docstrings
diff --git a/src/cpp/codegen/codegen_init.cc b/src/cpp/codegen/codegen_init.cc
index 917f1bb..37abbad 100644
--- a/src/cpp/codegen/codegen_init.cc
+++ b/src/cpp/codegen/codegen_init.cc
@@ -34,5 +34,11 @@
#include <grpc++/impl/codegen/core_codegen_interface.h>
#include <grpc++/impl/codegen/grpc_library.h>
+/// Initializes the global gRPC variables for the codegen library. These will
+/// stay null in the absence of of grpc++ library. In this case, no gRPC
+/// features such as the ability to perform calls will be available. Trying to
+/// perform them would result in a segmentation fault when trying to deference
+/// the following nulled globals.
+
grpc::CoreCodegenInterface* grpc::g_core_codegen_interface = nullptr;
grpc::GrpcLibraryInterface* grpc::g_glip = nullptr;