diff --git a/newlib/libc/sys/rtems/include/sys/mman.h b/newlib/libc/sys/rtems/include/sys/mman.h
index f75490c96..6e178d83d 100644
--- a/newlib/libc/sys/rtems/include/sys/mman.h
+++ b/newlib/libc/sys/rtems/include/sys/mman.h
@@ -176,6 +176,12 @@
  * Anonymous object constant for shm_open().
  */
 #define	SHM_ANON		((char *)1)
+
+/*
+ * shmflags for shm_open2()
+ */
+#define	SHM_ALLOW_SEALING		0x00000001
+
 #endif /* __BSD_VISIBLE */
 
 /*