grpc/include/grpcpp/impl/codegen/README.md

# Welcome to `impl/codegen`

## Why is this directory here?

This directory exists so that generated code can include selected files upon
which it depends without having to depend on the entire gRPC C++ library. This
is particularly relevant for users of bazel, particularly if they use the
multi-lingual `proto_library` target type. Generated code that uses this target
only depends on the gRPC C++ targets associated with these header files, not the
entire gRPC C++ codebase since that would make the build time of these types of
targets excessively large (particularly when they are not even C++ specific).

## What should user code do?

User code should *not* include anything from this directory. Only generated code
and gRPC library code should include contents from this directory. User code
should instead include contents from the main `grpcpp` directory or its
accessible subcomponents like `grpcpp/support`.