From: Christopher Dykes <cdykes@fb.com>
Date: Wed, 4 May 2016 17:27:25 +0000 (-0700)
Subject: Use std::thread::id in Fiber rather than a syscall
X-Git-Tag: 2016.07.26~284
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7d3bbfee07d6216cebf403e975bea355e154e1a9;p=folly.git

Use std::thread::id in Fiber rather than a syscall

Summary: syscall() doesn't exist on Windows, but std::thread::id is standardized, and can do what we need it for, so use it instead.

Reviewed By: yfeldblum

Differential Revision: D3256064

fb-gh-sync-id: efddac82c117ccd8a53c8c93248529000b4326a5
fbshipit-source-id: efddac82c117ccd8a53c8c93248529000b4326a5
---

diff --git a/folly/experimental/fibers/Fiber.cpp b/folly/experimental/fibers/Fiber.cpp
index 67ea620d..54f086d1 100644
--- a/folly/experimental/fibers/Fiber.cpp
+++ b/folly/experimental/fibers/Fiber.cpp
@@ -35,14 +35,8 @@ namespace fibers {
 namespace {
 static const uint64_t kMagic8Bytes = 0xfaceb00cfaceb00c;
 
-pid_t localThreadId() {
-  // __thread doesn't allow non-const initialization.
-  // OSX doesn't support thread_local.
-  static FOLLY_TLS pid_t threadId = 0;
-  if (UNLIKELY(threadId == 0)) {
-    threadId = syscall(FOLLY_SYS_gettid);
-  }
-  return threadId;
+std::thread::id localThreadId() {
+  return std::this_thread::get_id();
 }
 
 /* Size of the region from p + nBytes down to the last non-magic value */
diff --git a/folly/experimental/fibers/Fiber.h b/folly/experimental/fibers/Fiber.h
index efa43715..f68df6ce 100644
--- a/folly/experimental/fibers/Fiber.h
+++ b/folly/experimental/fibers/Fiber.h
@@ -184,7 +184,7 @@ class Fiber {
   folly::IntrusiveListHook listHook_; /**< list hook for different FiberManager
                                            queues */
   folly::IntrusiveListHook globalListHook_; /**< list hook for global list */
-  pid_t threadId_{0};
+  std::thread::id threadId_{};
 };
 }
 }