diff --git a/tools/midi_dump.c b/tools/midi_dump.c
index accfeb6..8192628 100644
--- a/tools/midi_dump.c
+++ b/tools/midi_dump.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <unistd.h>
 #include <assert.h>
 #include <jack/jack.h>
 #include <jack/midiport.h>