I am running in situation where I have two different versions of Qt installed, the compiled with mingw one, and the other with visual studio.
Now, When I compile my program with Qt MinGW version and run it, I got a message have scrambled text, saying that one of essential Qt modules not loaded.
My question is, how I can set the path to Qt essential modules for my application with C++. I looked at documentation and found addLibraryPath method but it seems like for Qt plugins only.
Edit
It seems I misunderstood the question, as SIFE comment that he needs to load Qt modules (like QtGui4.dll), not plugins. The answer for plugins is left here, in case it might help someone.
Plugins
Qt loads plugins that are in the SDK/plugins by default. The problem is, it finds the wrong SDK first...
If I remember right, Qt first search in the directory .. So you can copy the 'plugins' directory near your *.exe : plugins for msvc copied near the msvc-compiled exe, and plugins for gcc near gcc-compiled exe.
If you do not want to copy the plugins directory, you can use setLibraryPaths (not tested, but might work)
Last but not least, you can also use the qt.conf approach.
Modules
Modules are not dynamically loaded, in the sense that they're part of the dependencies of the application, so they are loaded at exe startup, and not via LoadLibrary. So, the solution is simple: just copy the dlls in the same folder than the one containing the *.exe
Concerning compiler, the proper library/include settings should be done by QMake.
QMake creates your makefile/VS-Project using the libraries found in the same Version Qmake belongs to.
Try calling QMake using the complete path explicitely for each Qt-Version
e.g.
c:/myQtMinGwProject>c:/Qt4_mingw/bin/qmake
c:/myQtVSProject>c:/Qt4_VS2008/bin/qmake -t vcapp
Concerning run-time, make sure the dlls for corresponding version are in PATH
I hope it helps
Related
I have written windows gui application using qt and i want to deploy it.Now when i place .exe to other PC it shows error which says that qt5core.dll and etc required.I can install this dll,but is it possible to run exe app with qt without qt's dll as one file?So i can for example give .exe to my friend and he can instantly run it without installing .dll?
Basically, if you want a single exe file, you probably mean static linking.
The legal commercial version makes it possible or if I am not wrong, you will have to build a static qt version.
In the latter case, you will have to provide the source code of your application.
I do this sometimes, but you'll have to be careful with the license requirements: if you go with GPL, it should be OK, if you choose LGPL, it may be a bit less simple. No idea about the commercial version.
What you must do is building Qt statically, and then use that Qt build to build your application. I had a good experience with mxe. MXE builds an entire crossbuild environment and allows you to build your big Qt exe statically. I used it on Mac OS and Linux to build static executables for Windows, but you can probably run it on WSL. It takes a bit to compile, but it is simple to use. Please note that it cannot be used if your app needs QtWebEngine as it won't build with mingw.
Another simpler option is to create an installer. The Qt installer framework is simple to use. If you include the VS runtime, you end up with a single exe to distribute (the installer).
You always need to include the libraries you use (including your compilers runtime libraries in fact) when you deploy your executable - otherwise how would your application be able to use the code in those libraries? You may be able to statically link some/most things, but rarely everything. Look into how to create an installer / package for your application, so you can bundle up everything as one convenient file.
You can buid you app using QT Static (a large .exe file, no external dependencies)
If you are using LGPL Qt, you must read this:
https://www.qt.io/faq/3.7.-what-are-my-obligations-when-using-qt-under-the-lgpl
Yo can use Qt and static linking, but "The user of your application has to be able to re-link your application against a different or modified version of the Qt library"
You can use an application template like this, very useful for LGPL Qt:
https://marketplace.qt.io/products/qt-lgpl-app-template
So I've finished my Qt application, and I need to implement testing using the Squish testing application (first time using). Apparently I require a working exe file, but I can't get the executable to run. I added all the .dll files to the same directory, only to get the error:
Prior to that I was getting errors saying that XXXX.dll is missing, but like I said, I've added them to the directory. I've tried using both debug and release builds of my project with the same results. I've also tried building a stand-alone executable, but that has it's own problems (one thing at a time). The program runs great in Qt Creator and VS2013...just not on its own.
Any solutions to this?
EDIT:
From Dependency Walker...
0x7B is the error code for invalid image format.
You're either trying to run a 64-bit application on a 32-bit system, or linking to a 64-bit library (ie you copied the wrong DLLs).
Or your binaries are just corrupted.
If you run the application standalone (i.e. not from Qt Creator) you also need the Qt library DLLs. which one you need, depends on the components you are using.
Dependency Walker is also a useful tool to find missing DLLs under Windows.
As for me it seems that something is missing. Qt on windows has the script windeployqt, it will provide all needed dependencies. See documentation http://doc.qt.io/qt-5/windows-deployment.html about use of this. On Windows you will be able to run cmd with loaded qt environment variables ( on Windows 7 see under windows applications menu - it will be available if qt is installed ). As Simon stated Dependency Walker is good tool.
I've been having troubles with the QCoreApplication::addLibraryPath(QString &Path) method on windows.
I've trying to use it to add directories where the application should be looking for dll that i'm loading dynamically with QLibrary.
I soon enough realized that it was not the right way to go. I now use a putenv approach to change directly my environement variables.
Plus, I still don't understand what exactly the addLibraryPath method is supposed to be used for?
I think qt documentation is not clear enough, regarding this topic.
There are (at least) 2 sorts of libs/dlls:
Essential Libs/Dlls das are already needed at program start (like Qt5core.dll).
"Functionality Libs" like the Qt Plugins and third party stuff, that can be loaded later.
It is not obvious (at least for me) which DLL is of sort 1 or sort 2. This leads to the problem that it may be nasty to find out which you can move into subfolders and point your application to it by addLibraryPath().
For me the following solution worked:
use windeploy to find out the bigger part of dependencies (my app's executable is in a "bin" folder below the project folder)
c:\Qt\Qt5.3.2\5.3\mingw482_32\bin\windeployqt.exe ..\bin\myapp.exe --release --force --compiler-runtime -libdir ..\bin -dir ..\bin\plugins
this puts the "sort 1" libs into the app folder
and the "sort 2" libs into a subfolder plugins
Additionally, it is needed to let the installer set an environment var "QT_PLUGIN_PATH" in registry to let the app find the plugins. I wasted hours just to find out that setting this path with addLibraryPath() at runtime is just not working. Also a qt.conf file seems not to work. The only alternative for me is setting a environment var in a .bat file, what is essentially the same like the registry setting.
Here's the registry key (in inno setup syntax):
Root: HKLM; Subkey: "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"; ValueType: string; ValueName: "QT_PLUGIN_PATH"; ValueData: "lib"
Another anoying thing is, that some libs are not identified by windeploy. These are mainly the compiler redistributables, that will vary with the compiler that you use. Others are more depending on the functions that you use, and somehow are not processed by windeploy. This fact is not documented obviously (at least I didn't see it) and is also not easy to understand. For my app, these are the following compiler redists and some database related libs:
libeay32.dll
libgcc_s_dw2-1.dll
libintl.dll
libpq.dll
libstdc++-6.dll
libwinpthread-1.dl
l
Dependency Walker is always said as a solution for finding this out. For me that didn't work either. Not all of the mentioned libs were listed, but the app isn't running without. Maybe it's because the libs are just loaded under special circumstances?
addLibraryPath adds a path to the ones that the application will search when dynamically loading libraries.
From the Qt documentation about QCoreApplication::​libraryPaths() :
This list will include the installation directory for plugins if it
exists (the default installation directory for plugins is
INSTALL/plugins, where INSTALL is the directory where Qt was
installed). The directory of the application executable (NOT the
working directory) is always added, as well as the colon separated
entries of the QT_PLUGIN_PATH environment variable.
Also it's stated in the Qt documentation that :
An application has an applicationDirPath() and an
applicationFilePath(). Library paths (see QLibrary) can be retrieved
with libraryPaths() and manipulated by setLibraryPaths(),
addLibraryPath(), and removeLibraryPath().
So it seems you can add the path for QLibrary with addLibraryPath.
I'm totally new in using Qt and I don't know a lot of stuff.
As a test I created a simple application using Visual Studio 2012 and Qt-VS-Add-in based on the newest Qt5.1
After I compiled the application it didn't work for me (gave errors), I searched all over the internet and found a lot of people saying that I have to copy those dlls mentioned below from the directory:
C:\Qt\Qt5.1.0\5.1.0\msvc2012\bin\
DLL's I had to copy to make my application work:
icudt51.dll
icuin51.dll
icuuc51.dll
libEGL.dll
libGLESv2.dll
Qt5Core.dll
Qt5Gui.dll
Qt5Widgets.dll
My problem is the size of these dlls, they're about "37 MB" and my application itself is only "30 KB"! So, those Qt libraries will add at least 37 MB to my application [ Which I don't see it happens with other Qt-based applications I download ]. Is there any solution can make me end up with a single small .exe file?!
And I heard some people saying that I have to also include a dll for Microsoft C++ Compiler, can you explain this for me?
Note: I've come across a lot of questions here on StackOverFlow but I couldn't find anything can help me, so please do not flag this as a duplication because if I found a clear answer I wouldn't post this question!
Any help would be appreciated.
UPDATE: Use windeployqt.exe! It works really well.
http://doc.qt.io/qt-5/windows-deployment.html#the-windows-deployment-tool
The simplest way to use windeployqt is to add the bin directory of
your Qt installation (e.g. ) to the PATH variable and then
run:
windeployqt <path-to-app-binary>
UPDATE: Upon Further testing, windeployqt did not copy over all the MingW dlls for me. (Tested with Qt 5.4 on Windows 10 with MingW 4.9.1). So you need to manually get the last 3 dlls before deploying:
libgcc_s_dw2-1.dll
libstdc++-6.dll
libwinpthread-1.dll
From
C:\Qt\5.4\mingw491_32\bin
I think you may have a few extras in your list... I would double check the docs in the links below...
Here is the definitive documentation on it:
http://doc.qt.io/qt-5/windows-deployment.html
http://doc.qt.io/qt-5/windows-deployment.html#application-dependencies
Size of Qt DLLs
The amazing Qt Libraries can do a lot, but they are kind of big. Some of the older versions of Qt might be a little smaller.
For Qt 4.8 msvc QtCore4.dll is 2.5 MB, and QtGui4.dll is 8.4 MB.
How Windows Resolves Shared Libraries/Dynamic Link Libraries (DLL)
Here is how Windows tracks down a library at runtime:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms682586(v=vs.85).aspx
Single Small EXE
If you statically link, then your EXE should grab the libraries it needs and gets built into a stand alone exe. It still may be dependent on msvc redistributables. See the next section for more info on it. But it now compiles down the .libs that you reference into your EXE and your exe no longer is pointing at other dynamically linked libraries. It does take more time to get your statically linked exe environment setup.
Your exe will certainly get bigger as it now includes the binary information for the libraries that you referenced before.
https://www.google.com/search?q=qt+static+linking
EDIT:
Statically building the exe, means that you aren't using the LGPL version.
means that you have to have your object files easy to access to end users if you are using LGPL.
I think #peppe described it well (see comment below):
Technically, you are allowed to statically link when using Qt under LGPL, even if your application is not using LGPL. The only tricky requirement is keeping the ability for a third party to relink your application against a different Qt version. But you can comply with that easily, f.i. by providing a huge object file (.o) of your application, that only needs to be linked against any Qt version.
http://blog.qt.io/blog/2009/11/30/qt-making-the-right-licensing-decision/
Look at the chart near the bottom. If you are doing the commercial version, then you can statically link, without worrying about the object files.
MSVC Redistributables
Redistributable dependencies have to do with the run-time library linker options.
http://msdn.microsoft.com/en-us/library/aa278396(v=vs.60).aspx
/MD, /ML, /MT, /LD (Use Run-Time Library)
To find these options in the development environment, click Settings on the Project menu. Then click the C/C++ tab, and click Code Generation in the Category box. See the Use Run-Time Library drop-down box.
These two links below talk about some older versions of visual studio, but the reasoning should still stand.
http://www.davidlenihan.com/2008/01/choosing_the_correct_cc_runtim.html
How do I make a fully statically linked .exe with Visual Studio Express 2005?
Hope that helps.
Just open your terminal execute your_qt_installpath/version/compiler/bin/windeployqt.exe YourApplication.exe. It will automatically copy all the required libs and stuff into the folder, where your exe is located and you can just distribute it.
For Windows you need to include qminimal.dll and qwindows.dll, you will have to put them in folder called platforms.
Even if you program is small you still call huge libraries to do the graphical interface. If the size is really important you should do a console project.
PS : You can check all the libraries you really need by opening your exe with the dependency walker.
I found another workaround without recompiling Qt again!
[ This solution may affect application execution time ]
First we need to use UPX to compress each one of Qt Libraries required by our application, they're often the dll's mentioned in the question. However, avoid compressing them too much because you'll notice that your application takes longer time to run.
[ Optional ]: If your application binary is large, you may find it useful to compress it using UPX.
After compressing all binaries, we want to get a single .exe file, so we can use
Enigma Virtual Box [ http://enigmaprotector.com/en/downloads.html ] to merge all .dll files with the main executable and we'll end up with a single tiny .exe file!
I'll just do it like this for now since I'm not able to recompile Qt with my own configurations on my current machine.
it looks to me that Qt5.2 requires fewer dll.
Qt5Core.dll
Qt5Gui.dll
Qt5Widgets.dll
in windows you also need "qwindows.dll" in folder "platforms".
give it a try.
A possibility for reducing the size of the DLLs is by compressing them with UPX as mentioned by Alaa Alrufaie. Another method is to wrap it into an installer (e.g. Inno Setup). The latter one is particularly useful if you want to distribute it to end users). I had a simple application requiring Qt5Core.dll, Qt5Gui.dll, Qt5Widgets.dll and qwindows.dll (in the folder "platforms") taking about 17 MB. After creating a setup file, it shrank to 5 MB.
When I run the program from IDE (VS2008) it works perfectly. When I want to launch it from Windows Commander it doesn't work because it needs DLL that wasn't found.
Used both debug and release builds.
Make sure the Qt DLL's are in your PATH. Two simple solutions are:
Copy Qt's DLL's to your EXE's directory.
Copy Qt's DLL's to %WINDOWS%\System32 (e.g. C:\WINDOWS\System32) (possibly unsafe, especially if you install another versions of Qt system-wide. Also, requires administrative privilages).
You should make sure that the DLLs needed by the executable (probably QT Dlls) are in the PATH or in the same directory as the executable. You can find which dlls are needed by using depends.exe
another solution would be to place path to qt bin subdir in VS tools->options->projects and solutions->VC++ directories.
You could link it statically with all the libraries it needs. Saves messing around with DLLs and stuff. On the down side, you can't update DLLs on your installed PCs to get updated/improved/fixed functionality, and will need to rebuild and redeploy.
So whether or not this is viable depends on what your installation targets are - a few PCs controlled by you, or every man+dog who decides to download your program?
Statically compiling in a library bug (security hole for example) and shipping that to your clients would be very poor form. Doing the same on a secure corporate intranet may make it worth doing just so that you know that each install is running exactly the same.