diff --git a/src/seq/query.c b/src/seq/query.c
index bdd25491..b49c99bb 100644
--- a/src/seq/query.c
+++ b/src/seq/query.c
@@ -8,6 +8,7 @@
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
+#include <errno.h>
 
 /**
  * alsaseq_get_seq_sysname: