// `oper_name` is copied and has no lifetime requirements.
TF_CAPI_EXPORT extern void TF_ImportGraphDefOptionsAddReturnOutput(
    TF_ImportGraphDefOptions* opts, const char* oper_name, int index);

// Returns the number of return outputs added via
// TF_ImportGraphDefOptionsAddReturnOutput().
TF_CAPI_EXPORT extern int TF_ImportGraphDefOptionsNumReturnOutputs(
    const TF_ImportGraphDefOptions* opts);

  opts = TF_NewImportGraphDefOptions();
  TF_ImportGraphDefOptionsSetPrefix(opts, "imported2");
  TF_ImportGraphDefOptionsAddInputMapping(opts, "scalar", 0, {scalar, 0});
  TF_ImportGraphDefOptionsAddReturnOutput(opts, "feed", 0);
  TF_ImportGraphDefOptionsAddReturnOutput(opts, "scalar", 0);
  EXPECT_EQ(2, TF_ImportGraphDefOptionsNumReturnOutputs(opts));
  TF_ImportGraphDefOptionsAddReturnOperation(opts, "scalar");