diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9f1d877..ca645de 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 2.8)
 
 set(CMAKE_BUILD_TYPE DEBUG)
 
-set(CMAKE_CXX_FLAGS "-std=c++11 -pthread")
+set(CMAKE_CXX_FLAGS "-std=c++11 -pthread -fsigned-char")
 set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 set(CMAKE_CXX_FLAGS_RELEASE "-O2")
 set(CMAKE_EXE_LINKER_FLAGS "-pthread")