diff --git a/libbfqio/bfqio.c b/libbfqio/bfqio.c
index 5ab05a80..98bd2da4 100644
--- a/libbfqio/bfqio.c
+++ b/libbfqio/bfqio.c
@@ -23,6 +23,7 @@
 #include <pthread.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 static int __rtio_cgroup_supported = -1;
 static pthread_once_t __rtio_init_once = PTHREAD_ONCE_INIT;