--- a/src/google/protobuf/repeated_ptr_field.h
+++ b/src/google/protobuf/repeated_ptr_field.h
@@ -805,7 +805,7 @@
 
 // Appends all `std::string` values from `from` to this instance.
 template <>
-void RepeatedPtrFieldBase::MergeFrom<std::string>(
+PROTOBUF_EXPORT void RepeatedPtrFieldBase::MergeFrom<std::string>(
     const RepeatedPtrFieldBase& from);
 
 
