1 files changed, 1 insertions, 1 deletions
diff --git a/src/util.h b/src/util.h
index ab46540..f4936ec 100644
--- a/src/util.h
+++ b/src/util.h
@@ -68,7 +68,7 @@ enum file_id_type lookup_file_id (struct stat const *);
 void set_queued_output (struct stat const *, bool);
 bool has_queued_output (struct stat const *);
 int stat_file (char const *, struct stat *);
-bool filename_is_safe (char const *);
+bool filename_is_safe (char const *) _GL_ATTRIBUTE_PURE;
 bool cwd_is_root (char const *);
 
 enum file_attributes {