| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Checks that extern fn pointers implement the full range of Fn traits. |
| |
| use std::ops::{Fn,FnMut,FnOnce}; |
| |
| fn square(x: isize) -> isize { x * x } |
| |
| fn call_it<F:Fn(isize)->isize>(f: &F, x: isize) -> isize { |
| f(x) |
| } |
| |
| fn call_it_mut<F:FnMut(isize)->isize>(f: &mut F, x: isize) -> isize { |
| f(x) |
| } |
| |
| fn call_it_once<F:FnOnce(isize)->isize>(f: F, x: isize) -> isize { |
| f(x) |
| } |
| |
| fn main() { |
| let x = call_it(&square, 22); |
| let y = call_it_mut(&mut square, 22); |
| let z = call_it_once(square, 22); |
| assert_eq!(x, square(22)); |
| assert_eq!(y, square(22)); |
| assert_eq!(z, square(22)); |
| } |
