diff --git a/Makefile b/Makefile
index b2fd31b..c58f79d 100644
--- a/Makefile
+++ b/Makefile
@@ -23,3 +23,8 @@ fmt:
 
 gen_mock:
 	go generate ./...
+
+syntax:
+	GOOS=windows go build ./...
+	GOOS=linux go build ./...
+	GOOS=darwin go build ./...
diff --git a/fs_utils_windows.go b/fs_utils_windows.go
index 3da719b..f873965 100644
--- a/fs_utils_windows.go
+++ b/fs_utils_windows.go
@@ -9,11 +9,11 @@ import (
 // reference: os package
 var chmodBits fs.FileMode = 0600
 
-func Uid(from fs.FileInfo) int {
+func toUID(from fs.FileInfo) int {
 	return -1
 }
 
-func Gid(from fs.FileInfo) int {
+func toGID(from fs.FileInfo) int {
 	return -1
 }