diff --git a/libs/midi++2/midi.cc b/libs/midi++2/midi.cc
index 89d74b1b31..5324d7c22f 100644
--- a/libs/midi++2/midi.cc
+++ b/libs/midi++2/midi.cc
@@ -158,7 +158,7 @@ MIDI::byte
 MIDI::decode_controller_name (const char *name)
 
 {
-	char *lparen;
+	const char *lparen;
 	size_t len;
 
 	if ((lparen = strrchr (name, '(')) != 0) {