68 lines
2.2 KiB
Rust
68 lines
2.2 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// ignore-msvc -- sprintf isn't a symbol in msvcrt? maybe a #define?
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#![feature(libc, std_misc)]
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extern crate libc;
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use std::ffi::{CStr, CString};
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use libc::{c_char, c_int};
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extern {
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fn sprintf(s: *mut c_char, format: *const c_char, ...) -> c_int;
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}
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unsafe fn check<T, F>(expected: &str, f: F) where F: FnOnce(*mut c_char) -> T {
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let mut x = [0 as c_char; 50];
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f(&mut x[0] as *mut c_char);
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assert_eq!(expected.as_bytes(), CStr::from_ptr(x.as_ptr()).to_bytes());
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}
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pub fn main() {
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unsafe {
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// Call with just the named parameter
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let c = CString::new(&b"Hello World\n"[..]).unwrap();
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check("Hello World\n", |s| sprintf(s, c.as_ptr()));
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// Call with variable number of arguments
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let c = CString::new(&b"%d %f %c %s\n"[..]).unwrap();
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check("42 42.500000 a %d %f %c %s\n\n", |s| {
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sprintf(s, c.as_ptr(), 42, 42.5f64, 'a' as c_int, c.as_ptr());
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});
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// Make a function pointer
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let x: unsafe extern fn(*mut c_char, *const c_char, ...) -> c_int = sprintf;
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// A function that takes a function pointer
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unsafe fn call(fp: unsafe extern fn(*mut c_char, *const c_char, ...) -> c_int) {
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// Call with just the named parameter
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let c = CString::new(&b"Hello World\n"[..]).unwrap();
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check("Hello World\n", |s| fp(s, c.as_ptr()));
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// Call with variable number of arguments
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let c = CString::new(&b"%d %f %c %s\n"[..]).unwrap();
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check("42 42.500000 a %d %f %c %s\n\n", |s| {
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fp(s, c.as_ptr(), 42, 42.5f64, 'a' as c_int, c.as_ptr());
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});
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}
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// Pass sprintf directly
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call(sprintf);
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// Pass sprintf indirectly
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call(x);
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}
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}
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