diff --git a/src/cmocka.c b/src/cmocka.c
index 8cb31ea..611229b 100644
--- a/src/cmocka.c
+++ b/src/cmocka.c
@@ -1379,7 +1379,7 @@
     if (result > valmax - 1) {
         if (error > 0) {
             cm_print_error("%s < 0, errno(%" PRIu64 "): %s\n",
-                        expression, error, strerror(error));
+                           expression, error, strerror((int)error));
         } else {
             cm_print_error("%s < 0\n", expression);
         }