Use a LLVM compiled version of Qt - qt

I've seen some mkspec for mac or linux using llvm.
Does anyone use an llvm compiled version of Qt ? Or llvm on their Qt Projects ? does it speed up compilation times ? Is your project faster ?

According to this bug compiling Qt using LLVM is not yet possible.

This is not true - Qt can be compiled via llvm-gcc since version 1.9. clang is currently "almost" able to compile Qt fully. Note that the code of Qt is not sometimes standard-compliant :)

Related

Unknown module(s) in QT: declarative

Sorry, this may be a dumb question, but I'm totally new in QT, I just need to run a project and Log some data.
I installed Qt "qt-unified-windows-x86-2.0.3-2-online", open the project and then click on configure, and then I got this error:
Unknown module(s) in QT: declarative
which wont let me compile the code. Everything else looks fine.
From researching I get that I may lack some libraries, I'm using windows, How do I get the proper library in windows? which is the library I need?
I'm using "Qt Creator user the kit Desktop Qt 5.7.0 MinGW 32bit."
Thank you.
I'm downloading linux, a live version, to try to run the code in there
The error occurs when trying to build a project that depends on the deprecated QtDeclarative module on Qt version 5.6 and later, as the module was removed in version 5.6.
The source code for the module is still available you can compile it from source. Or you can install a Qt version below Qt 5.6 to build the project.
You probably don't have declarative library installed somehow, here it is recommended to use a command-line utility named windeployqt, something like
windeployqt -declarative

Qt Creator - setting up a kit with a cross-compiler

I'm attempting to use Qt creator to cross-compile a project, but have an issue matching the Qt version and my specified compiler toolchain.
I have created a Kit setting up a Device, selecting my toolchain as the compiler (GCC ARM Linux in this case), but I only have a locally installed system Qt (5.0.2 on Mint x86).
Qt Creator understandably tells me the compiler cannot produce code for the Qt version; all the guides I have found suggest using a Qt compiled for the target platform. This doesn't make sense though - it attempts to run qmake compiled for a different architecture and fails
How do I install or configure/compile a Qt version to work with the cross compiler? Maybe I can modify my existing one to understand this setup?
Thanks
This makes absolutely sense. The advice to use a Qt, which is compiled for your target platform is correct. But this does not mean that you use a Qt that was compiled natively on that target platform. You need to use a Qt, which was compiled with a special cross compiler on your host platform for your target platform. This way qmake and other build tools remain executable on your host, but create configurations for your target.
So, if you have a compiler, which can create ARM code, use it to build your Qt. Then you can create a kit in QtCreator out of this compiler/Qt pair.
Greenflow is right. I would like to add some information. I have cross compiled Qt 5.4.1 on Windows having an ARM Linux as target platform. You just need to configure the build properly. Here's what I did:
./configure -platform win32-g++ -xplatform linux-arm-gnueabihf-g++ .....
So Qt tools (qmake,moc,etc...) were built as Windows binaries and all the libraries were built as Linux binaries. Check for the available platforms in qtbase/mkspecs.

Compiling and linking library MSVC/MingW

I'm a big fan of StackOverflow because you always have answers for problems, and now is my chance to get advance of it Ö!
I'm trying to use a library which I got in the Internet, its OZCollide. Its suppossed to be crossplatform as it says in its website "Cross-platform, works on Windows, Linux and Macintosh, in fact any platform supporting VisualStudio 6/7 or gcc"
I got all the .h and .cpp, compile them with MinGW as objects (.o) and then link them all using ar. But the problem is when I include and use the library on my project (QT & MinGW) it throws "undefined reference".
I thought the problem could be that library examples only uses Visual Studio, so the library coulnd't be compiled for MinGW, but the website tells other story.
Thanks for your time!
EDIT: Okay I have managed to compile it and use it moving to another computer and compiling makefile. The only one difference is that Computer A had Cygwing and MinGW installed (with Cygwin set up in Windows path) and Computer B only had MinGW.
So I guess the problem was Makefile calling for g++ and Cygwin g++ got called instead of MinGW g++??
If I'm right, whats the difference between Cygwin and MinGW?
if you have experience with CMake, create your own CMakeLists file and import/link this libraries against your project. In this way, you can create projects for MinGW/MSVC/Linux/etc.
Here you'll find a good start with CMake http://www.cmake.org/cmake-tutorial/

Integrating QWT 6.0.1 with Qt Creator/Designer 4.8.0

I've installed the Qt SDK version 4.8.0 (to C:\QtSDK) on a Windows 7 64-bit machine. I've also installed and successfully compiled QWT 6.0.1 with MSVC2010.
I can use QWT in C++ code by linking to the libraries; however when I try to use the plugin I get an error that I can't seem to find on the Googles.
My failed plugin error is:
The plugin 'C:/QtSDK/QtCreator/bin/designer/qwt_designer_plugin.dll' uses an incompatible Qt library. (4.8.0) [release]
My QWTbuild.pri has CONFIG += debug_and_release
I built the plugin by doing:
C:\QtSDK\QWT\qwt-6.0.1\designer > qmake designer.pro
C:\QtSDK\QWT\qwt-6.0.1\designer > nmake release
I then copied the .dll generated (qwt_designer_plugin.dll) in C:\QtSDK\QWT\qwt-6.0.1\designer\plugins\designer to my plugin path for QtCreator (C:\QtSDK\QtCreator\bin\designer)
I've also put the .dll and the .lib generated in the Qt plugins folder (C:\QtSDK\Desktop\Qt\4.8.0\msvc2010\plugins\designer).
I've also linked my libraries in the project file containing the form I'm trying to build.
I'm sure that there's something small I'm missing, but I can't seem to find it. What am I doing wrong here? Any help would be greatly appreciated.
Regards,
Alexis
The Qt plugins should use the same version of Qt or a lower version with the same major number as the application they are loaded in.
Since the Qt Creator currently included in the Qt SDK seems to use Qt 4.7.4, you should probably recompile Qwt for that version of Qt.

Cross-Compiling Qt Applications from Windows to Mac OS

Can anyone tell me how to build .app extension files through Qt Creator-SDK and MingW? GCC Compiler is also installed.
I have done is
qmake -spec macx-xcode project_name.pro
It created supporting files to create .app extension (when opened in Notepad).
Thank You.
I recommend CMake: it does what it says on the tin: cross-platform make. Integrates nicely with Qt (it's what KDE uses).

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