qt_add_protobuf
Generates Qt-based C++ source code using a protobuf schema
Note: This command is in technology preview and may change in future releases.
This command was introduced in Qt 6.5.
Usually qtprotobufgen would be invoked through CMake using the qt_add_protobuf macro.
qt_add_protobuf(<target>
PROTO_FILES <file> ...
[COPY_COMMENTS]
[GENERATE_PACKAGE_SUBFOLDERS]
[EXTRA_NAMESPACE <namespace>]
[EXPORT_MACRO <infix>]
[PROTO_INCLUDES <path> ...]
[OUTPUT_DIRECTORY <dir>]
[OUTPUT_HEADERS <var>]
[OUTPUT_TARGETS <var>]
)
The source files generated by qtprotobufgen are then added to the target. If the target already exists, the files are added to the target source list. If the target doesn't exist, it is created as a library which you must link to.
Arguments
COPY_COMMENTSCopies comments from.protofiles. If provided in the parameter list, comments related to messages and fields are copied to generated header files.GENERATE_PACKAGE_SUBFOLDERSgenerates a folder structure for the generated files matching the.protofile's package name. For examplepackage io.qt.test;would put the generated files intoio/qt/test/.EXTRA_NAMESPACEis an optional namespace that will be used for the generated classes. The classes are always generated in a namespace whose name is the same as the package name specified in the.protofile. If this option is used then everything will be nested inside the extra namespace.EXPORT_MACROis the base name of the symbol export macro used for the generated code. The generated macro name is constructed asQPB_<EXPORT_MACRO>_EXPORT. If the option is not set, the macro is not generated.PROTO_FILESis the list of.protofiles that will be used in the generation procedure.PROTO_INCLUDESis the list of directories that will be searched for dependencies.OUTPUT_DIRECTORYis the directory where the generated files will be put. By default, the current directory (while evaluating the function) is used.OUTPUT_HEADERScan be used to specify a variable that will hold the list of headers created by the function. This list can be useful for custom project install rules.OUTPUT_TARGETScan be used to specify a variable that will hold the list of targets created by the function. This list can be useful for custom project install rules.
Example
cmake_minimum_required(VERSION 3.16...3.22)
project(MyThings)
find_package(Qt6 REQUIRED COMPONENTS Protobuf)
qt_standard_project_setup()
qt_add_protobuf(MyMessages
GENERATE_PACKAGE_SUBFOLDERS
PROTO_FILES
path/to/message.proto
path/to/other_message.proto
PROTO_INCLUDES
/path/to/proto/include
)
qt_add_executable(MyApp main.cpp)
target_link_libraries(MyApp PRIVATE MyMessages)
In the example above we generate a library called MyMessages which contains the message types defined in the paths passed to the PROTO_FILES option. We use the GENERATE_PACKAGE_SUBFOLDERS option to generate a folder structure for the generated files. And the PROTO_INCLUDES option tells protoc to look for dependencies/imports in the specified directories.
We then create a target for an executable called MyApp which we link to the MyMessages library.
See also The qtprotobufgen Tool.