/
linkage1.rs
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/
linkage1.rs
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// 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.
// ignore-win32
// ignore-android
// ignore-macos
// aux-build:linkage1.rs
#![feature(linkage)]
extern crate other = "linkage1";
extern {
#[linkage = "extern_weak"]
static foo: *const int;
#[linkage = "extern_weak"]
static something_that_should_never_exist: *mut int;
}
fn main() {
// It appears that the --as-needed flag to linkers will not pull in a dynamic
// library unless it satisfies a non weak undefined symbol. The 'other' crate
// is compiled as a dynamic library where it would only be used for a
// weak-symbol as part of an executable, so the dynamic library would be
// discarded. By adding and calling `other::bar`, we get around this problem.
other::bar();
assert!(!foo.is_null());
assert_eq!(unsafe { *foo }, 3);
assert!(something_that_should_never_exist.is_null());
}