anything Qt thinks of as a plugin, such as support for most image types (JPEG, GIF) or databases. For example, if you want to include support for Oracle DBMS and GIF images for your icons, you add the following to your .PRO file:

QTPLUGIN += qsqloci qgif
CONFIG += static

You will then need to:

#include <QtPlugin>

in your project, and import any plugins used. You need to change these settings back order to get it to compile with dynamic linking again (like when debugging or adding features), though this can be easily automated. There are also considerations when building the Qt libraries for use with static linking, though the Qt instructions will at least get you started.

With Qt 5.5, things are quite easy. There's the configure script you have to run before building Qt. There are following orthogonal settings that you pass to configure:

0. Do you want a static Qt library?

-static option should be passed to configure

1. Do you want the build of Qt, and of your application, to use a static C++ runtime?

-static-runtime option should be passed to configure

2. Do you want XP targeting?

-target xp option should be passed to configure

Additionally, follow the instructions from this blog post.

Qt Creator didn't support XP targeting automagically at least until v.3.5.0 since it doesn't set up the environment for the build tools properly. You have to modify the build environment manually per the blog post.

Also, be aware that your static build will still link to the visual studio runtimes dynamically!

See this faq (internet archive link, in case the link goes away) :

> Why does a statically built Qt use the dynamic Visual Studio runtime libraries ? Do I need to deploy those with my application ? > > Qt is built using the -MD(d) switch, which links against the dynamic C/C++ runtime libraries. This is necessary as we have experienced memory problems when using anything but the -MD(d) flag, and in general, it is recommended to use. You should not alter this flag yourself for your application, because it conflicts with how the Qt library is built if you change the flag to -MT. You should not change it for Qt either, since it is likely to cause problems. > > Qt is still built statically when using the -static option though, meaning you do not need to distribute the Qt dlls when deploying your application. You will have to distribute the C runtimes though (if they don't already exist on the target machine), see our deployment documentation http://doc.qt.io/qt-5/windows-deployment.html#application-dependencies.

msys2 has a pre-built static Qt5 package

e.g. pacman -S mingw-w64-qt5-static

Currently, to also get all dependencies of Qt statically linked, with CMake, you need to add:
list(PREPEND CMAKE_FIND_LIBRARY_SUFFIXES .a .lib)
before calling find_package(Qt5 …

---

CMAKE_AUTOSTATICPLUGINS was replaced by a new upstream implementation and is not needed anymore.

I just compiled an application statically (Debug) with QT Plugins(5.9), with VS (2015) (Win).

a) Add to your code.

#include <QtPlugin>
Q_IMPORT_PLUGIN (QWindowsIntegrationPlugin);

b) Add the following to the link paths

\5.9.0_x86_static_install\lib
\5.9.0_x86_static_install\bin
\5.9.0_x86_static_install\plugins
\5.9.0_x86_static_install\plugins\platforms
\5.9.0_x86_static_install\plugins\imageformats

c) Add the list of QT static libraries and internal VS libraries to your link list.

version.lib
imm32.lib
shlwapi.lib
rpcrt4.lib
Ws2_32.lib
Mpr.lib
Netapi32.lib
Rpcrt4.lib
Iphlpapi.lib
winmm.lib
gdi32.lib
advapi32.lib
msimg32.lib
UxTheme.lib
translatord.lib
preprocessord.lib
d3d9.lib
dxguid.lib
libEGLd.lib
libGLESv2d.lib
iphlpapi.lib
psapi.lib
ws2_32.lib
Dwmapi.lib
Qt5CoreD.lib
Qt5Guid.lib
Qt5Xmld.lib
Qt5Widgetsd.lib
Qt5Networkd.lib
Qt5Winextrasd.lib
Qt5PlatformCompositorSupportd.lib
qicod.lib
qtmaind.lib
qtlibpngd.lib
qtharfbuzzd.lib
qtpcre2d.lib
qwindowsd.lib
Qt5FontDatabaseSupportd.lib
Qt5ThemeSupportd.lib
Qt5EventDispatcherSupportd.lib
Qt5AccessibilitySupportd.lib
qtfreetyped.lib

Kevin Higgins

I recommend you to use linuxdeployqt this tool. It can help solve most of the dependency problems. And I use it to package my qt application successfully.

This answer applies to using MSYS2 with mingw-w64 as the compiler, in Windows, and qmake. The QT version is 5.15.0.

---

Installing the package qt5-static gives you a build of QT that produces executables who don't rely on any QT DLLs. (Example commandline - pacman -Ss mingw64/mingw-w64-x86_64-qt5-static).

However a new problem is introduced here: it does not pass the -static flag to gcc. Meaning that although the executable does not depend on QT DLLs, it does depend on libgcc-s, libwinpthread.dll etc.

Normally, this problem would be fixed by using CONFIG += static which causes qmake to pass -static to gcc. However, and as noted in the other answers, for a qt-static build that config option is ignored!

To solve this I had to manually specify the gcc flags for static linking in the qmake file, i.e. :

QMAKE_CXXFLAGS += -static
QMAKE_LFLAGS_WINDOWS += -static

Which results in a (large) binary with no external dependencies other than Windows system DLLs.

(In case it matters: my use case was building a COM in-process server DLL that should have no external dependencies; I was also using TEMPLATE=lib and CONFIG += dll).