diff --git a/openbsd/syslog.c b/openbsd/syslog.c
index bba697c..e826ea6 100644
--- a/openbsd/syslog.c
+++ b/openbsd/syslog.c
@@ -2,6 +2,7 @@
 #include <sys/param.h>
 #include <sys/sysctl.h>
 #include <sys/msgbuf.h>
+#include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>