diff --git a/diff.go b/diff.go
index ed2949c..0939435 100644
--- a/diff.go
+++ b/diff.go
@@ -14,7 +14,7 @@ import (
 	"unsafe"
 )
 
-type DiffFlag int
+type DiffFlag uint32
 
 const (
 	DiffFlagBinary    DiffFlag = C.GIT_DIFF_FLAG_BINARY