--- Net2/sys/file.h	2018/04/24 18:03:58	1.1
+++ Net2/sys/file.h	2018/04/24 18:16:23	1.1.1.2
@@ -30,9 +30,13 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)file.h	7.10 (Berkeley) 6/4/91
+ *	from: @(#)file.h	7.10 (Berkeley) 6/4/91
+ *	file.h,v 1.3 1993/05/20 16:22:15 cgd Exp
  */
 
+#ifndef _SYS_FILE_H_
+#define _SYS_FILE_H_
+
 #include <sys/fcntl.h>
 #include <sys/unistd.h>
 
@@ -71,3 +75,5 @@ extern int maxfiles;		/* kernel limit on
 extern int nfiles;		/* actual number of open files */
 
 #endif /* KERNEL */
+
+#endif /* !_SYS_FILE_H_ */