Mqtt

Sergey_85

Hello, can I use the mqtt library in the free version, if so, why can't I connect it?

jsulm

@Sergey_85 Do you mean https://doc.qt.io/qt-6/qtmqtt-index.html ? It is available under GPLv3, so yes you can use it freely as long as you do not violate GPLv3.

"if so, why can't I connect it?" - who knows, you did not provide any details...
And what does "connect" mean here? You can't link? You can't establish a connection?

Sergey_85

Sorry for explaining it wrong. When I add to Cmakefile.txt
find_package(Qt6 REQUIRED COMPONENTS Mqtt)
target_link_libraries(mytarget PRIVATE Qt6::Mqtt)
I get the error:
C:\Projects_Qt\MqttTest\CMakeLists.txt:14: error: Found package configuration file:

C:/Qt/6.8.0/mingw_64/lib/cmake/Qt6/Qt6Config.cmake

but it set Qt6_FOUND to FALSE so package "Qt6" is considered to be NOT
FOUND. Reason given by package:

Failed to find required Qt component "Mqtt".

Expected Config file at
"C:/Qt/6.8.0/mingw_64/lib/cmake/Qt6Mqtt/Qt6MqttConfig.cmake" does NOT exist

Sergey_85

@jsulm Through Qt Maintenance Tool I can't find Mqtt module to install.

Pl45m4

@Sergey_85 said in Mqtt:

Through Qt Maintenance Tool I can't find Mqtt module to install.

Unless something has changed, which apparently isn't the case here, you have to build QMQTT yourself from source, as it's not available in Online Installer for open source users.

See:

https://forum.qt.io/topic/90033/qt-mqtt-not-available

Sergey_85

@Pl45m4 Thank you for your quick response, I will try to figure it out using the link you provided.

Sergey_85

Thanks, with MinGW, I managed to connect Mqtt from manually assembled libraries. Can you please tell me how to solve the issue with the compilation Android app?

jsulm

@Sergey_85 said in Mqtt:

Can you please tell me how to solve the issue with the compilation Android app?

Please tell us first what issue it is...
Did you build mqtt for Android?

Sergey_85

@jsulm First I needed to do it for a window application, I did it, now I need to connect mqtt to a mobile application but there is aarch64-v8 architecture so compilation does not work.

jsulm

@Sergey_85 said in Mqtt:

but there is aarch64-v8 architecture so compilation does not work.

Just build it using Android NDK or your Android Kit in QtCreator.

And please, "does not work" does not tell anything. You should say what you tried and what happened.

Sergey_85

@jsulm I can't build sources for Arm64-v8a

cmake .. \
  -DCMAKE_PREFIX_PATH=/home/ph/opt/Qt/6.8.0/gcc_64 \
  -DCMAKE_TOOLCHAIN_FILE=/home/ph/Android/Sdk/ndk/26.1.10909125/build/cmake/android.toolchain.cmake \
  -DANDROID_ABI=arm64-v8a \
  -DANDROID_NATIVE_API_LEVEL=21
-- The CXX compiler identification is Clang 17.0.2
-- The C compiler identification is Clang 17.0.2
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /home/ph/Android/Sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /home/ph/Android/Sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/linux-x86_64/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
CMake Error at CMakeLists.txt:14 (find_package):
  Could not find a package configuration file provided by "Qt6" (requested
  version 6.8.0) 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.


-- Configuring incomplete, errors occurred!

Maybe I'm doing something wrong?
Qt6Config.cmake is located at the specified path

jsulm

@Sergey_85 Did you install Qt for Android?

Sergey_85

@jsulm Yes

jsulm

@Sergey_85 said in Mqtt:

-DCMAKE_PREFIX_PATH=/home/ph/opt/Qt/6.8.0/gcc_64

This doesn't look like a path to Qt for Android

Sergey_85

@jsulm I tried -DCMAKE_PREFIX_PATH=/home/ph/opt/Qt/6.8.1/android_arm64_v8a

jsulm

@Sergey_85 And what happened? Does /home/ph/opt/Qt/6.8.0/gcc_64 contain Qt6Config.cmake or qt6-config.cmake like CMake requested in the error message?

Sergey_85

@jsulm yes, the Qt6Config.cmake file is also in the folder
/home/ph/opt/Qt/6.8.1/android_arm64_v8a/lib/cmake/Qt6/Qt6Config.cmake

I haven't compiled from sources before, what's in the kit was enough for me, so I apologize if I'm asking something wrong or providing incomplete information, I'm confused(

jsulm

@Sergey_85 The I think it should be

-DCMAKE_PREFIX_PATH=/home/ph/opt/Qt/6.8.1/android_arm64_v8a/lib/cmake/Qt6

Sergey_85

@jsulm ```
cmake ..
-DCMAKE_PREFIX_PATH=/home/ph/opt/Qt/6.8.1/android_arm64_v8a/lib/cmake/Qt6
-DCMAKE_TOOLCHAIN_FILE=/home/ph/Android/Sdk/ndk/26.1.10909125/build/cmake/android.toolchain.cmake
-DANDROID_ABI=arm64-v8a
-DANDROID_NATIVE_API_LEVEL=21
-- The CXX compiler identification is Clang 17.0.2
-- The C compiler identification is Clang 17.0.2
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /home/ph/Android/Sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /home/ph/Android/Sdk/ndk/26.1.10909125/toolchains/llvm/prebuilt/linux-x86_64/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
CMake Error at CMakeLists.txt:14 (find_package):
Could not find a package configuration file provided by "Qt6" (requested
version 6.8.1) 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.

-- Configuring incomplete, errors occurred!

jsulm

@Sergey_85 Try with a clean build folder (best to create a fresh one)