diff --git a/rmw/include/rmw/rmw.h b/rmw/include/rmw/rmw.h
index 2ff25456..4b6385ed 100644
--- a/rmw/include/rmw/rmw.h
+++ b/rmw/include/rmw/rmw.h
@@ -205,6 +205,23 @@ rmw_take_with_info(
   bool * taken,
   rmw_message_info_t * message_info);
 
+RMW_PUBLIC
+RMW_WARN_UNUSED
+rmw_ret_t
+rmw_take_raw(
+  const rmw_subscription_t * subscription,
+  rmw_message_raw_t * raw_message,
+  bool * taken);
+
+RMW_PUBLIC
+RMW_WARN_UNUSED
+rmw_ret_t
+rmw_take_raw_with_info(
+  const rmw_subscription_t * subscription,
+  rmw_message_raw_t * raw_message,
+  bool * taken,
+  rmw_message_info_t * message_info);
+
 RMW_PUBLIC
 RMW_WARN_UNUSED
 rmw_client_t *
diff --git a/rmw/include/rmw/types.h b/rmw/include/rmw/types.h
index 689f0e53..2782c5cf 100644
--- a/rmw/include/rmw/types.h
+++ b/rmw/include/rmw/types.h
@@ -232,7 +232,7 @@ typedef struct RMW_PUBLIC_TYPE rmw_message_raw_t
 {
   // already serialized message data
   char * buffer;
-  size_t buffer_length;
+  unsigned int buffer_length;
 } rmw_message_raw_t;
 
 enum {RMW_QOS_POLICY_DEPTH_SYSTEM_DEFAULT = 0};