diff --git a/CMakeLists.txt b/CMakeLists.txt
index a0982e8..6cb119c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,8 @@ project(bluelib C)
 
 include (TestBigEndian)
 
+set(CMAKE_C_STANDARD 99)
+set(CMAKE_C_EXTENSIONS OFF)
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 set(b_modules core object serial term cmd io)