diff --git a/CMakeLists.txt b/CMakeLists.txt
index e3194cd29ce8b7615178ba893f215d27cac164e5..5739c2a26039426ab544f762e9401445f01e7de7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,6 +68,7 @@ if(ANDROID)
     if(${CMAKE_SYSTEM_VERSION} VERSION_LESS "16")
         message(FATAL_ERROR "Unsupport standalone toolchains with Android API level lower than 16")
     elseif(${CMAKE_SYSTEM_VERSION} VERSION_LESS "21")
+        # TODO: support glog for Android api 16 ~ 19 in the future
         message(WARNING "Using the unofficial git repository <https://github.com/Xreki/glog.git> instead")
     endif()