diff --git a/utshell-0.5/r_input/src/lib.rs b/utshell-0.5/r_input/src/lib.rs
index 317b024bc6e6d99ad9b5818fd650c3880e83af72..99337681add11977350f13ed579c745e28221987 100644
--- a/utshell-0.5/r_input/src/lib.rs
+++ b/utshell-0.5/r_input/src/lib.rs
@@ -162,4 +162,29 @@ macro_rules! QUIT {
             throw_to_top_level();
         }
     };
+}
+
+#[macro_export]
+macro_rules! ALLOCATE_BUFFERS {
+    ($n:expr) => {
+        if $n >= nbuffers {
+            allocate_buffers($n);
+        }
+    };
+}
+#[macro_export]
+macro_rules! SET_CLOSE_ON_EXEC {
+    ($fd:expr) => {
+        fcntl($fd, 2, 1)
+    };
+}
+#[macro_export]
+macro_rules! max {
+    ($a: expr, $b: expr) => {
+        if $a > $b {
+            $a
+        } else {
+            $b
+        }
+    };
 }
\ No newline at end of file