Coverage Report

Created: 2026-03-28 06:55

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
/rust/registry/src/index.crates.io-1949cf8c6b5b557f/num_threads-0.1.6/src/lib.rs
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//! Minimum supported Rust version: 1.28
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use std::num::NonZeroUsize;
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#[cfg_attr(any(target_os = "linux", target_os = "android"), path = "linux.rs")]
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#[cfg_attr(target_os = "freebsd", path = "freebsd.rs")]
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#[cfg_attr(any(target_os = "macos", target_os = "ios"), path = "apple.rs")]
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mod imp;
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/// Obtain the number of threads currently part of the active process. Returns `None` if the number
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/// of threads cannot be determined.
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pub fn num_threads() -> Option<NonZeroUsize> {
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    imp::num_threads()
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}
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/// Determine if the current process is single-threaded. Returns `None` if the number of threads
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/// cannot be determined.
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pub fn is_single_threaded() -> Option<bool> {
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    num_threads().map(|n| n.get() == 1)
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}
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#[cfg(test)]
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mod test {
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    use std::num::NonZeroUsize;
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    // Run each expression in its own thread.
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    macro_rules! threaded {
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        ($first:expr;) => {
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            $first;
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        };
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        ($first:expr; $($rest:expr;)*) => {
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            $first;
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            ::std::thread::spawn(|| {
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                threaded!($($rest;)*);
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            })
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            .join()
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            .unwrap();
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        };
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    }
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    #[test]
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    fn num_threads() {
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        threaded! {
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(1));
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(2));
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(3));
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(4));
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(5));
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            assert_eq!(super::num_threads().map(NonZeroUsize::get), Some(6));
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        }
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    }
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    #[test]
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    fn is_single_threaded() {
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        threaded! {
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            assert_eq!(super::is_single_threaded(), Some(true));
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            assert_eq!(super::is_single_threaded(), Some(false));
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            assert_eq!(super::is_single_threaded(), Some(false));
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            assert_eq!(super::is_single_threaded(), Some(false));
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            assert_eq!(super::is_single_threaded(), Some(false));
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            assert_eq!(super::is_single_threaded(), Some(false));
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        }
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    }
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}