# FindProtobuf

Locate and configure the Google Protocol Buffers library.

New in version 3.6: Support for `find_package()` version checks.

Changed in version 3.6: All input and output variables use the `Protobuf_` prefix. Variables with `PROTOBUF_` prefix are still supported for compatibility.

The following variables can be set and are optional:

`Protobuf_SRC_ROOT_FOLDER`

  When compiling with MSVC, if this cache variable is set the protobuf-default VS project build locations (vsprojects/Debug and vsprojects/Release or vsprojects/x64/Debug and vsprojects/x64/Release) will be searched for libraries and binaries.

`Protobuf_IMPORT_DIRS`

  List of additional directories to be searched for imported .proto files.

`Protobuf_DEBUG`

  New in version 3.6.

  Show debug messages.

`Protobuf_USE_STATIC_LIBS`

  New in version 3.9.

  Set to ON to force the use of the static libraries. Default is OFF.

Defines the following variables:

`Protobuf_FOUND`

  Found the Google Protocol Buffers library (libprotobuf & header files)

`Protobuf_VERSION`

  New in version 3.6.

  Version of package found.

`Protobuf_INCLUDE_DIRS`

  Include directories for Google Protocol Buffers

`Protobuf_LIBRARIES`

  The protobuf libraries

`Protobuf_PROTOC_LIBRARIES`

  The protoc libraries

`Protobuf_LITE_LIBRARIES`

  The protobuf-lite libraries

New in version 3.9: The following `IMPORTED` targets are also defined:

`protobuf::libprotobuf`

  The protobuf library.

`protobuf::libprotobuf-lite`

  The protobuf lite library.

`protobuf::libprotoc`

  The protoc library.

`protobuf::protoc`

  New in version 3.10: The protoc compiler.

The following cache variables are also available to set or use:

`Protobuf_LIBRARY`

  The protobuf library

`Protobuf_PROTOC_LIBRARY`

  The protoc library

`Protobuf_INCLUDE_DIR`

  The include directory for protocol buffers

`Protobuf_PROTOC_EXECUTABLE`

  The protoc compiler

`Protobuf_LIBRARY_DEBUG`

  The protobuf library (debug)

`Protobuf_PROTOC_LIBRARY_DEBUG`

  The protoc library (debug)

`Protobuf_LITE_LIBRARY`

  The protobuf lite library

`Protobuf_LITE_LIBRARY_DEBUG`

  The protobuf lite library (debug)

Example:

    find_package(Protobuf REQUIRED)
    include_directories(${Protobuf_INCLUDE_DIRS})
    include_directories(${CMAKE_CURRENT_BINARY_DIR})
    protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS foo.proto)
    protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS EXPORT_MACRO DLL_EXPORT foo.proto)
    protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS DESCRIPTORS PROTO_DESCS foo.proto)
    protobuf_generate_python(PROTO_PY foo.proto)
    add_executable(bar bar.cc ${PROTO_SRCS} ${PROTO_HDRS})
    target_link_libraries(bar ${Protobuf_LIBRARIES})

Note

The `protobuf_generate_cpp` and `protobuf_generate_python` functions and `add_executable()` or `add_library()` calls only work properly within the same directory.

protobuf_generate_cpp

  Add custom commands to process `.proto` files to C++:

      protobuf_generate_cpp (<SRCS> <HDRS>
          [DESCRIPTORS <DESC>] [EXPORT_MACRO <MACRO>] [<ARGN>...])

  `SRCS`

    Variable to define with autogenerated source files

  `HDRS`

    Variable to define with autogenerated header files

  `DESCRIPTORS`

    New in version 3.10: Variable to define with autogenerated descriptor files, if requested.

  `EXPORT_MACRO`

    is a macro which should expand to `__declspec(dllexport)` or `__declspec(dllimport)` depending on what is being compiled.

  `ARGN`

    `.proto` files

protobuf_generate_python

  New in version 3.4.

  Add custom commands to process `.proto` files to Python:

      protobuf_generate_python (<PY> [<ARGN>...])

  `PY`

    Variable to define with autogenerated Python files

  `ARGN`

    `.proto` files

protobuf_generate

  New in version 3.13.

  Automatically generate source files from `.proto` schema files at build time:

      protobuf_generate (
          TARGET <target>
          [LANGUAGE <lang>]
          [OUT_VAR <out_var>]
          [EXPORT_MACRO <macro>]
          [PROTOC_OUT_DIR <dir>]
          [PLUGIN <plugin>]
          [PLUGIN_OPTIONS <plugin_options>]
          [DEPENDENCIES <depends]
          [PROTOS <protobuf_files>]
          [IMPORT_DIRS <dirs>]
          [GENERATE_EXTENSIONS <extensions>]
          [PROTOC_OPTIONS <protoc_options>]
          [APPEND_PATH])

  `APPEND_PATH`

    A flag that causes the base path of all proto schema files to be added to `IMPORT_DIRS`.

  `LANGUAGE`

    A single value: cpp or python. Determines what kind of source files are being generated. Defaults to cpp.

  `OUT_VAR`

    Name of a CMake variable that will be filled with the paths to the generated source files.

  `EXPORT_MACRO`

    Name of a macro that is applied to all generated Protobuf message classes and extern variables. It can, for example, be used to declare DLL exports.

  `PROTOC_OUT_DIR`

    Output directory of generated source files. Defaults to `CMAKE_CURRENT_BINARY_DIR`.

  `PLUGIN`

    New in version 3.21.

    An optional plugin executable. This could, for example, be the path to `grpc_cpp_plugin`.

  `PLUGIN_OPTIONS`

    New in version 3.28.

    Additional options provided to the plugin, such as `generate_mock_code=true` for the gRPC cpp plugin.

  `DEPENDENCIES`

    New in version 3.28.

    Arguments forwarded to the `DEPENDS` of the underlying `add_custom_command` invocation.

  `TARGET`

    CMake target that will have the generated files added as sources.

  `PROTOS`

    List of proto schema files. If omitted, then every source file ending in proto of `TARGET` will be used.

  `IMPORT_DIRS`

    A common parent directory for the schema files. For example, if the schema file is `proto/helloworld/helloworld.proto` and the import directory `proto/` then the generated files are `${PROTOC_OUT_DIR}/helloworld/helloworld.pb.h` and `${PROTOC_OUT_DIR}/helloworld/helloworld.pb.cc`.

  `GENERATE_EXTENSIONS`

    If LANGUAGE is omitted then this must be set to the extensions that protoc generates.

  `PROTOC_OPTIONS`

    New in version 3.28.

    Additional arguments that are forwarded to protoc.

  Example:

      find_package(gRPC CONFIG REQUIRED)
      find_package(Protobuf REQUIRED)
      add_library(ProtoTest Test.proto)
      target_link_libraries(ProtoTest PUBLIC gRPC::grpc++)
      protobuf_generate(TARGET ProtoTest)
      protobuf_generate(
          TARGET ProtoTest
          LANGUAGE grpc
          PLUGIN protoc-gen-grpc=$<TARGET_FILE:gRPC::grpc_cpp_plugin>
          PLUGIN_OPTIONS generate_mock_code=true
          GENERATE_EXTENSIONS .grpc.pb.h .grpc.pb.cc)