Qt example project fails to build (No CMake configuration found) - cmake

I am trying to simply open Qt6.4.1 sensors example project, but it says that no CMake configuration found. I already made some simple Qt6 applications for Windows, and i have entire Qt6.4.1 package installed, so cant blame on bad installation. There is an error on line find_package(Qt6 REQUIRED COMPONENTS Core Gui Quick Sensors Svg) in CMakeLists.txt. Full error message:
C:\Qt\Examples\Qt-6.4.1\sensors\sensorsshowcase\CMakeLists.txt:12: error: By not providing "FindQt6.cmake" in CMAKE_MODULE_PATH this project has asked CMake to find a package configuration file provided by "Qt6", but CMake did not find one. Could not find a package configuration file provided by "Qt6" with any of the following names: Qt6Config.cmake qt6-config.cmake Add the installation prefix of "Qt6" to CMAKE_PREFIX_PATH or set "Qt6_DIR" to a directory containing one of the above files. If "Qt6" provides a separate development package or SDK, be sure it has been installed.

Pass the path to the directory containing the Qt6 files via CMAKE_PREFIX_PATH cache variable during configuration.
Note: Make sure to specify the type of the variable as PATH or use forward slashes as path separator for this to work properly.
E.g. for me I'd need to pass
-D CMAKE_PREFIX_PATH=D:/Qt/6.4.1/msvc2019_64
to tell CMake to look into the directory containing the Qt6.4.1 files compiled with MSVC.
Make sure that the directory you pass contains the file lib/cmake/Qt6/Qt6Config.cmake; this is the file find_package(Qt6 REQUIRED COMPONENTS ...) is looking for.
You can also fix your project setup that previously failed by adding the cache variable.
cmake -D CMAKE_PREFIX_PATH=D:/Qt/6.4.1/msvc2019_64 path/to/build_dir
Note: Don't forget to add the -A ... option when configuring a VS project; CMake defaults to Win32 as architecture, at least on my system.
You could add this info to a CMAKE_PREFIX_PATH environment variable, if you don't want to specify the info cache variable for every single project using qt 6 that you want to set up on your machine.

Related

I tried to build something, but this error came and I couldn't get SW also

By not providing "FindSW.cmake" in CMAKE_MODULE_PATH this project has asked
CMake to find a package configuration file provided by "SW", but CMake did
not find one.
Could not find a package configuration file provided by "SW" with any of
the following names:
SWConfig.cmake
sw-config.cmake
Add the installation prefix of "SW" to CMAKE_PREFIX_PATH or set "SW_DIR" to
a directory containing one of the above files. If "SW" provides a separate
development package or SDK, be sure it has been installed.
What I am trying to build is leptonica, but I can't do it without having there .cmake files, and I have no idea how I can get them, since I couldn't build SW.

cmake not finding package configuration file

I am using Qt Creator as IDE and MSVC 2019.
I built and installed the pagmo library from the source. Now I am trying to use it for my project.
Even though the installation seems fine, when I try to load it I get strange errors, telling me that "pagmo" is not found. In particular:
error:
By not providing "FindPagmo.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Pagmo",
but CMake did not find one.
Could not find a package configuration file provided by "Pagmo" with any
of the following names:
PagmoConfig.cmake
pagmo-config.cmake
Add the installation prefix of "Pagmo" to CMAKE_PREFIX_PATH or set
"Pagmo_DIR" to a directory containing one of the above files. If
"Pagmo" provides a separate development package or SDK, be sure it has
been installed.
In my CMakeLists.txt I have set the following command:
find_package(Pagmo REQUIRED)
Now, as far as I know FindPagmo.cmake does not exist, BUT I am giving as input parameter Pagmo_DIR, which contains the file pagmo-config.cmake. I can't understand why CMake is not finding it. I also tried to set CMAKE_MODULE_PATH to the same folder but nothing changed.
Does anybody have suggestions on how to solve this problem?
I am setting pagmo directory as follows:
-DPagmo_DIR = C:\Lib\pagmo\install\debug\lib\cmake\pagmo
in that folder I have the following files:
Findpagmo_IPOPT.cmake;
pagmo_export.cmake;
pagmo_export-debug.cmake;
pagmo-config.cmake;
pagmo-config-version.cmake;
PagmoFindBoost.cmake

How to perform the "make install" step after building aws-sdk-cpp using Qt Creator and CMake

I am trying to add aws-sdk-cpp as a submodule in my Qt application using Qt Creator and CMake. I want it to build for any platform without doing the building and installing on the command line as described here.
My project structure and CMakeLists.txt files looks like this:
I have successfully built the entire aws-sdk-cpp using MSVC2019 in debug mode using Qt Creator. My projects build folder is now 15 GB containing all the built libraries. The current issue I'm now facing is this error:
CMake Error at app/CMakeLists.txt:23 (find_package):
By not providing "FindAWSSDK.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "AWSSDK", but
CMake did not find one.
Could not find a package configuration file provided by "AWSSDK" with any
of the following names:
AWSSDKConfig.cmake
awssdk-config.cmake
Add the installation prefix of "AWSSDK" to CMAKE_PREFIX_PATH or set
"AWSSDK_DIR" to a directory containing one of the above files. If "AWSSDK"
provides a separate development package or SDK, be sure it has been
installed.
I think what is missing is the make install step described here and to set the path to AWSSDK_DIR.
I'm very new to CMake and I have not found any way to perform the make install step in the CMakeLists.txt file and then be able to set the AWSSDK_DIR which points to the AWSSDKConfig.cmake or awssdk-config.cmake file missing.
I'm also not sure which CMakeLists.txt file this should be written or if there is an entire other way to do this? Currently I'm stuck getting nowhere..

Best practices with CMake with non-standard include and library directories

I have been trying to build Mozilla RR on a Linux box at work using CMake. We have a slightly eccentric arrangement where shared libraries are stored on network drives in locations like /sw/external/product-name/linux64_g63.dll/. Further, I have built some dependencies for the project in $HOME/sw/. (I am not a sudoer on this box.)
I am rather baffled as how I am supposed to communicate to CMake to look in non-standard directories. So far I have fudged:
PKG_CONFIG_PATH=$HOME/sw/capnproto-0.6.1/lib/pkconfig \
CC=gcc-6.3 CXX=g++-6.3 \
cmake \
-DCMAKE_INSTALL_PREFIX=$HOME/sw/rr-5.1.0 \
-DPYTHON_EXECUTABLE=$HOME/bin/python2 \
-DCMAKE_FIND_ROOT_PATH=$HOME/sw/libseccomp-2.2.3/ \
../src/
Which is obviously not a scalable solution, but it does at least complete the configuration successfully and emit some Makefiles.
If I omit -DCMAKE_FIND_ROOT_PATH=$HOME/sw/libseccomp-2.2.3/, CMake fails, complaining about a missing libseccomp-2.2.3 dependency. But it works if I do have that definition, telling me that CMake understands where the libseccomp-2.2.3 files are and so will properly add the paths to the necessary compiler invocations.
However, make does not succeed, because gcc fails to find a required header file from the libseccomp probject. Examining make VERBOSE=1, I find that CMake hasn't added -I$HOME/sw/libseccomp-2.2.3/include to the gcc invocation.
I feel like this is not the right approach. The other answers I have looked at tell me to modify the CMakeLists.txt file, but surely
that is not going to be scalable across multiple CMake projects, and
for each project, that will need me to maintain a separate CMakeLists.txt file for every platform (Solaris/Linux/Darwin/Cygwin) I build the software on.
Is there a canonical solution to solving this problem? Perhaps a per-site configuration file that will tell CMake how to find libraries and headers, for all projects I build on that site?
Your approach is correct, but cmake is never told to include SECCOMP - see end of this post.
The way cmake can be informed about custom dependency directory depends on how the dependency is searched (i.e. on what is written in CMakeLists.txt).
find_package/find_library/find_path/find_program
If dependency is found with one of above-mentioned commands, custom search directories can be easily added with CMAKE_PREFIX_PATH. There is no need to add full path to include, lib or bin - when package root is added find_-command will check appropriate sub-directories. CMAKE_PREFIX_PATH can be also set with environment variable.
Second option is CMAKE_FIND_ROOT_PATH. Every path added to CMAKE_FIND_ROOT_PATH list treated as separate root directory and is searched before system root directory.
Note that CMAKE_FIND_ROOT_PATH will be ignored by find_-commands with NO_CMAKE_FIND_ROOT_PATH argument.
Following four variables may be used to tune the usage of CMAKE_FIND_ROOT_PATH:
CMAKE_FIND_ROOT_PATH_MODE_PACKAGE
CMAKE_FIND_ROOT_PATH_MODE_INCLUDE
CMAKE_FIND_ROOT_PATH_MODE_LIBRARY
CMAKE_FIND_ROOT_PATH_MODE_PROGRAM
When use of host system default libraries is undesired setting CMAKE_FIND_ROOT_PATH_MODE_INCLUDE and CMAKE_FIND_ROOT_PATH_MODE_LIBRARY to ONLY is a good practice. If dependency library or header is not found in CMAKE_FIND_ROOT_PATH the configuration will fail. If cmake is allowed search system paths too, it is most likely that errors will occur during linking step or even runtime.
See find_package docs for more details.
find_package only
All above applies to find_package command too.
find_package can operate in two modes MODULE and CONFIG.
In MODULE mode cmake uses Find[PackageName].cmake script (module) to find dependent package. CMake comes with large number of modules and custom modules can be added with CMAKE_MODULE_PATH variable. Often find-modules can be informed about custom search paths via environment or cmake variables.
E.g. FindGTest.cmake searches path stored in GTEST_ROOT variable.
If no find module is available, find_package enters CONFIG mode. If a dependency package provides [PackageName]Config.cmake or [LowercasePackageName]-config.cmake cmake can be easily informed about that package with [PackageName]_DIR variable.
Example:
CMakeLists.txt contains:
find_package(Qt5)
FindQt5.cmake is not available, but ~/Qt5/Qt5.8/lib/cmake/Qt5Config.cmake file exists, so add
-DQt5_DIR="${HOME}/Qt5/Qt5.8/lib/cmake"
to cmake call.
pkg-config
CMake can use information provided by external pkg-config tool. It is usually done with pkg_check_modules command. Directory used by pkg-config can be customized with PKG_CONFIG_PATH environment variable. According to cmake documentation instead of setting PKG_CONFIG_PATH, custom .pc-files directories can be added via CMAKE_PREFIX_PATH. If CMake version is pre-3.1, PKG_CONFIG_USE_CMAKE_PREFIX_PATH have to be set to TRUE(ON) to enable this feature.
Methods of customizing dependencies search path is defined by CMakeLists.txt content. There is no universal solution here.
And now back to missing SECCOMP headers...
In CMakeLists.txt SECCOMP header is found with
find_path(SECCOMP NAMES "linux/seccomp.h")
but I cannot find any command telling CMake to use the found header. For example:
target_include_directories(<target_name> ${SECCOMP})
or globally:
include_directories(${SECCOMP})
I belive that CMakeLists.txt should be fixed. It is not a platform dependent solution.

CLion: issue with Cmake configuration types

I understand that by default, Clion creates the binary files for a project loaded in Clion in all the four configurations:
(Debug;Release;MinSizeRel;RelWithDebInfo)
as well as one called: __default__.
I am using a third party cmake module which downloads an external project in a way that add_subdirectory() can be run on it so it would be included in the root project.
add_subdirectory(${downloaded_proj_src_dir} ${downloaded_proj_bin_dir} EXCLUDE_FROM_ALL)
In this setup, if I decide to place the child project outside the binary directory of the root project, I get:
Error:Binary directories outside of CMake build directory are not supported. Most likely this error is caused by an add_subdirectory command with an explicitly specified binary_dir argument.
which is an understandable restriction by CMake.
now if I instead decide to set the binary directory of the downloaded project in a subdirectory of the binary directory of the parent project, ie:
set(downloaded_proj_bin_dir "${CMAKE_BINARY_DIR}/${downloaded_proj}-build")
...
add_subdirectory(${downloaded_proj_src_dir} ${downloaded_proj_bin_dir} EXCLUDE_FROM_ALL)
I will get the file created in the parent binary directory of all the build configurations because ${CMAKE_BINARY_DIR} is different for each configuration. To avoid seeing all these directories listed on the project view sidebar, I have set the CMAKE_CONFIGURATION_TYPES to be Debug. But even then, I get:
Error:Configuration Debug
The current CMakeCache.txt directory /path/Debug/downloaded_proj_bin/CMakeCache.txt is different than the directory /path/__default__/downloaded_proj_bin/CMakeCache.txt where CMakeCache.txt was created. This may result in binaries being created in the wrong place. If you are not sure, reedit the CMakeCache.txt
Clearly something is going on with this __default__ configuration which I don't understand. So the question is, what is the significance of this default configuration and why should there be a conflict here?
P.s. Setting the configuration to __default__ does not solve the problem as I will have a __default__0 configuration created instead and get the same error.
Update: some further observations
My enviornment variables set in IDE don't have any effect on the cmake builds.
Cmake "options" however which presumably will be passed as arguments to cmake do seem to work.
-D CMAKE_CONFIGURATION_TYPES=Debug.
When I specify the command line option, I get
Warning:Manually-specified variables were not used by the project:
CMAKE_CONFIGURATION_TYPES
But it clearly does have the effect of no longer creating the other build configurations. My guess is that this message relates to the __default__ build which is ignoring the argument.
Even in the case of specifying CMAKE_CONFIGURATION_TYPES in the IDE, I still get the additional __default__ build which is apparently unaffected by the CMAKE_CONFIGURATION_TYPES assignment.
Logging: message("Build type: ${CMAKE_BUILD_TYPE} ) does not return any build_type.
Outputting message(and generator: ${CMAKE_GENERATOR} ") returns "Unix-make files" for both, so both are being generated with the same generator.
Taking a diff from the CMakeCache.txt files, I can see that they are identical.
Do you have in DownloadProject.cmake the right setting? for:
set(_DownloadProjectDir "${CMAKE_CURRENT_LIST_DIR}")
I had the same problem trying to set google test(with the help of https://github.com/Crascit/DownloadProject) and my _DownloadProjectDir was setted as "test". Maybe when I moved this cmake file in my project Clion changed that automatically.
So, it turns out that you can sort this out quite easily by adding the following line above line 145 in DownloadProject.cmake:
file(REMOVE "${DL_ARGS_DOWNLOAD_DIR}/CMakeCache.txt")
This seems to be because CLion copies the default across to the other configurations and doesn't clear the cache. This is a problem only because DownloadProject creates a project within the project (I think...). Anyway, deleting this file before configuring the CMakeLists.txt by-passes this issue. I'll submit a pull request to the DownloadProject repository as this doesn't seem to have any adverse effects when not using CLion.