diff --git a/libio/fileops.c b/libio/fileops.c
index 001794d05a7..cfa97313d0d 100644
--- a/libio/fileops.c
+++ b/libio/fileops.c
@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <string.h>
+#include <unistd.h>
 #include <errno.h>
 #ifndef errno
 extern int errno;