diff --git a/absl/flags/internal/parse.h b/absl/flags/internal/parse.h
new file mode 100644
index 0000000..fd3aca6
--- /dev/null
+++ b/absl/flags/internal/parse.h
@@ -0,0 +1,48 @@
+//
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_FLAGS_INTERNAL_PARSE_H_
+#define ABSL_FLAGS_INTERNAL_PARSE_H_
+
+#include <string>
+#include <vector>
+
+#include "absl/flags/declare.h"
+
+ABSL_DECLARE_FLAG(std::vector<std::string>, flagfile);
+ABSL_DECLARE_FLAG(std::vector<std::string>, fromenv);
+ABSL_DECLARE_FLAG(std::vector<std::string>, tryfromenv);
+ABSL_DECLARE_FLAG(std::vector<std::string>, undefok);
+
+namespace absl {
+namespace flags_internal {
+
+enum class ArgvListAction { kRemoveParsedArgs, kKeepParsedArgs };
+enum class UsageFlagsAction { kHandleUsage, kIgnoreUsage };
+enum class OnUndefinedFlag {
+  kIgnoreUndefined,
+  kReportUndefined,
+  kAbortIfUndefined
+};
+
+std::vector<char*> ParseCommandLineImpl(int argc, char* argv[],
+                                        ArgvListAction arg_list_act,
+                                        UsageFlagsAction usage_flag_act,
+                                        OnUndefinedFlag on_undef_flag);
+
+}  // namespace flags_internal
+}  // namespace absl
+
+#endif  // ABSL_FLAGS_INTERNAL_PARSE_H_