Add JoinHandleExt to get the pthread_t on unix platforms

Signed-off-by: Peter Atashian <retep998@gmail.com>

src/libstd/sys/unix/ext/thread.rs

@@ -0,0 +1,43 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Unix-specific extensions to primitives in the `std::process` module.
+
+#![unstable(feature = "thread_extensions", issue = "29791")]
+
+use os::unix::raw::{pthread_t};
+use sys_common::{AsInner, IntoInner};
+use thread::{JoinHandle};
+
+#[unstable(feature = "thread_extensions", issue = "29791")]
+pub type RawPthread = pthread_t;
+
+/// Unix-specific extensions to `std::thread::JoinHandle`
+#[unstable(feature = "thread_extensions", issue = "29791")]
+pub trait JoinHandleExt {
+    /// Extracts the raw pthread_t without taking ownership
+    fn as_pthread_t(&self) -> RawPthread;
+    /// Consumes the thread, returning the raw pthread_t
+    ///
+    /// This function **transfers ownership** of the underlying pthread_t to
+    /// the caller. Callers are then the unique owners of the pthread_t and
+    /// must either detech or join the pthread_t once it's no longer needed.
+    fn into_pthread_t(self) -> RawPthread;
+}
+
+#[unstable(feature = "thread_extensions", issue = "29791")]
+impl<T> JoinHandleExt for JoinHandle<T> {
+    fn as_pthread_t(&self) -> RawPthread {
+        self.as_inner().id() as RawPthread
+    }
+    fn into_pthread_t(self) -> RawPthread {
+        self.into_inner().into_id() as RawPthread
+    }
+}