diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7d6b843..2116669b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.6)
-project(GmSSL)
+project(GmSSL C)
 
 SET(CMAKE_PROJECT_HOMEPAGE_URL "http://gmssl.org")