diff --git a/libifupdown/lifecycle.c b/libifupdown/lifecycle.c
index f0bd2b3..4be5678 100644
--- a/libifupdown/lifecycle.c
+++ b/libifupdown/lifecycle.c
@@ -114,7 +114,7 @@ query_dependents_from_executors(const struct lif_execute_opts *opts, char *const
 	return true;
 }
 
-bool
+static bool
 append_to_buffer(char **buffer, size_t *buffer_len, char **end, const char *value)
 {
 	size_t value_len = strlen (value);