diff --git a/ostd/filesystem.hh b/ostd/filesystem.hh
index c9ed029..31196ca 100644
--- a/ostd/filesystem.hh
+++ b/ostd/filesystem.hh
@@ -507,7 +507,7 @@ private:
     DirectoryStream *p_stream;
 };
 
-DirectoryRange DirectoryStream::iter() {
+inline DirectoryRange DirectoryStream::iter() {
     return DirectoryRange(*this);
 }