[libcxx] r291331 - thread: implement sleep_for on Windows

[Saleem Abdulrasool via cfe-commits]

Author: compnerd
Date: Fri Jan  6 20:48:30 2017
New Revision: 291331

URL: http://llvm.org/viewvc/llvm-project?rev=291331&view=rev
Log:
thread: implement sleep_for on Windows

Windows does not provide an implementation of `nanosleep`.  Round up the
time duration to the nearest ms and use `Sleep`.  Although this may
over-sleep, there is no hard real-time guarantee on the wake, so
sleeping a bit more is better than under-sleeping as it within the
specification.

Modified:
    libcxx/trunk/src/thread.cpp

Modified: libcxx/trunk/src/thread.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/thread.cpp?rev=291331&r1=291330&r2=291331&view=diff
==============================================================================
--- libcxx/trunk/src/thread.cpp (original)
+++ libcxx/trunk/src/thread.cpp Fri Jan  6 20:48:30 2017
@@ -117,6 +117,12 @@ sleep_for(const chrono::nanoseconds& ns)
     using namespace chrono;
     if (ns > nanoseconds::zero())
     {
+#if defined(_LIBCPP_WIN32API)
+        milliseconds ms = duration_cast<milliseconds>(ns);
+        if (ns > duration_cast<nanoseconds>(ms))
+          ++ms;
+        Sleep(ms.count());
+#else
         seconds s = duration_cast<seconds>(ns);
         timespec ts;
         typedef decltype(ts.tv_sec) ts_sec;
@@ -134,6 +140,7 @@ sleep_for(const chrono::nanoseconds& ns)
 
         while (nanosleep(&ts, &ts) == -1 && errno == EINTR)
             ;
+#endif
     }
 }