1 extern "C" {
foo() -> i322     pub fn foo() -> i32;
3 }
4 
5 /** Safety doc.
6 
7   # Safety
8 
9 */
10 #[no_mangle]
double_foo() -> i3211 pub unsafe extern "C" fn double_foo() -> i32 {
12     2 * foo()
13 }
14