C++, Qt - How do I get rid of dll dependencies? - c++

I have compiled my Qt application and now have the following question - now my built project requires QtCore4.dll and QtGui4.dll to be located at the same folder where the .exe file is. (I built my project using MSVS2008 with Qt addon)
Q:
Is there any way to combine my final application with these .dll files so that they make one large .exe-file? (I simply don't want to have another bunch of dll files with my release - app)
Thank you.

You need to build and link to Qt statically.
Edit: Here's an updated link to at least similar information.

Bundle them into a self-extracting .exe (e.g. using 7zip) which extracts all files to a temporary directory, runs the program, then deletes the files after the program exits.
This will be easier, less time consuming and less legally constraining than statically linking Qt as previously suggested.

Of course you could statically link someway. But the point of using DLL should be to make program smaller (both on disk and in memory, if other apps are using Qt libs of course)... DLL such as those should be systemwide so that other apps needing them can use them. Basically you have to say to people wanting your program to work, to install the Qt framework.
Deploying the other way is explained here, read the part related to Static Linking.

Related

C++ qt application compilation in one file

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

Can two independent Qt applications use same DLL files?

I'm having a difficult problem to solve. I'm having two Qt-based applications, first one is in the main folder and the second one is located in it's subdirectory (yes, I'm forced to have it this way). The issue I'm facing is that I have to deliver 5 exact the same DLL's files for each application. I wouldn't have problem with that, if they wouldn't weight so much (10 DLL files = 60~ MB). Which is, definately too much.
On my debug build I am able to set the PATH variable within Visual Studio settings, and I will be not able to do so on production machines.
Is there any way I could set one of those application to rely on DLL files located in subdirectory?
I don't know what kind of an installer you're using, but the dlls should be stored only once in the archive, and the files should be hard linked on installation. So it's a non-issue unless your installer is broken or the install script is.

How to run a Qt executable file dependent on .dll files?

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.

How to Package all the libraries and dependencies in a C++ Project? [duplicate]

This question already has answers here:
Deploying Qt 5 App on Windows
(2 answers)
Closed 8 years ago.
I am working with C++ for a project and using the Qt framework to help me out. However, I am dealing with some annoying issues and I hope someone can help me out here. Here's what I have so far"
I created my C++ application using Qt
Compiled my application and send out the final .exe file
I also installed a separate non-developmental OS to test my application. On the test OS I just had to install the Qt libraries and my application would run just fine.
But some of the users of my application are having trouble running the application. Some of them installed Qt but the application still cannot find the required .dll files or if they installed Qt fine the application still fails because Qt itself has some other dependency. Or they are on a 64 bit but my application is 32-bit... so their 64 bit Qt library does not work with my application.
So, what I am thinking of doing is basically get a tree of all the .dll files my application will need to run smoothly and include all of them as part of my .exe application.
Certainly the file size will increase but at least I will have the peace of mind knowing that the application has everything it needs.
I am reading more about Static/Dynamic Linking etc... but in the C++ world it is a bit different. Is there a system in C++ that is similar to Java where you specify the libraries and during compilation C++ would copy the necessary libraries to the end product?
dependency walker will show you all needed DLLs you need to pass them along as well
people generally use a packager for this, with which you can also set up environment variables and fiddle with the registry
You should place Qt DLLs along the release version of your executable. These are QtCore4.dll, QtGui4.dll (Qt5Core.dll, Qt5Gui.dll,... for Qt5) and possibly the ones for other modules that you have used. These dll files are in your installed Qt Directory in bin folder.
You should also place msvcr100.dll and msvcp100.dll in case you are using MSVS2010.
If you are using plugins you should place their dll in a folder named "plugins" beside youe exe. In case of using icons and images you should ship their dlls like qico4.dll and qsvg4.dll (qico.dll and qsvg.dll for Qt5) in a folder named "imageformats".

Do I have to include all these Qt dlls with my application?

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.