bjoernager/rust
bjoernager/rust
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update and extend some comments, and cfg-out some unused code

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This commit is contained in:
Ralf Jung 2022-08-06 13:04:22 -04:00
parent 138375a74c
commit d13699d0be
3 changed files with 12 additions and 7 deletions
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2
library/std/src/sys_common/thread_local_key.rs
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@ -69,8 +69,10 @@ use crate::sys_common::mutex::StaticMutex;
/// ```ignore (cannot-doctest-private-modules)
/// use tls::os::{StaticKey, INIT};
///
/// // Use a regular global static to store the key.
/// static KEY: StaticKey = INIT;
///
/// // The state provided via `get` and `set` is thread-local.
/// unsafe {
/// assert!(KEY.get().is_null());
/// KEY.set(1 as *mut u8);

3
library/std/src/thread/local.rs
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@ -1036,6 +1036,7 @@ pub mod fast {
}
#[doc(hidden)]
#[cfg(not(target_thread_local))]
pub mod os {
use super::lazy::LazyKeyInner;
use crate::cell::Cell;
@ -1044,6 +1045,8 @@ pub mod os {
use crate::ptr;
use crate::sys_common::thread_local_key::StaticKey as OsStaticKey;
/// Use a regular global static to store this key; the state provided will then be
/// thread-local.
pub struct Key<T> {
// OS-TLS key that we'll use to key off.
os: OsStaticKey,

14
library/std/src/thread/mod.rs
View file

@ -192,14 +192,12 @@ pub use scoped::{scope, Scope, ScopedJoinHandle};
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::local::{AccessError, LocalKey};
// The types used by the thread_local! macro to access TLS keys. Note that there
// are two types, the "OS" type and the "fast" type. The OS thread local key
// type is accessed via platform-specific API calls and is slow, while the fast
// Select the type used by the thread_local! macro to access TLS keys. There
// are three types: "static", "fast", "OS". The "OS" thread local key
// type is accessed via platform-specific API calls and is slow, while the "fast"
// key type is accessed via code generated via LLVM, where TLS keys are set up
// by the elf linker. Note that the OS TLS type is always available: on macOS
// the standard library is compiled with support for older platform versions
// where fast TLS was not available; end-user code is compiled with fast TLS
// where available, but both are needed.
// by the elf linker. "static" is for single-threaded platforms where a global
// static is sufficient.
#[unstable(feature = "libstd_thread_internals", issue = "none")]
#[cfg(target_thread_local)]
@ -210,6 +208,7 @@ pub use self::local::fast::Key as __FastLocalKeyInner;
#[cfg(target_thread_local)]
#[cfg(test)] // when building for tests, use real std's key
pub use realstd::thread::__FastLocalKeyInner;
#[unstable(feature = "libstd_thread_internals", issue = "none")]
#[cfg(target_thread_local)]
#[cfg(test)]
@ -217,6 +216,7 @@ pub use self::local::fast::Key as __FastLocalKeyInnerUnused; // we import this a
#[unstable(feature = "libstd_thread_internals", issue = "none")]
#[doc(hidden)]
#[cfg(not(target_thread_local))]
pub use self::local::os::Key as __OsLocalKeyInner;
#[unstable(feature = "libstd_thread_internals", issue = "none")]
#[cfg(all(target_family = "wasm", not(target_feature = "atomics")))]