status->status = g->graph.AddGradientDef(std::move(gdef));
}

int TF_GraphNumFunctions(TF_Graph* g) {
  tensorflow::mutex_lock l(g->mu);
  return g->graph.flib_def().num_functions();
}

int TF_GraphGetFunctions(TF_Graph* g, TF_Function** funcs, int max_func,
                         TF_Status* status) {
  tensorflow::FunctionDefLibrary lib;
  {

// Graphs are thread-safe when used as directed below.
typedef struct TF_Graph TF_Graph;

// Return a new graph object.
TF_CAPI_EXPORT extern TF_Graph* TF_NewGraph(void);

// Destroy an options object. Graph will be deleted once no more
// TFSession's are referencing it.
TF_CAPI_EXPORT extern void TF_DeleteGraph(TF_Graph*);

// Operation being built. The underlying graph must outlive this.

}

TF_Graph* TF_NewGraph() { return new TF_Graph; }

void TF_DeleteGraph(TF_Graph* g) {
  if (g == nullptr) return;
  g->mu.lock();
  g->delete_requested = true;
  const bool del = g->sessions.empty();
  g->mu.unlock();
  if (del) delete g;
}

TF_Operation* TF_GraphOperationByName(TF_Graph* graph, const char* oper_name) {
  mutex_lock l(graph->mu);

  TF_DeleteStatus(s);
}

/*
TODO(skyewm): this test currently DCHECKs, change to bad status

TEST(CAPI, InputFromDifferentGraphError) {
  TF_Status* s = TF_NewStatus();
  TF_Graph* g1 = TF_NewGraph();
  TF_Graph* g2 = TF_NewGraph();

  TF_Operation* feed = Placeholder(g1, s);
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);

  // Attempt to create node in g2 with input from g1
  Neg(feed, g2, s);

    options.set_trace_level(tensorflow::RunOptions::NO_TRACE);
  }
  TF_Buffer* ret = TF_NewBuffer();
  TF_CHECK_OK(MessageToBuffer(options, ret));
  return ret;
}

const char* TF_GraphDebugString(TF_Graph* graph, size_t* len) {
  tensorflow::mutex_lock c(graph->mu);
  const auto& debug_str = graph->graph.ToGraphDefDebug().DebugString();
  *len = debug_str.size();
  char* ret = static_cast<char*>(malloc(*len + 1));