diff --git a/format.sh b/format.sh
index 4e464c9780..16adddc764 100755
--- a/format.sh
+++ b/format.sh
@@ -33,4 +33,7 @@ astyle ${FILES} \
 find ${FILES} -exec sed -i -e '$a\' {} \;
 
 # lint
-clang-tidy -p . ${FILES} -- ${COMPILER_OPTS}
+C_FILES=$(echo "$FILES" | grep '\.c$')
+if [[ ! -z $C_FILES ]]; then
+    clang-tidy -p . ${C_FILES} -- ${COMPILER_OPTS}
+fi