diff --git a/src/unix/notbsd/mod.rs b/src/unix/notbsd/mod.rs
index 9e0916a09eca6..8ee7cf815c5b3 100644
--- a/src/unix/notbsd/mod.rs
+++ b/src/unix/notbsd/mod.rs
@@ -253,6 +253,7 @@ pub const RUSAGE_SELF: ::c_int = 0;
 pub const O_RDONLY: ::c_int = 0;
 pub const O_WRONLY: ::c_int = 1;
 pub const O_RDWR: ::c_int = 2;
+pub const O_TMPFILE: ::c_int = 0o20000000 | O_DIRECTORY;
 
 pub const SOCK_CLOEXEC: ::c_int = O_CLOEXEC;