Install/Use QtProtobuf in custom Qt installation location

[cooked]

Question Hi, how do I build and install QtProtobuf to be used by a Qt installation (qmake) not on the system path? Additional context I'm on Debian and I have Qt installed in /home//Qt as is standard for an installation via the Qt online installer. I'd like to use QtProtobuf with this Qt and not the system one (i.e. pulled/installed from apt repo). What are the build and install configuration parameters i should use during QtProtobuf build?

[semlanik]

Hi @cooked , as per https://github.com/semlanik/qtprotobuf#build-1 you need to specify a path to the Qt cmake directory using CMAKE_PREFIX_PATH variable.

[cooked]

Hi @semlanik thanks for the prompt reply. Indeed I'm following that step. Do I need to install after building? if yes, do I have to specify the installation folder to be my custom Qt folder?

[cooked]

Hi @cooked , as per https://github.com/semlanik/qtprotobuf#build-1 you need to specify a path to the Qt cmake directory using CMAKE_PREFIX_PATH variable.

when I run the configuration it does not complete and I get an error about the script not finding the "qmake"

-- Looking for unistd.h - found -- Found WrapProtobuf: /usr/include found components: Protoc Generator Protobuf CMake Error at cmake/QtProtobufInternalHelpers.cmake:117 (message): Could not find qmake executable Call Stack (most recent call first): src/protobuf/CMakeLists.txt:1 (qt_protobuf_extract_qt_variable) -- Configuring incomplete, errors occurred!

Please note that I've omitted to install any library related to qt form the list in https://github.com/semlanik/qtprotobuf#for-ubuntu-1910-or-higher

[semlanik]

Hi @semlanik thanks for the prompt reply. Indeed I'm following that step. Do I need to install after building? if yes, do I have to specify the installation folder to be my custom Qt folder?

Yeah, it only supports prefixed builds or as a part of a top-level project for now. You may specify the install prefix outside the Qt installation, it's ok. But when you use qmake make sure that you included qtprotobuf modules manually.

[semlanik]

Hi @cooked , as per https://github.com/semlanik/qtprotobuf#build-1 you need to specify a path to the Qt cmake directory using CMAKE_PREFIX_PATH variable.

when I run the configuration it does not complete and I get an error about the script not finding the "qmake"

-- Looking for unistd.h - found -- Found WrapProtobuf: /usr/include found components: Protoc Generator Protobuf CMake Error at cmake/QtProtobufInternalHelpers.cmake:117 (message): Could not find qmake executable Call Stack (most recent call first): src/protobuf/CMakeLists.txt:1 (qt_protobuf_extract_qt_variable) -- Configuring incomplete, errors occurred!

Please note that I've omitted to install any library related to qt form the list in https://github.com/semlanik/qtprotobuf#for-ubuntu-1910-or-higher

Sorry, previous comment was wrong(about protoc). I didn't read the log carefully.

What Qt version do you use?

Overall specifying -DCMAKE_FIND_ROOT_PATH=/home/Qt/path_before_bin should solve the issue

[cooked]

Overall specifying -DCMAKE_FIND_ROOT_PATH=/home/Qt/path_before_bin should solve the issue thanks @semlanik this got me through the configuration steps successfully. but I'm not entirely sure about the install though.

I use Qt 5.15.2 that is located in /home/username/Qt/5.15.2/gcc_64

do I have to add -DCMAKE_INSTALL_PREFIX=/home/username/Qt/5.15.2/gcc_64 (is this path correct or a specific subfolder shall be specified?) to the configuration flags to be able to install qtprotobuf into my Qt installation ?

[semlanik]

@cooked yep, it should work. Let me know if it doesn't :)

[cooked]

@semlanik thanks for the great support. I managed to get my dream configuration and build with the following lines. Hope this can help others :-)

cd qtprotobuf
mkdir build
cd build
/home/$USER/Qt/Tools/CMake/bin/cmake .. -DCMAKE_PREFIX_PATH="/home/$USER/Qt/5.15.2/gcc_64/lib/cmake" -DCMAKE_FIND_ROOT_PATH=/home/$USER/Qt/Qt/5.15.2/gcc_64 -DCMAKE_INSTALL_PREFIX=/home/$USER/Qt/5.15.2/gcc_64 -DQT_PROTOBUF_MAKE_TESTS=FALSE -DQT_PROTOBUF_MAKE_EXAMPLES=FALSE
/home/$USER/Qt/Tools/CMake/bin/cmake --build . -j8 --target install