diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs index 08f0aa2f0d206..d856f9b465e04 100644 --- a/src/libstd/thread/mod.rs +++ b/src/libstd/thread/mod.rs @@ -163,6 +163,7 @@ use crate::ffi::{CStr, CString}; use crate::fmt; use crate::io; use crate::mem; +use crate::num::NonZeroU64; use crate::panic; use crate::panicking; use crate::str; @@ -1036,7 +1037,7 @@ pub fn park_timeout(dur: Duration) { /// [`Thread`]: ../../std/thread/struct.Thread.html #[stable(feature = "thread_id", since = "1.19.0")] #[derive(Eq, PartialEq, Clone, Copy, Hash, Debug)] -pub struct ThreadId(u64); +pub struct ThreadId(NonZeroU64); impl ThreadId { // Generate a new unique thread ID. @@ -1044,7 +1045,7 @@ impl ThreadId { // We never call `GUARD.init()`, so it is UB to attempt to // acquire this mutex reentrantly! static GUARD: mutex::Mutex = mutex::Mutex::new(); - static mut COUNTER: u64 = 0; + static mut COUNTER: u64 = 1; unsafe { let _guard = GUARD.lock(); @@ -1058,7 +1059,7 @@ impl ThreadId { let id = COUNTER; COUNTER += 1; - ThreadId(id) + ThreadId(NonZeroU64::new(id).unwrap()) } } } @@ -1484,9 +1485,10 @@ fn _assert_sync_and_send() { mod tests { use super::Builder; use crate::any::Any; + use crate::mem; use crate::sync::mpsc::{channel, Sender}; use crate::result; - use crate::thread; + use crate::thread::{self, ThreadId}; use crate::time::Duration; use crate::u32; @@ -1716,6 +1718,11 @@ mod tests { thread::sleep(Duration::from_millis(2)); } + #[test] + fn test_size_of_option_thread_id() { + assert_eq!(mem::size_of::>(), mem::size_of::()); + } + #[test] fn test_thread_id_equal() { assert!(thread::current().id() == thread::current().id());