EXPECT_EQ(0, TF_OperationNumControlOutputs(scalar));
  EXPECT_EQ(0, TF_OperationGetControlOutputs(scalar, control_ops, 100));

  EXPECT_EQ(0, TF_OperationNumControlInputs(feed));
  EXPECT_EQ(0, TF_OperationGetControlInputs(feed, control_ops, 100));
  EXPECT_EQ(0, TF_OperationNumControlOutputs(feed));
  EXPECT_EQ(0, TF_OperationGetControlOutputs(feed, control_ops, 100));

  EXPECT_EQ(0, TF_OperationNumControlInputs(neg));

// modification of the graph can increase the number of control
// outputs.  Returns the number of control outputs (should match
// TF_OperationNumControlOutputs(oper)).
TF_CAPI_EXPORT extern int TF_OperationGetControlOutputs(
    TF_Operation* oper, TF_Operation** control_outputs,
    int max_control_outputs);

// TF_AttrMetadata describes the value of an attribute on an operation.
typedef struct TF_AttrMetadata {

  int count = 0;
  for (const auto* edge : oper->node.out_edges()) {
    if (edge->IsControlEdge() && !edge->dst()->IsSink()) {
      ++count;
    }
  }
  return count;
}

int TF_OperationGetControlOutputs(TF_Operation* oper,
                                  TF_Operation** control_outputs,
                                  int max_control_outputs) {
  int count = 0;