pragma once and for all
diff --git a/libsel4allocman/include/allocman/cspace/single_level.h b/libsel4allocman/include/allocman/cspace/single_level.h
index 9482848..dc6e401 100644
--- a/libsel4allocman/include/allocman/cspace/single_level.h
+++ b/libsel4allocman/include/allocman/cspace/single_level.h
@@ -10,8 +10,7 @@
  * @TAG(DATA61_BSD)
  */
 
-#ifndef _ALLOCMAN_CSPACE_SINGLE_LEVEL_H_
-#define _ALLOCMAN_CSPACE_SINGLE_LEVEL_H_
+#pragma once
 
 #include <autoconf.h>
 #include <stdlib.h>
@@ -72,4 +71,3 @@
     };
 }
 
-#endif