1 files changed, 5 insertions, 1 deletions
diff --git a/src/basic/fd-util.h b/src/basic/fd-util.h
index 1ca10f0383..5ce1592eeb 100644
--- a/src/basic/fd-util.h
+++ b/src/basic/fd-util.h
@@ -21,13 +21,17 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <stdio.h>
 #include <dirent.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <sys/socket.h>
 
 #include "macro.h"
 
+/* Make sure we can distinguish fd 0 and NULL */
+#define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
+#define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
+
 int close_nointr(int fd);
 int safe_close(int fd);
 void safe_close_pair(int p[]);