diff --git a/libavfilter/parseutils.h b/libavfilter/parseutils.h
index 7b78d89ffd..8ad7b8b5e6 100644
--- a/libavfilter/parseutils.h
+++ b/libavfilter/parseutils.h
@@ -38,7 +38,7 @@
  * terminating char
  * @param term a 0-terminated list of terminating chars
  * @return the malloced unescaped string, which must be av_freed by
- * the user
+ * the user, NULL in case of allocation failure
  */
 char *av_get_token(const char **buf, const char *term);