diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 72854571f..60b111c71 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -550,8 +550,9 @@ int tcp_connect_probe(struct connection *conn)
 
 
 /* This function tries to bind a TCPv4/v6 listener. It may return a warning or
- * an error message in <err> if the message is at most <errlen> bytes long
- * (including '\0'). The return value is composed from ERR_ABORT, ERR_WARN,
+ * an error message in <errmsg> if the message is at most <errlen> bytes long
+ * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.
+ * The return value is composed from ERR_ABORT, ERR_WARN,
  * ERR_ALERT, ERR_RETRYABLE and ERR_FATAL. ERR_NONE indicates that everything
  * was alright and that no message was returned. ERR_RETRYABLE means that an
  * error occurred but that it may vanish after a retry (eg: port in use), and
@@ -568,7 +569,7 @@ int tcp_bind_listener(struct listener *listener, char *errmsg, int errlen)
 	const char *msg = NULL;
 
 	/* ensure we never return garbage */
-	if (errmsg && errlen)
+	if (errlen)
 		*errmsg = 0;
 
 	if (listener->state != LI_ASSIGNED)
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index 3f18770ff..3263ea4ab 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -144,7 +144,10 @@ static void destroy_uxst_socket(const char *path)
 
 /* This function creates a UNIX socket associated to the listener. It changes
  * the state from ASSIGNED to LISTEN. The socket is NOT enabled for polling.
- * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
+ * The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL. It
+ * may return a warning or an error message in <errmsg> if the message is at
+ * most <errlen> bytes long (including '\0'). Note that <errmsg> may be NULL if
+ * <errlen> is also zero.
  */
 static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen)
 {
@@ -158,7 +161,7 @@ static int uxst_bind_listener(struct listener *listener, char *errmsg, int errle
 	int ret;
 
 	/* ensure we never return garbage */
-	if (errmsg && errlen)
+	if (errlen)
 		*errmsg = 0;
 
 	if (listener->state != LI_ASSIGNED)