This section contains reference documentation for working with protocol buffer classes in C++.

#include <google/protobuf/compiler/plugin.h>
namespace google::protobuf::compiler

Front-end for protoc code generator plugins written in C++.

To implement a protoc plugin in C++, simply write an implementation of CodeGenerator, then create a main() function like:

int main(int argc, char* argv[[]]) {
  MyCodeGenerator generator;
  return google::protobuf::compiler::PluginMain(argc, argv, &generator);

You must link your plugin against libprotobuf and libprotoc.

The core part of PluginMain is to invoke the given CodeGenerator on a CodeGeneratorRequest to generate a CodeGeneratorResponse. This part is abstracted out and made into function GenerateCode so that it can be reused, for example, to implement a variant of PluginMain that does some preprocessing on the input CodeGeneratorRequest before feeding the request to the given code generator.

To get protoc to use the plugin, do one of the following:

  • Place the plugin binary somewhere in the PATH and give it the name "protoc-gen-NAME" (replacing "NAME" with the name of your plugin). If you then invoke protoc with the parameter –NAME_out=OUT_DIR (again, replace "NAME" with your plugin's name), protoc will invoke your plugin to generate the output, which will be placed in OUT_DIR.
  • Place the plugin binary anywhere, with any name, and pass the –plugin parameter to protoc to direct it to your plugin like so:

    protoc --plugin=protoc-gen-NAME=path/to/mybinary --NAME_out=OUT_DIR

    On Windows, make sure to include the .exe suffix:

    protoc --plugin=protoc-gen-NAME=path/to/mybinary.exe --NAME_out=OUT_DIR

Classes in this file

File Members

These definitions are not part of any class.
PluginMain(int argc, char * argv, const CodeGenerator * generator)
Implements main() for a protoc plugin exposing the given code generator.
GenerateCode(const CodeGeneratorRequest & request, const CodeGenerator & generator, CodeGeneratorResponse * response, std::string * error_msg)
Generates code using the given code generator. more...

bool compiler::GenerateCode(
        const CodeGeneratorRequest & request,
        const CodeGenerator & generator,
        CodeGeneratorResponse * response,
        std::string * error_msg)

Generates code using the given code generator.

Returns true if the code generation is successful. If the code generation fails, error_msg may be populated to describe the failure cause.