diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 6a377bd..c34390f 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -2761,7 +2761,7 @@
                                          != 0 )
         {
             mbedtls_printf( " failed\n  ! mbedtls_ssl_tls_prf returned -0x%x\n\n",
-                            -ret );
+                            (unsigned int) -ret );
             goto exit;
         }