Qt static linking and deployment

Question

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

Answer 1

With Qt 5.5, things are quite easy. There are following orthogonal settings that you pass to configure when building Qt:

1. Do you want a static Qt library?

   -static option should be passed to configure

2. 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

3. 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.

Answer 2

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.

Answer 3

msys2 has a pre-built static Qt5 package

… which, using CMake, when the CMAKE_AUTOSTATICPLUGINS target property is set, also links all available plugins. (this, currently, is only enabled through downstream patches, unofficial, but it reaches the goal)

If you use qmake this at least spares you the effort to build it yourself .

Answer 4

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

Answer 5

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.

Answer 6

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.