Building QT module from source - qt

Can please someone explain in detail how to build a single qt module. I tried to understand the build sources documentation, but there is no info on how to build just a single module, let alone what to do with it after. I would like to do some modification on the qtmultimedia module, build it with the changes and use that module in my existing QT installation. I need only the IOS part.

Use the qmake executable from the Qt build you want to build with to create a Makefile. Then run make.
<path_to_qt_build>/bin/qmake <path_to_module>
make [or nmake or jom for windows]

After configuring process just put:
make -j<N> module-<foo>,
where "foo" is a module's name you are desired of

Related

CMake doesn't find Qt5QuickCompiler

I'm trying to build a Qt Quick Controls application with CMake. I use the following documentation:
http://doc.qt.io/QtQuickCompiler/qquickcompiler-building-with-cmake.html
When running CMake, I'm getting this error:
By not providing "FindQt5QuickCompiler.cmake" in CMAKE_MODULE_PATH this
project has asked CMake to find a package configuration file provided by
"Qt5QuickCompiler", but CMake did not find one.
Could not find a package configuration file provided by "Qt5QuickCompiler"
with any of the following names:
Qt5QuickCompilerConfig.cmake
qt5quickcompiler-config.cmake
at this line:
FIND_PACKAGE(Qt5QuickCompiler)
Obviously CMake doesn't find Qt5QuickCompiler. I checked in my Qt folder (C:\Qt) but it's not there. Yet I could run this application with QMake.
What do I need to set in order to find Qt5QuickCompiler?
I just stumbled upon the same issue with Qt 5.12 under Linux. The documentation under https://doc.qt.io/QtQuickCompiler/qquickcompiler-building-with-cmake.html currently seems to be wrong.
Use QuickCompiler after COMPONENTS in the Qt5 find_package instead of trying to add it via find_package(Qt5QuickCompiler). Adapting the example from the link, use
find_package(Qt5 COMPONENTS Quick Core Network QuickCompiler)
qtquick_compiler_add_resources(RESOURCES example.qrc)
add_executable(myapp ${SRC_LIST} ${RESOURCES)
instead of
find_package(Qt5 COMPONENTS Quick Core Network)
find_package(Qt5QuickCompiler)
qtquick_compiler_add_resources(RESOURCES example.qrc)
add_executable(myapp ${SRC_LIST} ${RESOURCES)
The error is pretty clear: CMake doesn't have a module for the Qt5QuickCompiler to find it. It just doesn't know what it is. I've just checked the corresponding cmake folder and it doesn't have that file. I'm not sure what that Qt documentation page is talking about but there is no such a file in the CMake distribution. Maybe Qt sources have this file somewhere?
You need to build Qt5 with Qt Quick compiler which you can download from http://www.qt.io/qt-quick/. In the build directory of Qt Quick compiler, you will find Qt5QuickCompilerConfig.cmake.
Copy the path to this directory, and add to CMAKE_PREFIX_PATH like this
cmake -DCMAKE_PRFEIX_PATH=<pathToFile> <pathToSrcDirOfYourProject>

How to force qtcreator use qbs profile?

I'm working with qtcreator 3.5.0 and custom build of QT 5.5.0
I want to build my project both with qbs & qtcreator.
So, I've created qbs profile, as described in qbs manual, and it works well. But I've failed to force qtcreator use this profile. It creates it's own profile, based on mine, but with different name.
e.g. `qtc_Desktop-debug` & `qtc_Desktop_0aa29aa9-debug`
The problem is that build paths includes profile names. And even if I have completed build by qbs, I need to build all the sources again from qtcreator, if I want to use it.
To copy exactly build done by QtCreator just copy command displayed in project configuration details (to make thinks easier you probably want to wrap it in script file):
BTW: QtCreator's QBS profiles are direct copies of your build Kits configuration (set in Tools > Options > Build & Run > Kits) so if you need to tune it you should do it there.

Using Qt Installer Framework to create my Application Installer

I want to create an installer for my Application. So, I have read about Qt Installer Framework and I tested the tutorial example and create the installer and everything work find with the example. But I have a doubt when I try to do the same process for my Application. When I compile the code a folder is created at the same level of my code:
MyApplication (my code)
build-MyApplication-Desktop_Qt_5_4_1_MinGW_32bit-Release (code compiled)
So my questions are:
What files of the compilation do I need to copy into the folder myinstaller/packages/vendor/ recommended by Qt Intaller Framework?
If I have dependencies of Qt like serialport, multimedia, and others, how do I insert these dependecies with Qt Installer Framework?
windeployqt.exe is what you want. Just run that on the command line and give it your executable as the argument. It will automatically copy in all the required Qt libraries and even provide the runtime redistributable installer. Then you can use the binarycreator to generate an installer.
You can put all the dependencies in myinstaller/packages/vendor/data, along with your exe. and eventual additional files. I recommended using i.e. dependency walker for finding all the required dependencies. Some of the binarycreator tutorials on qt are outdated; make sure you use the command
<location-of-ifw>\binarycreator.exe -t <location-of-ifw>\installerbase.exe -p <package_directory> -c <config_directory>\<config_file> <installer_name>
with the appropriate arguments.

Forcing specific version of QT in .pro file

I'm searching for a way to force a specific version of QT in a .pro file. To be more specific, I'd like to force qmake to use only QT 5.x version with my project instead of QT 4.x and QT 5.x
Is there a way to do so?
PS: I'm not asking for a way to stop/halt the compile process (aka check QT version, and if lower than 5.x just throw qFatal/equivalent). I'm looking for a way to actually choose which version to use while generating the Makefile with qmake
You can throw a error if a user is running qmake with a version you do not want him to use. ex:
lessThan(QT_MAJOR_VERSION, 5): error("requires Qt 5")
I really doubt you can do this. qmake is a part of framework and goes together with libraries. When you say Qt of specific verion you mean only libraries, but it is not correct.
To use specific version of Qt, you actially need to run different version of qmake. If you are using QtCreator - you should select it in project's options, if not - type absolute path to file qmake. You can find out, which version of Qt qmake uses, you can type qmake --version.
As Amartel wrote in his answer, you should point to the correct qmake version (check it by typing qmake --version in the console)
It might be that your project has been generated using the wrong qmake executable and some files are not removed even if you issue a nmake clean or make clean.
Check that there are no Makefile in the source tree after the clean (these files will typically contain the path to the qt version to use, and if not regenerated correctly will point to the wrong Qt version).

Compiling Qt project in a directory outside of the install directory

I've been working on a project using OpenCV for a while, and am ready to upgrade my user interface from using cvWaitKey() to get key presses and emulating buttons with trackbars. Ha. So I've decided to use Qt.
I'd like to continue developing in the same directory I've been using, which is, of course, outside of the Qt install directory, C:\Qt\2010.05\qt. Using the "Qt Command Prompt", I'm able to compile the Hello Notepad example in directories both in and out of C:\Qt\2010.05\qt, namely C:\Qt\2010.05\qt\abc and C:\Qt\2010.05\abc.
However, while compiling under C:\ ... \qt produces executables in both the debug and release directories, compiling outside of it only produces the debug executable, along with a .o file (object code?). I did some comparisons using WinMerge, and found that the following lines (among others) differ in the two makefiles (generated using qmake -project and then qmake):
Inside qt\
first: all
install: debug-install release-install
uninstall: debug-uninstall release-uninstall
Outside qt\
first: debug
install: debug-install
uninstall: debug-uninstall
That's clearly the problem (the .pro files generated by qmake -project differ only in timestamp). I'm sure there's an easy answer out there to what's causing this... I hope there's an easy answer to how I can work around it. Also, I intend to use QtCreator some; hopefully the solution is the same for the IDE as the Command-Line compiler.
Thanks!
Nolan
p.s.: I don't think this is the same issue: Qmake does not support build directories below the source directory ...in any case, I'm not sure I understand the answer.
You should be able to add
CONFIG += release
to your .pro file, to build for release target. There's also
CONFIG += debug_and_release
iirc.
QtCreator has a GUI element for toggling between build targets, you might try opening the .pro with that application if you find you need to switch back and forth often.

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