diff --git a/src/header/unistd/mod.rs b/src/header/unistd/mod.rs
--- a/src/header/unistd/mod.rs
+++ b/src/header/unistd/mod.rs
@@ -1262,9 +1262,9 @@
 /// Specifications Issue 6, and removed in Issue 7.
 #[deprecated]
 // #[unsafe(no_mangle)]
 pub extern "C" fn vfork() -> pid_t {
-    unimplemented!();
+    unsafe { fork() }
 }
 
 unsafe fn with_argv(