diff --git a/src/header/fcntl/mod.rs b/src/header/fcntl/mod.rs
--- a/src/header/fcntl/mod.rs
+++ b/src/header/fcntl/mod.rs
@@ -9,0 +10 @@
+    header::unistd::close,
@@ -75,0 +77,17 @@
+
+    if cmd == F_DUPFD_CLOEXEC {
+        let new_fd = Sys::fcntl(fildes, F_DUPFD_CLOEXEC, arg).or_minus_one_errno();
+        if new_fd >= 0 {
+            return new_fd;
+        }
+
+        let new_fd = Sys::fcntl(fildes, F_DUPFD, arg).or_minus_one_errno();
+        if new_fd < 0 {
+            return -1;
+        }
+        if Sys::fcntl(new_fd, F_SETFD, FD_CLOEXEC as c_ulonglong).or_minus_one_errno() < 0 {
+            let _ = close(new_fd);
+            return -1;
+        }
+        return new_fd;
+    }