thread.rs.html -- source
Description: Source to the Rust file `src\libstd\sys\windows\thread.rs`.
Keywords: rust, rustlang, rust-lang

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    use crate::io;
    use crate::ffi::CStr;
    use crate::mem;
    use crate::ptr;
    use crate::sys::c;
    use crate::sys::handle::Handle;
    use crate::sys_common::thread::*;
    use crate::time::Duration;

    use libc::c_void;

    use super::to_u16s;

    pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024;

    pub struct Thread {
        handle: Handle
    }

    impl Thread {
        // unsafe: see thread::Builder::spawn_unchecked for safety requirements
        pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>)
                              -> io::Result<Thread> {
            let p = box p;

            // FIXME On UNIX, we guard against stack sizes that are too small but
            // that's because pthreads enforces that stacks are at least
            // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
            // just that below a certain threshold you can't do anything useful.
            // That threshold is application and architecture-specific, however.
            // Round up to the next 64 kB because that's what the NT kernel does,
            // might as well make it explicit.
            let stack_size = (stack + 0xfffe) & (!0xfffe);
            let ret = c::CreateThread(ptr::null_mut(), stack_size,
                                      thread_start, &*p as *const _ as *mut _,
                                      c::STACK_SIZE_PARAM_IS_A_RESERVATION,
                                      ptr::null_mut());

            return if ret as usize == 0 {
                Err(io::Error::last_os_error())
            } else {
                mem::forget(p); // ownership passed to CreateThread
                Ok(Thread { handle: Handle::new(ret) })
            };

            extern "system" fn thread_start(main: *mut c_void) -> c::DWORD {
                unsafe { start_thread(main as *mut u8); }
                0
            }
        }

        pub fn set_name(name: &CStr) {
            if let Ok(utf8) = name.to_str() {
                if let Ok(utf16) = to_u16s(utf8) {
                    unsafe { c::SetThreadDescription(c::GetCurrentThread(), utf16.as_ptr()); };
                };
            };
        }

        pub fn join(self) {
            let rc = unsafe { c::WaitForSingleObject(self.handle.raw(), c::INFINITE) };
            if rc == c::WAIT_FAILED {
                panic!("failed to join on thread: {}",
                       io::Error::last_os_error());
            }
        }

        pub fn yield_now() {
            // This function will return 0 if there are no other threads to execute,
            // but this also means that the yield was useless so this isn't really a
            // case that needs to be worried about.
            unsafe { c::SwitchToThread(); }
        }

        pub fn sleep(dur: Duration) {
            unsafe {
                c::Sleep(super::dur2timeout(dur))
            }
        }

        pub fn handle(&self) -> &Handle { &self.handle }

        pub fn into_handle(self) -> Handle { self.handle }
    }

    #[cfg_attr(test, allow(dead_code))]
    pub mod guard {
        pub type Guard = !;
        pub unsafe fn current() -> Option<Guard> { None }
        pub unsafe fn init() -> Option<Guard> { None }
    }