/// Declare a new thread local storage key of type `std::thread::LocalKey`.
///
+/// # Syntax
+///
+/// The macro wraps any number of static declarations and makes them thread local.
+/// Each static may be public or private, and attributes are allowed. Example:
+///
+/// ```
+/// use std::cell::RefCell;
+/// thread_local! {
+/// pub static FOO: RefCell<u32> = RefCell::new(1);
+///
+/// #[allow(unused)]
+/// static BAR: RefCell<f32> = RefCell::new(1.0);
+/// }
+/// # fn main() {}
+/// ```
+///
/// See [LocalKey documentation](thread/struct.LocalKey.html) for more
/// information.
#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]
#[allow_internal_unstable]
macro_rules! thread_local {
- (static $name:ident: $t:ty = $init:expr) => (
- static $name: $crate::thread::LocalKey<$t> =
+ // rule 0: empty (base case for the recursion)
+ () => {};
+
+ // rule 1: process multiple declarations where the first one is private
+ ($(#[$attr:meta])* static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
+ thread_local!($(#[$attr])* static $name: $t = $init); // go to rule 2
+ thread_local!($($rest)*);
+ );
+
+ // rule 2: handle a single private declaration
+ ($(#[$attr:meta])* static $name:ident: $t:ty = $init:expr) => (
+ $(#[$attr])* static $name: $crate::thread::LocalKey<$t> =
__thread_local_inner!($t, $init);
);
- (pub static $name:ident: $t:ty = $init:expr) => (
- pub static $name: $crate::thread::LocalKey<$t> =
+
+ // rule 3: handle multiple declarations where the first one is public
+ ($(#[$attr:meta])* pub static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => (
+ thread_local!($(#[$attr])* pub static $name: $t = $init); // go to rule 4
+ thread_local!($($rest)*);
+ );
+
+ // rule 4: handle a single public declaration
+ ($(#[$attr:meta])* pub static $name:ident: $t:ty = $init:expr) => (
+ $(#[$attr])* pub static $name: $crate::thread::LocalKey<$t> =
__thread_local_inner!($t, $init);
);
}
--- /dev/null
+// Copyright 2016 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.
+
+#![deny(missing_docs)]
+//! this tests the syntax of `thread_local!`
+
+thread_local! {
+ // no docs
+ #[allow(unused)]
+ static FOO: i32 = 42;
+ /// docs
+ pub static BAR: String = String::from("bar");
+}
+thread_local!(static BAZ: u32 = 0);
+
+fn main() {}