| // Copyright 2013 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. |
| |
| extern crate libc; |
| use std::c_str::CString; |
| use libc::{c_char, c_int}; |
| |
| // ignore-fast doesn't like extern crate |
| |
| extern { |
| fn sprintf(s: *mut c_char, format: *c_char, ...) -> c_int; |
| } |
| |
| unsafe fn check<T>(expected: &str, f: |*mut c_char| -> T) { |
| let mut x = [0i8, ..50]; |
| f(&mut x[0] as *mut c_char); |
| let res = CString::new(&x[0], false); |
| assert_eq!(expected, res.as_str().unwrap()); |
| } |
| |
| pub fn main() { |
| |
| unsafe { |
| // Call with just the named parameter |
| "Hello World\n".with_c_str(|c| { |
| check("Hello World\n", |s| sprintf(s, c)); |
| }); |
| |
| // Call with variable number of arguments |
| "%d %f %c %s\n".with_c_str(|c| { |
| check("42 42.500000 a %d %f %c %s\n\n", |s| { |
| sprintf(s, c, 42i, 42.5f64, 'a' as c_int, c); |
| }) |
| }); |
| |
| // Make a function pointer |
| let x: unsafe extern "C" fn(*mut c_char, *c_char, ...) -> c_int = sprintf; |
| |
| // A function that takes a function pointer |
| unsafe fn call(p: unsafe extern "C" fn(*mut c_char, *c_char, ...) -> c_int) { |
| // Call with just the named parameter via fn pointer |
| "Hello World\n".with_c_str(|c| { |
| check("Hello World\n", |s| p(s, c)); |
| }); |
| |
| // Call with variable number of arguments |
| "%d %f %c %s\n".with_c_str(|c| { |
| check("42 42.500000 a %d %f %c %s\n\n", |s| { |
| p(s, c, 42i, 42.5f64, 'a' as c_int, c); |
| }) |
| }); |
| } |
| |
| // Pass sprintf directly |
| call(sprintf); |
| |
| // Pass sprintf indirectly |
| call(x); |
| } |
| |
| } |