diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 874a3a1b..0ac4bee9 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -424,7 +424,7 @@ strio_s_new(int argc, VALUE *argv, VALUE klass)
 }
 
 /*
- * Returns +false+.  Just for compatibility to IO.
+ * Returns +false+; for compatibility with IO.
  */
 static VALUE
 strio_false(VALUE self)