I would like to know if it is possible to create a Qt application that uses the qt5 version of core library and the qt4 version of the gui library. I would like to use some features available only in qt5, like the QCommandLineParser class, but it is not possible for me to use qt5gui, only the qt4 version is working.
No that's not possible, you can't link an application with mixed versions of Qt, actually you can't even compile it.. if you need something very specific you can extract from the code, but you need a commercial license for this.
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I am setting up a Qt project which will be cross-copiled for a given display (running on ARM/Linux). The display will come with a self-contained cross-build toolchain which comprises Qt libraries with a specific Qt version (probably 5.15).
Now I would like to use a specific "static" toolchain incl. Qt libraries to also generate x86-builds of this Qt project (for testing, simulation; building/running on Linux and maybe also on Windows).
I'd avoid using the GCC and Qt development files introduced by the Linux package manager (e.g. apt), because the are not tied to a specific Qt version, i.e. upgrading the OS would always come with the risk to introduce build problems or break compatibility completely.
Are there good-practice approaches to achieve this?
So far I see three options:
Use a docker image
Possible problems:
Finding a image with the correct Qt version
building the Qt application would then work, but to execute it, the compatible Qt LGPL shared libs need to be available to the Qt application binary
Use a x86 -> x86 "standalone" toolchain
Find some standalone x86-toolchain analog to those (x86 -> x86), but additionaly...
it would either have to come with the Qt development files in the correct version
or we would have to build the Qt sources with this toolchain, and then extend the toolchain with the Qt built artifacts
Would be the preferred solution (and currently seems to be the most feasible of the approaches I can think of).
Virtual machine
Possible problems:
Finding a OS version with the correct Qt version
Select a OS version that contains the correct Qt version via package manager.
Not very elegant.
Qt online installer
only provides a limited choice of Qt versions (as of today: 5.15.2, 6.2.4, 6.3.2, 6.4.0) which is probably subject to change in the future
I need to move my code from a C++/OpenGL and Config.txt situation to a UI friendly space. I was told here to try Qt and installed it in Windows.
The issue I ran into is that it did not support the OpenGL version I needed out of the box and I had to rebuild with the -opengl desktop parameter.
First time doing this, but was able to follow the instructions (and a ton of Google) and it "succesfully" was built. My issue now is I am unsure how to make the files I have work with Qt Creator.
I copied over all the folders from the qt5 folder created by git over to the Src folder in Qt5.0.1/5.0.1/Src but the hellogl example still wouldn't build.
I checked the options and it was pointing to a qmake in Qt5.0.1/5.0.1/msvc2010/bin so I copied over the qmake.exe from qtbase/qmake over to this folder (renaming the old one) and now Qt Creator builds the hellogl example on my Windows system.
My worry is, did I do this the right way? I fumbled around and got something, but is this the way I should have proceeded after I built the qt5 from git? If not what was the way I should have gone about making it all work with the Qt Creator?
The typical way to utilize the modern OpenGL the feature set (post fixed-function pipeline) in Qt is by utilizing a extension wrangler (GLEW) that finds all the OpenGL functions your graphics drivers support BEFORE Qt includes any OpenGL headers.
To accomplish this simply do the following:
If you already haven't, download GLEW (or another extension wrangler if you wish) and install it in your system path. I would recommend the 32 bit package as it will be easier to work with.
#include glew.h in your source code before any other Qt header includes that may use OpenGL headers. Just to be safe, make glew.h the first header included in your source code.
In your Qt project's .pro file add the line LIBS += -lGLEW (mac/linux) or LIBS += -lglew32 (windows).
Note: Beware of using Qt OpenGL wrappers when implementing an application that uses post fixed-function pipeline facilities. Qt 5's OpenGL wrappers all operate using the OpenGL ES 2.0 specification which may cause problems when interleaved with your OpenGL 3/4 code. Even QPainter can become troublesome when performing overpainting on a QGLWidget due to it's heavy use of the fixed-function transformation stack. I am currently developing a library called QGLX that provides alternative Qt wrappers designed for complying to the modern desktop OpenGL specification. The beta will hopefully be released by the end of this year for Qt 4 & Qt 5.
I need to port one of my old program to Windows. The current version uses Qt 3 on Linux.
I'd like to see it within few days only to do some tests.
Instead of porting my code on Qt 4 (no time now), is it possible to recompile on Windows with Qt 3? Do I also need minGW? Which problems may I have doing this porting?
I can't find Qt 3 for windows, can someone give me a link? or I can use the same qt source I use on Linux?
Yes, you can !
Download the qt-win-3.3.x-8 project on Sourceforge.
QT4 still has back-compatible QT3 classes, prefixed with Q3* (see http://qt-project.org/doc/qt-4.8/qt3support.html)
You should be able to compile & run you QT3 app on QT4 via those classes with minimal adaptations.
Qt-3.2 for Windows was also distributed in a CD bundled with the book "C++ GUI programming with Qt3" at no additional cost with a license for non-commercial use.
ISBN: 978-0131240728
The supported compilers were MSVC and Borland. MingW is not mentioned.
I am developing an application in Qt, but using D language (with QtD binding). I've noticed that my app crashes with Qt 4.7.x, so I need to use Qt 4.6.2 instead. However in my system Qt 4.7.2 is installed. Unfortunately I neither make QtD work with the latest Qt versions nor (I'm afraid) count on QtD developers...
The only thing I need to make my application install in system Qt 4.6.2 libs and use it, but let all the other applications still use Qt 4.7.2. Is it possible? If it is, how to do it then?
The answer to your question is the version of Qt is determined by the qmake you use to generate your Makefile.
/opt/QtSDK/Qt-4.6.2/bin/qmake
/opt/QtSDK/Qt-4.7.3/bin/qmake
Each will use the library in the directory.
It is possible to install several versions of the library into one system, and all package managers (rpm, deb) support this out of the box.
These libraries will be just differently named. For example, if id do
ls /usr/lib/ | grep libcurl
on my system, I'll get:
libcurl-gnutls.so.3
libcurl-gnutls.so.4
libcurl-gnutls.so.4.2.0
libcurl.so.3
libcurl.so.4
libcurl.so.4.2.0
, so, different version of the same library happily live together.
All you need to do is to link against the desired version of QT library. You need to sepcify it in linker options (don't remember the exact option).
Is there a quick, straightforward way to make a Qt application into an executable? I attempted to follow the instructions at http://doc.qt.digia.com/4.1/deployment-windows.html but have been unsuccesfull thus far; I'm unable to Any help would be much appreciated. Thanks!
I always use CMake to build Qt projects, it's easy, free and cross platform. Guide : Compiling Qt4 apps with CMake. CMake also come with CPack to easly make installer for Windows, Mac and Linux.
I agree with chmod700 about the Qt Creator suggestion, it's not my favorite IDE but it's still really nice and easy.
Do you mean an installer package? I assume you are able to compile, link, and run your app and you mean how do you package it up for others.
http://installbuilder.bitrock.com/ <-- special handling of Qt based projects but costs $
http://www.jrsoftware.org/isinfo.php <-- my personal favorite and it's free (can be rough to learn advanced features though)
Though if you mean how do you build your app, you may want to try the new Qt Creator (http://www.qtsoftware.com/products/appdev/developer-tools/developer-tools#qt-tools-at-a) which will setup build targets for you and really makes desktop Qt dev a snap. Also if you're still using 4.1, you can now use 4.5 under the LGPL on all platforms making it almost a no-brainer to upgrade.
I'm not sure if I understand your problem. Assuming you're using MinGW, it's really easy and quite straightforward:
get the Qt sources and unpack them to some folder (f.e. c:\Qt\4.5.0-static)
install MinGW. Make sure the MinGW executable folder is in the %PATH% variable.
open a cmd windows, go to the Qt sources and run configure -static. You can add other config options if you like to, but usually you don't need that.
when building Qt finished, go to your application sources, open a cmd window and run the qmake of your built Qt installation -- i.e. c:\Qt\4.5.0-static\bin\qmake in the example given above.
run make
you get a statically linked binary in the end (you might want to check it with Dependency Walker).
Doing the same using Visual Studio is pretty similar.
Or do you want to build dynamically and create an installer package?