diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3e9b862..3098445 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,7 +50,7 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 if(MSVC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W2")
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "[Cc]lang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror -Wextra -Wshadow")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror -Wextra -Wshadow -Weffc++ -Wsign-compare -Wshadow -Wwrite-strings -Wpointer-arith -Winit-self -Wconversion -Wno-sign-conversion")
 endif()
 
 add_library(cxxopts INTERFACE)
diff --git a/test/options.cpp b/test/options.cpp
index b98bade..dccb047 100644
--- a/test/options.cpp
+++ b/test/options.cpp
@@ -36,7 +36,7 @@ class Argv {
 
   private:
 
-  std::vector<std::unique_ptr<char[]>> m_args;
+  std::vector<std::unique_ptr<char[]>> m_args{};
   std::unique_ptr<const char*[]> m_argv;
   int m_argc;
 };