1 files changed, 2 insertions, 2 deletions
diff --git a/src/google/protobuf/util/time_util.h b/src/google/protobuf/util/time_util.h
index 432c9f0a..b8846935 100644
--- a/src/google/protobuf/util/time_util.h
+++ b/src/google/protobuf/util/time_util.h
@@ -237,7 +237,7 @@ inline Duration operator%(const Duration& d1, const Duration& d2) {
   return result %= d2;
 }
 
-inline ostream& operator<<(ostream& out, const Duration& d) {
+inline std::ostream& operator<<(std::ostream& out, const Duration& d) {
   out << google::protobuf::util::TimeUtil::ToString(d);
   return out;
 }
@@ -284,7 +284,7 @@ inline Timestamp operator-(const Timestamp& t, const Duration& d) {
 }
 LIBPROTOBUF_EXPORT Duration operator-(const Timestamp& t1, const Timestamp& t2);
 
-inline ostream& operator<<(ostream& out, const Timestamp& t) {
+inline std::ostream& operator<<(std::ostream& out, const Timestamp& t) {
   out << google::protobuf::util::TimeUtil::ToString(t);
   return out;
 }