diff --git a/nuttx/lib/lib_rint.c b/nuttx/lib/lib_rint.c
index 73600f6bf..632c6632d 100644
--- a/nuttx/lib/lib_rint.c
+++ b/nuttx/lib/lib_rint.c
@@ -72,7 +72,7 @@
  * Private Variables
  ************************************************************/
 
-double_t rint(double x)
+double_t rint(double_t x)
 {
   double_t retValue;