src/libstd/sys/windows/thread.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use prelude::v1::*;
  12
  13 use alloc::boxed::FnBox;
  14 use cmp;
  15 use io;
  16 use libc::{self, c_void, DWORD};
  17 use mem;
  18 use ptr;
  19 use sys::c;
  20 use sys::handle::Handle;
  21 use sys_common::stack::RED_ZONE;
  22 use sys_common::thread::*;
  23 use time::Duration;
  24
  25 pub struct Thread {
  26     handle: Handle
  27 }
  28
  29 impl Thread {
  30     pub unsafe fn new<'a>(stack: usize, p: Box<FnBox() + 'a>)
  31                           -> io::Result<Thread> {
  32         let p = box p;
  33
  34         // FIXME On UNIX, we guard against stack sizes that are too small but
  35         // that's because pthreads enforces that stacks are at least
  36         // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
  37         // just that below a certain threshold you can't do anything useful.
  38         // That threshold is application and architecture-specific, however.
  39         // For now, the only requirement is that it's big enough to hold the
  40         // red zone.  Round up to the next 64 kB because that's what the NT
  41         // kernel does, might as well make it explicit.  With the current
  42         // 20 kB red zone, that makes for a 64 kB minimum stack.
  43         let stack_size = (cmp::max(stack, RED_ZONE) + 0xfffe) & (-0xfffe - 1);
  44         let ret = c::CreateThread(ptr::null_mut(), stack_size as libc::size_t,
  45                                   thread_start, &*p as *const _ as *mut _,
  46                                   0, ptr::null_mut());
  47
  48         return if ret as usize == 0 {
  49             Err(io::Error::last_os_error())
  50         } else {
  51             mem::forget(p); // ownership passed to CreateThread
  52             Ok(Thread { handle: Handle::new(ret) })
  53         };
  54
  55         #[no_stack_check]
  56         extern "system" fn thread_start(main: *mut libc::c_void) -> DWORD {
  57             unsafe { start_thread(main); }
  58             0
  59         }
  60     }
  61
  62     pub fn set_name(_name: &str) {
  63         // Windows threads are nameless
  64         // The names in MSVC debugger are obtained using a "magic" exception,
  65         // which requires a use of MS C++ extensions.
  66         // See https://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
  67     }
  68
  69     pub fn join(self) {
  70         use libc::consts::os::extra::INFINITE;
  71         unsafe { c::WaitForSingleObject(self.handle.raw(), INFINITE); }
  72     }
  73
  74     pub fn yield_now() {
  75         // This function will return 0 if there are no other threads to execute,
  76         // but this also means that the yield was useless so this isn't really a
  77         // case that needs to be worried about.
  78         unsafe { c::SwitchToThread(); }
  79     }
  80
  81     pub fn sleep(dur: Duration) {
  82         unsafe {
  83             c::Sleep(super::dur2timeout(dur))
  84         }
  85     }
  86 }
  87
  88 pub mod guard {
  89     pub unsafe fn main() -> usize { 0 }
  90     pub unsafe fn current() -> usize { 0 }
  91     pub unsafe fn init() {}
  92 }