| // 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. |
| |
| // ignore-msvc -- sprintf isn't a symbol in msvcrt? maybe a #define? |
| |
| #![feature(libc, std_misc)] |
| |
| extern crate libc; |
| |
| use std::ffi::{CStr, CString}; |
| use libc::{c_char, c_int}; |
| |
| |
| extern { |
| fn sprintf(s: *mut c_char, format: *const c_char, ...) -> c_int; |
| } |
| |
| unsafe fn check<T, F>(expected: &str, f: F) where F: FnOnce(*mut c_char) -> T { |
| let mut x = [0 as c_char; 50]; |
| f(&mut x[0] as *mut c_char); |
| assert_eq!(expected.as_bytes(), CStr::from_ptr(x.as_ptr()).to_bytes()); |
| } |
| |
| pub fn main() { |
| |
| unsafe { |
| // Call with just the named parameter |
| let c = CString::new(&b"Hello World\n"[..]).unwrap(); |
| check("Hello World\n", |s| sprintf(s, c.as_ptr())); |
| |
| // Call with variable number of arguments |
| let c = CString::new(&b"%d %f %c %s\n"[..]).unwrap(); |
| check("42 42.500000 a %d %f %c %s\n\n", |s| { |
| sprintf(s, c.as_ptr(), 42, 42.5f64, 'a' as c_int, c.as_ptr()); |
| }); |
| |
| // Make a function pointer |
| let x: unsafe extern fn(*mut c_char, *const c_char, ...) -> c_int = sprintf; |
| |
| // A function that takes a function pointer |
| unsafe fn call(p: unsafe extern fn(*mut c_char, *const c_char, ...) -> c_int) { |
| // Call with just the named parameter |
| let c = CString::new(&b"Hello World\n"[..]).unwrap(); |
| check("Hello World\n", |s| sprintf(s, c.as_ptr())); |
| |
| // Call with variable number of arguments |
| let c = CString::new(&b"%d %f %c %s\n"[..]).unwrap(); |
| check("42 42.500000 a %d %f %c %s\n\n", |s| { |
| sprintf(s, c.as_ptr(), 42, 42.5f64, 'a' as c_int, c.as_ptr()); |
| }); |
| } |
| |
| // Pass sprintf directly |
| call(sprintf); |
| |
| // Pass sprintf indirectly |
| call(x); |
| } |
| |
| } |