diff --git a/include/nuttx/mm/iob.h b/include/nuttx/mm/iob.h
index 9bf291f39b8..b0911d281fe 100644
--- a/include/nuttx/mm/iob.h
+++ b/include/nuttx/mm/iob.h
@@ -466,7 +466,7 @@ int iob_get_queue_count(FAR struct iob_queue_s *queue);
  ****************************************************************************/
 
 #if CONFIG_IOB_NCHAINS > 0
-size_t iob_get_queue_size(FAR struct iob_queue_s *queue);
+unsigned int iob_get_queue_size(FAR struct iob_queue_s *queue);
 #endif /* CONFIG_IOB_NCHAINS > 0 */
 
 /****************************************************************************
diff --git a/mm/iob/iob_get_queue_size.c b/mm/iob/iob_get_queue_size.c
index 46deb2b76f1..28f304c7438 100644
--- a/mm/iob/iob_get_queue_size.c
+++ b/mm/iob/iob_get_queue_size.c
@@ -40,11 +40,11 @@
  *
  ****************************************************************************/
 
-size_t iob_get_queue_size(FAR struct iob_queue_s *queue)
+unsigned int iob_get_queue_size(FAR struct iob_queue_s *queue)
 {
   FAR struct iob_qentry_s *iobq;
+  unsigned int total = 0;
   FAR struct iob_s *iob;
-  size_t total = 0;
 
   for (iobq = queue->qh_head; iobq != NULL; iobq = iobq->qe_flink)
     {
diff --git a/net/tcp/tcp_ioctl.c b/net/tcp/tcp_ioctl.c
index b96b62b5c6c..00e56972fb6 100644
--- a/net/tcp/tcp_ioctl.c
+++ b/net/tcp/tcp_ioctl.c
@@ -27,6 +27,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <debug.h>
+#include <errno.h>
 
 #include <net/if.h>
 
@@ -65,7 +66,7 @@ int tcp_ioctl(FAR struct tcp_conn_s *conn,
           iob_get_queue_size(&conn->readahead);
         break;
       default:
-        ret = -EINVAL;
+        ret = -ENOTTY;
         break;
     }
 
diff --git a/net/udp/udp_ioctl.c b/net/udp/udp_ioctl.c
index 9121f706744..f9362e4bd76 100644
--- a/net/udp/udp_ioctl.c
+++ b/net/udp/udp_ioctl.c
@@ -27,6 +27,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <debug.h>
+#include <errno.h>
 
 #include <net/if.h>
 
@@ -65,7 +66,7 @@ int udp_ioctl(FAR struct udp_conn_s *conn,
           iob_get_queue_size(&conn->readahead);
         break;
       default:
-        ret = -EINVAL;
+        ret = -ENOTTY;
         break;
     }