<div dir="ltr">Sure! Fixed it up in r337984.</div><div class="gmail_extra"><br><div class="gmail_quote">On 25 July 2018 at 15:03, Eric Fiselier <span dir="ltr"><<a href="mailto:eric@efcs.ca" target="_blank">eric@efcs.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><br><div class="gmail_quote"><span class=""><div dir="ltr">On Wed, Jul 25, 2018 at 3:39 PM Alex L <<a href="mailto:arphaman@gmail.com" target="_blank">arphaman@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Looks like this works:<div><br></div><div><div>+++ b/src/experimental/filesystem/<wbr>filesystem_common.h</div><div>@@ -393,7 +393,7 @@ bool set_file_times(const path& p, std::array<TimeSpec, 2> const& TS,</div><div>                     error_code& ec) {</div><div> #if !defined(_LIBCPP_USE_<wbr>UTIMENSAT)</div><div>   using namespace chrono;</div><div>-  auto Convert = [](long nsec) {</div><div>+  auto Convert = [](long nsec) -> decltype(std::declval<::<wbr>timeval>().tv_usec) {</div><div>     return duration_cast<microseconds>(<wbr>nanoseconds(nsec)).count();</div><div>   };</div><div>   struct ::timeval ConvertedTS[2] = {{TS[0].tv_sec, Convert(TS[0].tv_nsec)},</div></div><div><br></div><div>I will commit this fix in a couple of minutes.</div></div></blockquote><div><br></div></span><div>I think I would prefer an explicit cast to an implicit one since the narrowing is intended, and should be safe.</div><div><br></div><div>Maybe:</div><div><br></div><div>auto Convert [](long nsec) { </div><div>  using int_type = decltype(::timeval::tv_usec);</div><div>  auto dur = duration_cast<microseconds>(<wbr>nanoseconds(nsec)).count();</div><div>  return static_cast<int_type>(dur);</div><div>};</div><div><br></div><div>?</div><div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_extra"><br><div class="gmail_quote">On 25 July 2018 at 14:27, Eric Fiselier <span dir="ltr"><<a href="mailto:eric@efcs.ca" target="_blank">eric@efcs.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto">Thanks. let me know if you want me to take over </div><div class="m_8166487320056533479m_-6165504667961413298HOEnZb"><div class="m_8166487320056533479m_-6165504667961413298h5"><br><div class="gmail_quote"><div dir="ltr">On Wed, Jul 25, 2018, 3:22 PM Alex L, <<a href="mailto:arphaman@gmail.com" target="_blank">arphaman@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On 25 July 2018 at 13:51, Eric Fiselier via cfe-commits <span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" rel="noreferrer" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">Author: ericwf<br>
Date: Wed Jul 25 13:51:49 2018<br>
New Revision: 337960<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=337960&view=rev" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project?rev=337960&view=rev</a><br>
Log:<br>
[libc++] Use __int128_t to represent file_time_type.<br>
<br>
Summary:<br>
The ``file_time_type`` time point is used to represent the write times for files.<br>
Its job is to act as part of a C++ wrapper for less ideal system interfaces. The<br>
underlying filesystem uses the ``timespec`` struct for the same purpose.<br>
<br>
However, the initial implementation of ``file_time_type`` could not represent<br>
either the range or resolution of ``timespec``, making it unsuitable. Fixing<br>
this requires an implementation which uses more than 64 bits to store the<br>
time point.<br>
<br>
I primarily considered two solutions: Using ``__int128_t`` and using a<br>
arithmetic emulation of ``timespec``. Each has its pros and cons, and both<br>
come with more than one complication.<br>
<br>
However, after a lot of consideration, I decided on using `__int128_t`. This patch implements that change.<br>
<br>
Please see the [FileTimeType Design Document](<a href="http://libcxx.llvm.org/docs/DesignDocs/FileTimeType.html" rel="noreferrer noreferrer" target="_blank">http://libcxx.llvm.<wbr>org/docs/DesignDocs/<wbr>FileTimeType.html</a>) for more information.<br>
<br>
Reviewers: mclow.lists, ldionne, joerg, arthur.j.odwyer, EricWF<br>
<br>
Reviewed By: EricWF<br>
<br>
Subscribers: christof, K-ballo, cfe-commits, BillyONeal<br>
<br>
Differential Revision: <a href="https://reviews.llvm.org/D49774" rel="noreferrer noreferrer" target="_blank">https://reviews.llvm.org/<wbr>D49774</a><br>
<br>
Added:<br>
    libcxx/trunk/src/include/<wbr>apple_availability.h<br>
Modified:<br>
    libcxx/trunk/include/<wbr>experimental/filesystem<br>
    libcxx/trunk/src/chrono.cpp<br>
    libcxx/trunk/src/experimental/<wbr>filesystem/filesystem_common.h<br>
    libcxx/trunk/src/experimental/<wbr>filesystem/operations.cpp<br>
    libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/class.<wbr>directory_entry/directory_<wbr>entry.mods/last_write_time.sh.<wbr>cpp<br>
    libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/<wbr>convert_file_time.sh.cpp<br>
    libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.<wbr>filesystem.synopsis/file_time_<wbr>type.pass.cpp<br>
    libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.op.<wbr>funcs/fs.op.last_write_time/<wbr>last_write_time.pass.cpp<br>
<br>
Modified: libcxx/trunk/include/<wbr>experimental/filesystem<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/filesystem?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/include/<wbr>experimental/filesystem?rev=<wbr>337960&r1=337959&r2=337960&<wbr>view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/include/<wbr>experimental/filesystem (original)<br>
+++ libcxx/trunk/include/<wbr>experimental/filesystem Wed Jul 25 13:51:49 2018<br>
@@ -260,7 +260,37 @@ _LIBCPP_PUSH_MACROS<br>
<br>
 _LIBCPP_BEGIN_NAMESPACE_<wbr>EXPERIMENTAL_FILESYSTEM<br>
<br>
-typedef chrono::time_point<std::<wbr>chrono::system_clock>  file_time_type;<br>
+struct _FilesystemClock {<br>
+#if !defined(_LIBCPP_HAS_NO_<wbr>INT128)<br>
+  typedef __int128_t rep;<br>
+  typedef nano period;<br>
+#else<br>
+  typedef long long rep;<br>
+  typedef nano period;<br>
+#endif<br>
+<br>
+  typedef chrono::duration<rep, period> duration;<br>
+  typedef chrono::time_point<_<wbr>FilesystemClock> time_point;<br>
+<br>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = false;<br>
+<br>
+  _LIBCPP_FUNC_VIS static time_point now() noexcept;<br>
+<br>
+  _LIBCPP_INLINE_VISIBILITY<br>
+  static time_t to_time_t(const time_point& __t) noexcept {<br>
+    typedef chrono::duration<rep> __secs;<br>
+    return time_t(<br>
+        chrono::duration_cast<__secs>(<wbr>__t.time_since_epoch()).count(<wbr>));<br>
+  }<br>
+<br>
+  _LIBCPP_INLINE_VISIBILITY<br>
+  static time_point from_time_t(time_t __t) noexcept {<br>
+    typedef chrono::duration<rep> __secs;<br>
+    return time_point(__secs(__t));<br>
+  }<br>
+};<br>
+<br>
+typedef chrono::time_point<_<wbr>FilesystemClock> file_time_type;<br>
<br>
 struct _LIBCPP_TYPE_VIS space_info<br>
 {<br>
<br>
Modified: libcxx/trunk/src/chrono.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/chrono.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/src/<wbr>chrono.cpp?rev=337960&r1=<wbr>337959&r2=337960&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/src/chrono.cpp (original)<br>
+++ libcxx/trunk/src/chrono.cpp Wed Jul 25 13:51:49 2018<br>
@@ -11,27 +11,10 @@<br>
 #include "cerrno"        // errno<br>
 #include "system_error"  // __throw_system_error<br>
 #include <time.h>        // clock_gettime, CLOCK_MONOTONIC and CLOCK_REALTIME<br>
+#include "include/apple_availability.h"<br>
<br>
-#if (__APPLE__)<br>
-#if defined(__ENVIRONMENT_MAC_OS_<wbr>X_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_MAC_OS_X_<wbr>VERSION_MIN_REQUIRED__ >= 101200<br>
-#define _LIBCXX_USE_CLOCK_GETTIME<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_IPHONE_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_IPHONE_OS_<wbr>VERSION_MIN_REQUIRED__ >= 100000<br>
-#define _LIBCXX_USE_CLOCK_GETTIME<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_TV_OS_<wbr>VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_TV_OS_VERSION_<wbr>MIN_REQUIRED__ >= 100000<br>
-#define _LIBCXX_USE_CLOCK_GETTIME<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_WATCH_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_WATCH_OS_<wbr>VERSION_MIN_REQUIRED__ >= 30000<br>
-#define _LIBCXX_USE_CLOCK_GETTIME<br>
-#endif<br>
-#endif // __ENVIRONMENT_.*_VERSION_MIN_<wbr>REQUIRED__<br>
-#else<br>
-#define _LIBCXX_USE_CLOCK_GETTIME<br>
+#if !defined(__APPLE__)<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
 #endif // __APPLE__<br>
<br>
 #if defined(_LIBCPP_WIN32API)<br>
@@ -42,7 +25,7 @@<br>
 #include <winapifamily.h><br>
 #endif<br>
 #else<br>
-#if !defined(CLOCK_REALTIME) || !defined(_LIBCXX_USE_CLOCK_<wbr>GETTIME)<br>
+#if !defined(CLOCK_REALTIME) || !defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME)<br>
 #include <sys/time.h>        // for gettimeofday and timeval<br>
 #endif // !defined(CLOCK_REALTIME)<br>
 #endif // defined(_LIBCPP_WIN32API)<br>
@@ -92,16 +75,16 @@ system_clock::now() _NOEXCEPT<br>
                        static_cast<__int64>(ft.<wbr>dwLowDateTime)};<br>
   return time_point(duration_cast<<wbr>duration>(d - nt_to_unix_epoch));<br>
 #else<br>
-#if defined(_LIBCXX_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_REALTIME)<br>
-    struct timespec tp;<br>
-    if (0 != clock_gettime(CLOCK_REALTIME, &tp))<br>
-        __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");<br>
-    return time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));<br>
+#if defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_REALTIME)<br>
+  struct timespec tp;<br>
+  if (0 != clock_gettime(CLOCK_REALTIME, &tp))<br>
+    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");<br>
+  return time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));<br>
 #else<br>
     timeval tv;<br>
     gettimeofday(&tv, 0);<br>
     return time_point(seconds(tv.tv_sec) + microseconds(tv.tv_usec));<br>
-#endif // _LIBCXX_USE_CLOCK_GETTIME && CLOCK_REALTIME<br>
+#endif // _LIBCPP_USE_CLOCK_GETTIME && CLOCK_REALTIME<br>
 #endif<br>
 }<br>
<br>
@@ -129,7 +112,7 @@ const bool steady_clock::is_steady;<br>
 #if defined(__APPLE__)<br>
<br>
 // Darwin libc versions >= 1133 provide ns precision via CLOCK_UPTIME_RAW<br>
-#if defined(_LIBCXX_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_UPTIME_RAW)<br>
+#if defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_UPTIME_RAW)<br>
 steady_clock::time_point<br>
 steady_clock::now() _NOEXCEPT<br>
 {<br>
@@ -191,7 +174,7 @@ steady_clock::now() _NOEXCEPT<br>
     static FP fp = init_steady_clock();<br>
     return time_point(duration(fp()));<br>
 }<br>
-#endif // defined(_LIBCXX_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_UPTIME_RAW)<br>
+#endif // defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_UPTIME_RAW)<br>
<br>
 #elif defined(_LIBCPP_WIN32API)<br>
<br>
<br>
Modified: libcxx/trunk/src/experimental/<wbr>filesystem/filesystem_common.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/experimental/filesystem/filesystem_common.h?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/src/<wbr>experimental/filesystem/<wbr>filesystem_common.h?rev=<wbr>337960&r1=337959&r2=337960&<wbr>view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/src/experimental/<wbr>filesystem/filesystem_common.h (original)<br>
+++ libcxx/trunk/src/experimental/<wbr>filesystem/filesystem_common.h Wed Jul 25 13:51:49 2018<br>
@@ -23,33 +23,17 @@<br>
<br>
 #include <experimental/filesystem><br>
<br>
-#if (__APPLE__)<br>
-#if defined(__ENVIRONMENT_MAC_OS_<wbr>X_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_MAC_OS_X_<wbr>VERSION_MIN_REQUIRED__ >= 101300<br>
-#define _LIBCXX_USE_UTIMENSAT<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_IPHONE_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_IPHONE_OS_<wbr>VERSION_MIN_REQUIRED__ >= 110000<br>
-#define _LIBCXX_USE_UTIMENSAT<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_TV_OS_<wbr>VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_TV_OS_VERSION_<wbr>MIN_REQUIRED__ >= 110000<br>
-#define _LIBCXX_USE_UTIMENSAT<br>
-#endif<br>
-#elif defined(__ENVIRONMENT_WATCH_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
-#if __ENVIRONMENT_WATCH_OS_<wbr>VERSION_MIN_REQUIRED__ >= 40000<br>
-#define _LIBCXX_USE_UTIMENSAT<br>
-#endif<br>
-#endif // __ENVIRONMENT_.*_VERSION_MIN_<wbr>REQUIRED__<br>
-#else<br>
+#include "../../include/apple_<wbr>availability.h"<br>
+<br>
+#if !defined(__APPLE__)<br>
 // We can use the presence of UTIME_OMIT to detect platforms that provide<br>
 // utimensat.<br>
 #if defined(UTIME_OMIT)<br>
-#define _LIBCXX_USE_UTIMENSAT<br>
+#define _LIBCPP_USE_UTIMENSAT<br>
+#endif<br>
 #endif<br>
-#endif // __APPLE__<br>
<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
+#if !defined(_LIBCPP_USE_<wbr>UTIMENSAT)<br>
 #include <sys/time.h> // for ::utimes as used in __last_write_time<br>
 #endif<br>
<br>
@@ -212,76 +196,119 @@ private:<br>
   ErrorHandler& operator=(ErrorHandler const&) = delete;<br>
 };<br>
<br>
-namespace time_util {<br>
+using chrono::duration;<br>
+using chrono::duration_cast;<br>
<br>
-using namespace chrono;<br>
+using TimeSpec = struct ::timespec;<br>
+using StatT = struct ::stat;<br>
<br>
-template <class FileTimeT,<br>
+template <class FileTimeT, class TimeT,<br>
           bool IsFloat = is_floating_point<typename FileTimeT::rep>::value><br>
-struct fs_time_util_base {<br>
-  static constexpr seconds::rep max_seconds =<br>
-      duration_cast<seconds>(<wbr>FileTimeT::duration::max()).<wbr>count();<br>
-<br>
-  static constexpr nanoseconds::rep max_nsec =<br>
-      duration_cast<nanoseconds>(<wbr>FileTimeT::duration::max() -<br>
-                                 seconds(max_seconds))<br>
+struct time_util_base {<br>
+  using rep = typename FileTimeT::rep;<br>
+  using fs_duration = typename FileTimeT::duration;<br>
+  using fs_seconds = duration<rep>;<br>
+  using fs_nanoseconds = duration<rep, nano>;<br>
+  using fs_microseconds = duration<rep, micro>;<br>
+<br>
+  static constexpr rep max_seconds =<br>
+      duration_cast<fs_seconds>(<wbr>FileTimeT::duration::max()).<wbr>count();<br>
+<br>
+  static constexpr rep max_nsec =<br>
+      duration_cast<fs_nanoseconds>(<wbr>FileTimeT::duration::max() -<br>
+                                    fs_seconds(max_seconds))<br>
           .count();<br>
<br>
-  static constexpr seconds::rep min_seconds =<br>
-      duration_cast<seconds>(<wbr>FileTimeT::duration::min()).<wbr>count();<br>
+  static constexpr rep min_seconds =<br>
+      duration_cast<fs_seconds>(<wbr>FileTimeT::duration::min()).<wbr>count();<br>
<br>
-  static constexpr nanoseconds::rep min_nsec_timespec =<br>
-      duration_cast<nanoseconds>(<br>
-          (FileTimeT::duration::min() - seconds(min_seconds)) + seconds(1))<br>
+  static constexpr rep min_nsec_timespec =<br>
+      duration_cast<fs_nanoseconds>(<br>
+          (FileTimeT::duration::min() - fs_seconds(min_seconds)) +<br>
+          fs_seconds(1))<br>
           .count();<br>
<br>
+private:<br>
+#if _LIBCPP_STD_VER > 11<br>
+  static constexpr fs_duration get_min_nsecs() {<br>
+    return duration_cast<fs_duration>(<br>
+        fs_nanoseconds(min_nsec_<wbr>timespec) -<br>
+        duration_cast<fs_nanoseconds>(<wbr>fs_seconds(1)));<br>
+  }<br>
   // Static assert that these values properly round trip.<br>
-  static_assert((seconds(min_<wbr>seconds) +<br>
-                 duration_cast<microseconds>(<wbr>nanoseconds(min_nsec_timespec)<wbr>)) -<br>
-                        duration_cast<microseconds>(<wbr>seconds(1)) ==<br>
+  static_assert(fs_seconds(min_<wbr>seconds) + get_min_nsecs() ==<br>
                     FileTimeT::duration::min(),<br>
-                "");<br>
+                "value doesn't roundtrip");<br>
+<br>
+  static constexpr bool check_range() {<br>
+    // This kinda sucks, but it's what happens when we don't have __int128_t.<br>
+    if (sizeof(TimeT) == sizeof(rep)) {<br>
+      typedef duration<long long, ratio<3600 * 24 * 365> > Years;<br>
+      return duration_cast<Years>(fs_<wbr>seconds(max_seconds)) > Years(250) &&<br>
+             duration_cast<Years>(fs_<wbr>seconds(min_seconds)) < Years(-250);<br>
+    }<br>
+    return max_seconds >= numeric_limits<TimeT>::max() &&<br>
+           min_seconds <= numeric_limits<TimeT>::min();<br>
+  }<br>
+  static_assert(check_range(), "the representable range is unacceptable small");<br>
+#endif<br>
 };<br>
<br>
-template <class FileTimeT><br>
-struct fs_time_util_base<FileTimeT, true> {<br>
-  static const long long max_seconds;<br>
-  static const long long max_nsec;<br>
-  static const long long min_seconds;<br>
-  static const long long min_nsec_timespec;<br>
+template <class FileTimeT, class TimeT><br>
+struct time_util_base<FileTimeT, TimeT, true> {<br>
+  using rep = typename FileTimeT::rep;<br>
+  using fs_duration = typename FileTimeT::duration;<br>
+  using fs_seconds = duration<rep>;<br>
+  using fs_nanoseconds = duration<rep, nano>;<br>
+  using fs_microseconds = duration<rep, micro>;<br>
+<br>
+  static const rep max_seconds;<br>
+  static const rep max_nsec;<br>
+  static const rep min_seconds;<br>
+  static const rep min_nsec_timespec;<br>
 };<br>
<br>
-template <class FileTimeT><br>
-const long long fs_time_util_base<FileTimeT, true>::max_seconds =<br>
-    duration_cast<seconds>(<wbr>FileTimeT::duration::max()).<wbr>count();<br>
-<br>
-template <class FileTimeT><br>
-const long long fs_time_util_base<FileTimeT, true>::max_nsec =<br>
-    duration_cast<nanoseconds>(<wbr>FileTimeT::duration::max() -<br>
-                               seconds(max_seconds))<br>
+template <class FileTimeT, class TimeT><br>
+const typename FileTimeT::rep<br>
+    time_util_base<FileTimeT, TimeT, true>::max_seconds =<br>
+        duration_cast<fs_seconds>(<wbr>FileTimeT::duration::max()).<wbr>count();<br>
+<br>
+template <class FileTimeT, class TimeT><br>
+const typename FileTimeT::rep time_util_base<FileTimeT, TimeT, true>::max_nsec =<br>
+    duration_cast<fs_nanoseconds>(<wbr>FileTimeT::duration::max() -<br>
+                                  fs_seconds(max_seconds))<br>
         .count();<br>
<br>
-template <class FileTimeT><br>
-const long long fs_time_util_base<FileTimeT, true>::min_seconds =<br>
-    duration_cast<seconds>(<wbr>FileTimeT::duration::min()).<wbr>count();<br>
-<br>
-template <class FileTimeT><br>
-const long long fs_time_util_base<FileTimeT, true>::min_nsec_timespec =<br>
-    duration_cast<nanoseconds>(<br>
-        (FileTimeT::duration::min() - seconds(min_seconds)) + seconds(1))<br>
-        .count();<br>
+template <class FileTimeT, class TimeT><br>
+const typename FileTimeT::rep<br>
+    time_util_base<FileTimeT, TimeT, true>::min_seconds =<br>
+        duration_cast<fs_seconds>(<wbr>FileTimeT::duration::min()).<wbr>count();<br>
+<br>
+template <class FileTimeT, class TimeT><br>
+const typename FileTimeT::rep<br>
+    time_util_base<FileTimeT, TimeT, true>::min_nsec_timespec =<br>
+        duration_cast<fs_nanoseconds>(<wbr>(FileTimeT::duration::min() -<br>
+                                       fs_seconds(min_seconds)) +<br>
+                                      fs_seconds(1))<br>
+            .count();<br>
<br>
 template <class FileTimeT, class TimeT, class TimeSpecT><br>
-struct fs_time_util : fs_time_util_base<FileTimeT> {<br>
-  using Base = fs_time_util_base<FileTimeT>;<br>
+struct time_util : time_util_base<FileTimeT, TimeT> {<br>
+  using Base = time_util_base<FileTimeT, TimeT>;<br>
   using Base::max_nsec;<br>
   using Base::max_seconds;<br>
   using Base::min_nsec_timespec;<br>
   using Base::min_seconds;<br>
<br>
+  using typename Base::fs_duration;<br>
+  using typename Base::fs_microseconds;<br>
+  using typename Base::fs_nanoseconds;<br>
+  using typename Base::fs_seconds;<br>
+<br>
 public:<br>
   template <class CType, class ChronoType><br>
-  static bool checked_set(CType* out, ChronoType time) {<br>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool checked_set(CType* out,<br>
+                                                        ChronoType time) {<br>
     using Lim = numeric_limits<CType>;<br>
     if (time > Lim::max() || time < Lim::min())<br>
       return false;<br>
@@ -291,21 +318,21 @@ public:<br>
<br>
   static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(TimeSpecT tm) {<br>
     if (tm.tv_sec >= 0) {<br>
-      return (tm.tv_sec < max_seconds) ||<br>
+      return tm.tv_sec < max_seconds ||<br>
              (tm.tv_sec == max_seconds && tm.tv_nsec <= max_nsec);<br>
     } else if (tm.tv_sec == (min_seconds - 1)) {<br>
       return tm.tv_nsec >= min_nsec_timespec;<br>
     } else {<br>
-      return (tm.tv_sec >= min_seconds);<br>
+      return tm.tv_sec >= min_seconds;<br>
     }<br>
   }<br>
<br>
   static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(FileTimeT tm) {<br>
-    auto secs = duration_cast<seconds>(tm.<wbr>time_since_epoch());<br>
-    auto nsecs = duration_cast<nanoseconds>(tm.<wbr>time_since_epoch() - secs);<br>
+    auto secs = duration_cast<fs_seconds>(tm.<wbr>time_since_epoch());<br>
+    auto nsecs = duration_cast<fs_nanoseconds>(<wbr>tm.time_since_epoch() - secs);<br>
     if (nsecs.count() < 0) {<br>
-      secs = secs + seconds(1);<br>
-      nsecs = nsecs + seconds(1);<br>
+      secs = secs + fs_seconds(1);<br>
+      nsecs = nsecs + fs_seconds(1);<br>
     }<br>
     using TLim = numeric_limits<TimeT>;<br>
     if (secs.count() >= 0)<br>
@@ -314,49 +341,45 @@ public:<br>
   }<br>
<br>
   static _LIBCPP_CONSTEXPR_AFTER_CXX11 FileTimeT<br>
-  convert_timespec(TimeSpecT tm) {<br>
-    auto adj_msec = duration_cast<microseconds>(<wbr>nanoseconds(tm.tv_nsec));<br>
-    if (tm.tv_sec >= 0) {<br>
-      auto Dur = seconds(tm.tv_sec) + microseconds(adj_msec);<br>
-      return FileTimeT(Dur);<br>
-    } else if (duration_cast<microseconds>(<wbr>nanoseconds(tm.tv_nsec)).<wbr>count() ==<br>
-               0) {<br>
-      return FileTimeT(seconds(tm.tv_sec));<br>
+  convert_from_timespec(<wbr>TimeSpecT tm) {<br>
+    if (tm.tv_sec >= 0 || tm.tv_nsec == 0) {<br>
+      return FileTimeT(fs_seconds(tm.tv_<wbr>sec) +<br>
+                       duration_cast<fs_duration>(<wbr>fs_nanoseconds(tm.tv_nsec)));<br>
     } else { // tm.tv_sec < 0<br>
-      auto adj_subsec =<br>
-          duration_cast<microseconds>(<wbr>seconds(1) - nanoseconds(tm.tv_nsec));<br>
-      auto Dur = seconds(tm.tv_sec + 1) - adj_subsec;<br>
+      auto adj_subsec = duration_cast<fs_duration>(fs_<wbr>seconds(1) -<br>
+                                                   fs_nanoseconds(tm.tv_nsec));<br>
+      auto Dur = fs_seconds(tm.tv_sec + 1) - adj_subsec;<br>
       return FileTimeT(Dur);<br>
     }<br>
   }<br>
<br>
-  template <class SubSecDurT, class SubSecT><br>
-  static bool set_times_checked(TimeT* sec_out, SubSecT* subsec_out,<br>
-                                FileTimeT tp) {<br>
+  template <class SubSecT><br>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool<br>
+  set_times_checked(TimeT* sec_out, SubSecT* subsec_out, FileTimeT tp) {<br>
     auto dur = tp.time_since_epoch();<br>
-    auto sec_dur = duration_cast<seconds>(dur);<br>
-    auto subsec_dur = duration_cast<SubSecDurT>(dur - sec_dur);<br>
+    auto sec_dur = duration_cast<fs_seconds>(dur)<wbr>;<br>
+    auto subsec_dur = duration_cast<fs_nanoseconds>(<wbr>dur - sec_dur);<br>
     // The tv_nsec and tv_usec fields must not be negative so adjust accordingly<br>
     if (subsec_dur.count() < 0) {<br>
       if (sec_dur.count() > min_seconds) {<br>
-        sec_dur -= seconds(1);<br>
-        subsec_dur += seconds(1);<br>
+        sec_dur -= fs_seconds(1);<br>
+        subsec_dur += fs_seconds(1);<br>
       } else {<br>
-        subsec_dur = SubSecDurT::zero();<br>
+        subsec_dur = fs_nanoseconds::zero();<br>
       }<br>
     }<br>
     return checked_set(sec_out, sec_dur.count()) &&<br>
            checked_set(subsec_out, subsec_dur.count());<br>
   }<br>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool convert_to_timespec(TimeSpecT& dest,<br>
+                                                                FileTimeT tp) {<br>
+    if (!is_representable(tp))<br>
+      return false;<br>
+    return set_times_checked(&dest.tv_<wbr>sec, &dest.tv_nsec, tp);<br>
+  }<br>
 };<br>
<br>
-} // namespace time_util<br>
-<br>
-<br>
-using TimeSpec = struct ::timespec;<br>
-using StatT = struct ::stat;<br>
-<br>
-using FSTime = time_util::fs_time_util<file_<wbr>time_type, time_t, struct timespec>;<br>
+using fs_time = time_util<file_time_type, time_t, TimeSpec>;<br>
<br>
 #if defined(__APPLE__)<br>
 TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }<br>
@@ -366,20 +389,18 @@ TimeSpec extract_mtime(StatT const& st)<br>
 TimeSpec extract_atime(StatT const& st) { return st.st_atim; }<br>
 #endif<br>
<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
-using TimeStruct = struct ::timeval;<br>
-using TimeStructArray = TimeStruct[2];<br>
-#else<br>
-using TimeStruct = TimeSpec;<br>
-using TimeStructArray = TimeStruct[2];<br>
-#endif<br>
-<br>
-bool SetFileTimes(const path& p, TimeStructArray const& TS,<br>
-                  error_code& ec) {<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
-  if (::utimes(p.c_str(), TS) == -1)<br>
+bool set_file_times(const path& p, std::array<TimeSpec, 2> const& TS,<br>
+                    error_code& ec) {<br>
+#if !defined(_LIBCPP_USE_<wbr>UTIMENSAT)<br>
+  using namespace chrono;<br>
+  auto Convert = [](long nsec) {<br>
+    return duration_cast<microseconds>(<wbr>nanoseconds(nsec)).count();<br>
+  };<br>
+  struct ::timeval ConvertedTS[2] = {{TS[0].tv_sec, Convert(TS[0].tv_nsec)},<br>
+                                     {TS[1].tv_sec, Convert(TS[1].tv_nsec)}};<br></blockquote><div><br></div><div>This causes the '-Wc++11-narrowing' warning on Darwin:</div><div><br></div><div><span style="color:rgb(51,51,51);font-family:monospace;font-size:15px;white-space:pre-wrap">filesystem_common.h:399:53: error: non-constant-expression cannot be narrowed from type 'long long' to '__darwin_suseconds_t' (aka 'int') in initializer list [-Wc++11-narrowing]
  struct ::timeval ConvertedTS[2] = {{TS[0].tv_sec, Convert(TS[0].tv_nsec)},
                                                    ^~~~~~~~~~~~~~~~~~~~~~</span><br></div><div><font color="#333333" face="monospace"><span style="font-size:15px;white-space:pre-wrap">I'll work on a fix commit.</span></font></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
+  if (::utimes(p.c_str(), ConvertedTS) == -1)<br>
 #else<br>
-  if (::utimensat(AT_FDCWD, p.c_str(), TS, 0) == -1)<br>
+  if (::utimensat(AT_FDCWD, p.c_str(), TS.data(), 0) == -1)<br>
 #endif<br>
   {<br>
     ec = capture_errno();<br>
@@ -388,25 +409,9 @@ bool SetFileTimes(const path& p, TimeStr<br>
   return false;<br>
 }<br>
<br>
-void SetTimeStructTo(TimeStruct& TS, TimeSpec ToTS) {<br>
-  using namespace chrono;<br>
-  TS.tv_sec = ToTS.tv_sec;<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
-  TS.tv_usec = duration_cast<microseconds>(<wbr>nanoseconds(ToTS.tv_nsec)).<wbr>count();<br>
-#else<br>
-  TS.tv_nsec = ToTS.tv_nsec;<br>
-#endif<br>
-}<br>
-<br>
-bool SetTimeStructTo(TimeStruct& TS, file_time_type NewTime) {<br>
-  using namespace chrono;<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
-  return !FSTime::set_times_checked<<wbr>microseconds>(&TS.tv_sec, &TS.tv_usec,<br>
-                                                  NewTime);<br>
-#else<br>
-  return !FSTime::set_times_checked<<wbr>nanoseconds>(&TS.tv_sec, &TS.tv_nsec,<br>
-                                                 NewTime);<br>
-#endif<br>
+bool set_time_spec_to(TimeSpec& TS, file_time_type NewTime) {<br>
+  return !fs_time::set_times_checked(<br>
+      &TS.tv_sec, &TS.tv_nsec, NewTime);<br>
 }<br>
<br>
 } // namespace<br>
<br>
Modified: libcxx/trunk/src/experimental/<wbr>filesystem/operations.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/experimental/filesystem/operations.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/src/<wbr>experimental/filesystem/<wbr>operations.cpp?rev=337960&r1=<wbr>337959&r2=337960&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/src/experimental/<wbr>filesystem/operations.cpp (original)<br>
+++ libcxx/trunk/src/experimental/<wbr>filesystem/operations.cpp Wed Jul 25 13:51:49 2018<br>
@@ -23,6 +23,7 @@<br>
 #include <unistd.h><br>
 #include <sys/stat.h><br>
 #include <sys/statvfs.h><br>
+#include <time.h><br>
 #include <fcntl.h>  /* values for fchmodat */<br>
<br>
 #if defined(__linux__)<br>
@@ -36,6 +37,14 @@<br>
 # define _LIBCPP_USE_COPYFILE<br>
 #endif<br>
<br>
+#if !defined(__APPLE__)<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
+#endif<br>
+<br>
+#if !defined(CLOCK_REALTIME) || !defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME)<br>
+#include <sys/time.h> // for gettimeofday and timeval<br>
+#endif                // !defined(CLOCK_REALTIME)<br>
+<br>
 #if defined(_LIBCPP_COMPILER_GCC)<br>
 #if _GNUC_VER < 500<br>
 #pragma GCC diagnostic ignored "-Wmissing-field-initializers"<br>
@@ -44,9 +53,6 @@<br>
<br>
 _LIBCPP_BEGIN_NAMESPACE_<wbr>EXPERIMENTAL_FILESYSTEM<br>
<br>
-filesystem_error::~<wbr>filesystem_error() {}<br>
-<br>
-<br>
 namespace { namespace parser<br>
 {<br>
<br>
@@ -355,7 +361,7 @@ private:<br>
   explicit FileDescriptor(const path* p, int fd = -1) : name(*p), fd(fd) {}<br>
 };<br>
<br>
-perms posix_get_perms(const struct ::stat& st) noexcept {<br>
+perms posix_get_perms(const StatT& st) noexcept {<br>
   return static_cast<perms>(st.st_mode) & perms::mask;<br>
 }<br>
<br>
@@ -364,8 +370,7 @@ perms posix_get_perms(const struct ::sta<br>
 }<br>
<br>
 file_status create_file_status(error_code& m_ec, path const& p,<br>
-                               const struct ::stat& path_stat,<br>
-                               error_code* ec) {<br>
+                               const StatT& path_stat, error_code* ec) {<br>
   if (ec)<br>
     *ec = m_ec;<br>
   if (m_ec && (m_ec.value() == ENOENT || m_ec.value() == ENOTDIR)) {<br>
@@ -400,8 +405,7 @@ file_status create_file_status(error_cod<br>
   return fs_tmp;<br>
 }<br>
<br>
-file_status posix_stat(path const& p, struct ::stat& path_stat,<br>
-                       error_code* ec) {<br>
+file_status posix_stat(path const& p, StatT& path_stat, error_code* ec) {<br>
   error_code m_ec;<br>
   if (::stat(p.c_str(), &path_stat) == -1)<br>
     m_ec = detail::capture_errno();<br>
@@ -409,12 +413,11 @@ file_status posix_stat(path const& p, st<br>
 }<br>
<br>
 file_status posix_stat(path const& p, error_code* ec) {<br>
-  struct ::stat path_stat;<br>
+  StatT path_stat;<br>
   return posix_stat(p, path_stat, ec);<br>
 }<br>
<br>
-file_status posix_lstat(path const& p, struct ::stat& path_stat,<br>
-                        error_code* ec) {<br>
+file_status posix_lstat(path const& p, StatT& path_stat, error_code* ec) {<br>
   error_code m_ec;<br>
   if (::lstat(p.c_str(), &path_stat) == -1)<br>
     m_ec = detail::capture_errno();<br>
@@ -422,7 +425,7 @@ file_status posix_lstat(path const& p, s<br>
 }<br>
<br>
 file_status posix_lstat(path const& p, error_code* ec) {<br>
-  struct ::stat path_stat;<br>
+  StatT path_stat;<br>
   return posix_lstat(p, path_stat, ec);<br>
 }<br>
<br>
@@ -464,10 +467,32 @@ file_status FileDescriptor::refresh_stat<br>
 using detail::capture_errno;<br>
 using detail::ErrorHandler;<br>
 using detail::StatT;<br>
+using detail::TimeSpec;<br>
 using parser::createView;<br>
 using parser::PathParser;<br>
 using parser::string_view_t;<br>
<br>
+const bool _FilesystemClock::is_steady;<br>
+<br>
+_FilesystemClock::time_point _FilesystemClock::now() noexcept {<br>
+  typedef chrono::duration<rep> __secs;<br>
+#if defined(_LIBCPP_USE_CLOCK_<wbr>GETTIME) && defined(CLOCK_REALTIME)<br>
+  typedef chrono::duration<rep, nano> __nsecs;<br>
+  struct timespec tp;<br>
+  if (0 != clock_gettime(CLOCK_REALTIME, &tp))<br>
+    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");<br>
+  return time_point(__secs(tp.tv_sec) +<br>
+                    chrono::duration_cast<<wbr>duration>(__nsecs(tp.tv_nsec))<wbr>);<br>
+#else<br>
+  typedef chrono::duration<rep, micro> __microsecs;<br>
+  timeval tv;<br>
+  gettimeofday(&tv, 0);<br>
+  return time_point(__secs(tv.tv_sec) + __microsecs(tv.tv_usec));<br>
+#endif // _LIBCPP_USE_CLOCK_GETTIME && CLOCK_REALTIME<br>
+}<br>
+<br>
+filesystem_error::~<wbr>filesystem_error() {}<br>
+<br>
 void filesystem_error::__create_<wbr>what(int __num_paths) {<br>
   const char* derived_what = system_error::what();<br>
   __storage_->__what_ = [&]() -> string {<br>
@@ -525,14 +550,14 @@ void __copy(const path& from, const path<br>
   const bool sym_status2 = bool(options & copy_options::copy_symlinks);<br>
<br>
   error_code m_ec1;<br>
-  struct ::stat f_st = {};<br>
+  StatT f_st = {};<br>
   const file_status f = sym_status || sym_status2<br>
                             ? detail::posix_lstat(from, f_st, &m_ec1)<br>
                             : detail::posix_stat(from, f_st, &m_ec1);<br>
   if (m_ec1)<br>
     return err.report(m_ec1);<br>
<br>
-  struct ::stat t_st = {};<br>
+  StatT t_st = {};<br>
   const file_status t = sym_status ? detail::posix_lstat(to, t_st, &m_ec1)<br>
                                    : detail::posix_stat(to, t_st, &m_ec1);<br>
<br>
@@ -916,7 +941,7 @@ uintmax_t __file_size(const path& p, err<br>
   ErrorHandler<uintmax_t> err("file_size", ec, &p);<br>
<br>
   error_code m_ec;<br>
-  struct ::stat st;<br>
+  StatT st;<br>
   file_status fst = detail::posix_stat(p, st, &m_ec);<br>
   if (!exists(fst) || !is_regular_file(fst)) {<br>
     errc error_kind =<br>
@@ -966,14 +991,14 @@ bool __fs_is_empty(const path& p, error_<br>
<br>
 static file_time_type __extract_last_write_time(<wbr>const path& p, const StatT& st,<br>
                                                 error_code* ec) {<br>
-  using detail::FSTime;<br>
+  using detail::fs_time;<br>
   ErrorHandler<file_time_type> err("last_write_time", ec, &p);<br>
<br>
   auto ts = detail::extract_mtime(st);<br>
-  if (!FSTime::is_representable(ts)<wbr>)<br>
+  if (!fs_time::is_representable(<wbr>ts))<br>
     return err.report(errc::value_too_<wbr>large);<br>
<br>
-  return FSTime::convert_timespec(ts);<br>
+  return fs_time::convert_from_<wbr>timespec(ts);<br>
 }<br>
<br>
 file_time_type __last_write_time(const path& p, error_code *ec)<br>
@@ -992,30 +1017,27 @@ file_time_type __last_write_time(const p<br>
 void __last_write_time(const path& p, file_time_type new_time,<br>
                        error_code *ec)<br>
 {<br>
-    using namespace chrono;<br>
-    using namespace detail;<br>
-<br>
     ErrorHandler<void> err("last_write_time", ec, &p);<br>
<br>
     error_code m_ec;<br>
-    TimeStructArray tbuf;<br>
-#if !defined(_LIBCXX_USE_<wbr>UTIMENSAT)<br>
+    array<TimeSpec, 2> tbuf;<br>
+#if !defined(_LIBCPP_USE_<wbr>UTIMENSAT)<br>
     // This implementation has a race condition between determining the<br>
     // last access time and attempting to set it to the same value using<br>
     // ::utimes<br>
-    struct ::stat st;<br>
+    StatT st;<br>
     file_status fst = detail::posix_stat(p, st, &m_ec);<br>
-    if (m_ec && !status_known(fst))<br>
+    if (m_ec)<br>
       return err.report(m_ec);<br>
-    SetTimeStructTo(tbuf[0], detail::extract_atime(st));<br>
+    tbuf[0] = detail::extract_atime(st);<br>
 #else<br>
     tbuf[0].tv_sec = 0;<br>
     tbuf[0].tv_nsec = UTIME_OMIT;<br>
 #endif<br>
-    if (SetTimeStructTo(tbuf[1], new_time))<br>
-      return err.report(errc::invalid_<wbr>argument);<br>
+    if (detail::set_time_spec_to(<wbr>tbuf[1], new_time))<br>
+      return err.report(errc::value_too_<wbr>large);<br>
<br>
-    SetFileTimes(p, tbuf, m_ec);<br>
+    detail::set_file_times(p, tbuf, m_ec);<br>
     if (m_ec)<br>
       return err.report(m_ec);<br>
 }<br>
@@ -1591,7 +1613,7 @@ error_code directory_entry::__do_refresh<br>
   __data_.__reset();<br>
   error_code failure_ec;<br>
<br>
-  struct ::stat full_st;<br>
+  StatT full_st;<br>
   file_status st = detail::posix_lstat(__p_, full_st, &failure_ec);<br>
   if (!status_known(st)) {<br>
     __data_.__reset();<br>
<br>
Added: libcxx/trunk/src/include/<wbr>apple_availability.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/include/apple_availability.h?rev=337960&view=auto" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/src/<wbr>include/apple_availability.h?<wbr>rev=337960&view=auto</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/src/include/<wbr>apple_availability.h (added)<br>
+++ libcxx/trunk/src/include/<wbr>apple_availability.h Wed Jul 25 13:51:49 2018<br>
@@ -0,0 +1,52 @@<br>
+//===------------------------ apple_availability.h ------------------------===//<br>
+//<br>
+//                     The LLVM Compiler Infrastructure<br>
+//<br>
+// This file is dual licensed under the MIT and the University of Illinois Open<br>
+// Source Licenses. See LICENSE.TXT for details.<br>
+//<br>
+//===------------------------<wbr>------------------------------<wbr>----------------===//<br>
+#ifndef _LIBCPP_SRC_INCLUDE_APPLE_<wbr>AVAILABILITY_H<br>
+#define _LIBCPP_SRC_INCLUDE_APPLE_<wbr>AVAILABILITY_H<br>
+<br>
+#if defined(__APPLE__)<br>
+<br>
+#if defined(__ENVIRONMENT_MAC_OS_<wbr>X_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_MAC_OS_X_<wbr>VERSION_MIN_REQUIRED__ >= 101300<br>
+#define _LIBCPP_USE_UTIMENSAT<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_IPHONE_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_IPHONE_OS_<wbr>VERSION_MIN_REQUIRED__ >= 110000<br>
+#define _LIBCPP_USE_UTIMENSAT<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_TV_OS_<wbr>VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_TV_OS_VERSION_<wbr>MIN_REQUIRED__ >= 110000<br>
+#define _LIBCPP_USE_UTIMENSAT<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_WATCH_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_WATCH_OS_<wbr>VERSION_MIN_REQUIRED__ >= 40000<br>
+#define _LIBCPP_USE_UTIMENSAT<br>
+#endif<br>
+#endif // __ENVIRONMENT_.*_VERSION_MIN_<wbr>REQUIRED__<br>
+<br>
+#if defined(__ENVIRONMENT_MAC_OS_<wbr>X_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_MAC_OS_X_<wbr>VERSION_MIN_REQUIRED__ >= 101200<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_IPHONE_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_IPHONE_OS_<wbr>VERSION_MIN_REQUIRED__ >= 100000<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_TV_OS_<wbr>VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_TV_OS_VERSION_<wbr>MIN_REQUIRED__ >= 100000<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
+#endif<br>
+#elif defined(__ENVIRONMENT_WATCH_<wbr>OS_VERSION_MIN_REQUIRED__)<br>
+#if __ENVIRONMENT_WATCH_OS_<wbr>VERSION_MIN_REQUIRED__ >= 30000<br>
+#define _LIBCPP_USE_CLOCK_GETTIME<br>
+#endif<br>
+#endif // __ENVIRONMENT_.*_VERSION_MIN_<wbr>REQUIRED__<br>
+<br>
+#endif // __APPLE__<br>
+<br>
+#endif // _LIBCPP_SRC_INCLUDE_APPLE_<wbr>AVAILABILITY_H<br>
<br>
Modified: libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/class.<wbr>directory_entry/directory_<wbr>entry.mods/last_write_time.sh.<wbr>cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/experimental/filesystem/class.directory_entry/directory_entry.mods/last_write_time.sh.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/test/<wbr>libcxx/experimental/<wbr>filesystem/class.directory_<wbr>entry/directory_entry.mods/<wbr>last_write_time.sh.cpp?rev=<wbr>337960&r1=337959&r2=337960&<wbr>view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/class.<wbr>directory_entry/directory_<wbr>entry.mods/last_write_time.sh.<wbr>cpp (original)<br>
+++ libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/class.<wbr>directory_entry/directory_<wbr>entry.mods/last_write_time.sh.<wbr>cpp Wed Jul 25 13:51:49 2018<br>
@@ -41,9 +41,7 @@ TEST_CASE(last_write_time_not_<wbr>representa<br>
   ToTime.tv_sec = std::numeric_limits<decltype(<wbr>ToTime.tv_sec)>::max();<br>
   ToTime.tv_nsec = duration_cast<nanoseconds>(<wbr>seconds(1)).count() - 1;<br>
<br>
-  TimeStructArray TS;<br>
-  SetTimeStructTo(TS[0], ToTime);<br>
-  SetTimeStructTo(TS[1], ToTime);<br>
+  std::array<TimeSpec, 2> TS = {ToTime, ToTime};<br>
<br>
   file_time_type old_time = last_write_time(file);<br>
   directory_entry ent(file);<br>
@@ -57,9 +55,7 @@ TEST_CASE(last_write_time_not_<wbr>representa<br>
   file_time_type rep_value;<br>
   {<br>
     std::error_code ec;<br>
-    if (SetFileTimes(file, TS, ec)) {<br>
-      TEST_REQUIRE(false && "unsupported");<br>
-    }<br>
+    TEST_REQUIRE(!set_file_times(<wbr>file, TS, ec));<br>
     ec.clear();<br>
     rep_value = last_write_time(file, ec);<br>
     IsRepresentable = !bool(ec);<br>
@@ -82,7 +78,7 @@ TEST_CASE(last_write_time_not_<wbr>representa<br>
<br>
     ExceptionChecker CheckExcept(file, expected_err,<br>
                                  "directory_entry::last_write_<wbr>time");<br>
-    TEST_CHECK_THROW_RESULT(fs::<wbr>filesystem_error, CheckExcept,<br>
+    TEST_CHECK_THROW_RESULT(<wbr>filesystem_error, CheckExcept,<br>
                             ent.last_write_time());<br>
<br>
   } else {<br>
<br>
Modified: libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/<wbr>convert_file_time.sh.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/experimental/filesystem/convert_file_time.sh.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/test/<wbr>libcxx/experimental/<wbr>filesystem/convert_file_time.<wbr>sh.cpp?rev=337960&r1=337959&<wbr>r2=337960&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/<wbr>convert_file_time.sh.cpp (original)<br>
+++ libcxx/trunk/test/libcxx/<wbr>experimental/filesystem/<wbr>convert_file_time.sh.cpp Wed Jul 25 13:51:49 2018<br>
@@ -25,15 +25,23 @@<br>
<br>
 #include "filesystem_common.h"<br>
<br>
+#ifndef __SIZEOF_INT128__<br>
+#define TEST_HAS_NO_INT128_T<br>
+#endif<br>
+<br>
 using namespace std::chrono;<br>
 namespace fs = std::experimental::filesystem;<br>
 using fs::file_time_type;<br>
-using fs::detail::time_util::fs_<wbr>time_util;<br>
+using fs::detail::time_util;<br>
+<br>
+#ifdef TEST_HAS_NO_INT128_T<br>
+static_assert(sizeof(fs::<wbr>file_time_type::rep) <= 8, "");<br>
+#endif<br>
<br>
-enum TestKind { TK_64Bit, TK_32Bit, TK_FloatingPoint };<br>
+enum TestKind { TK_128Bit, TK_64Bit, TK_32Bit, TK_FloatingPoint };<br>
<br>
-template <class FileTimeT, class TimeT, class TimeSpec><br>
-constexpr TestKind getTestKind() {<br>
+template <class TimeT><br>
+constexpr TestKind getTimeTTestKind() {<br>
   if (sizeof(TimeT) == 8 && !std::is_floating_point<TimeT><wbr>::value)<br>
     return TK_64Bit;<br>
   else if (sizeof(TimeT) == 4 && !std::is_floating_point<TimeT><wbr>::value)<br>
@@ -43,17 +51,99 @@ constexpr TestKind getTestKind() {<br>
   else<br>
     assert(false && "test kind not supported");<br>
 }<br>
+template <class FileTimeT><br>
+constexpr TestKind getFileTimeTestKind() {<br>
+  using Rep = typename FileTimeT::rep;<br>
+  if (std::is_floating_point<Rep>::<wbr>value)<br>
+    return TK_FloatingPoint;<br>
+  if (sizeof(Rep) == 16)<br>
+    return TK_128Bit;<br>
+  if (sizeof(Rep) == 8)<br>
+    return TK_64Bit;<br>
+  assert(false && "test kind not supported");<br>
+}<br>
<br>
 template <class FileTimeT, class TimeT, class TimeSpecT,<br>
-          class Base = fs_time_util<FileTimeT, TimeT, TimeSpecT>,<br>
-          TestKind = getTestKind<FileTimeT, TimeT, TimeSpecT>()><br>
-struct check_is_representable;<br>
+          class Base = time_util<FileTimeT, TimeT, TimeSpecT>,<br>
+          TestKind = getTimeTTestKind<TimeT>(),<br>
+          TestKind = getFileTimeTestKind<FileTimeT><wbr>()><br>
+struct test_case;<br>
<br>
 template <class FileTimeT, class TimeT, class TimeSpecT, class Base><br>
-struct check_is_representable<<wbr>FileTimeT, TimeT, TimeSpecT, Base, TK_64Bit><br>
+struct test_case<FileTimeT, TimeT, TimeSpecT, Base, TK_64Bit, TK_128Bit><br>
     : public Base {<br>
<br>
-  using Base::convert_timespec;<br>
+  using Base::convert_from_timespec;<br>
+  using Base::convert_to_timespec;<br>
+  using Base::is_representable;<br>
+  using Base::max_nsec;<br>
+  using Base::max_seconds;<br>
+  using Base::min_nsec_timespec;<br>
+  using Base::min_seconds;<br>
+<br>
+  static constexpr auto max_time_t = std::numeric_limits<TimeT>::<wbr>max();<br>
+  static constexpr auto min_time_t = std::numeric_limits<TimeT>::<wbr>min();<br>
+<br>
+  static constexpr bool test_timespec() {<br>
+    static_assert(is_<wbr>representable(TimeSpecT{max_<wbr>time_t, 0}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{max_<wbr>time_t, 999999999}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{max_<wbr>time_t, 1000000000}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{max_<wbr>time_t, max_nsec}), "");<br>
+<br>
+    static_assert(is_<wbr>representable(TimeSpecT{min_<wbr>time_t, 0}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{min_<wbr>time_t, 999999999}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{min_<wbr>time_t, 1000000000}), "");<br>
+    static_assert(is_<wbr>representable(TimeSpecT{min_<wbr>time_t, min_nsec_timespec}),<br>
+                  "");<br>
+<br>
+    return true;<br>
+  }<br>
+<br>
+  static constexpr bool test_file_time_type() {<br>
+    // This kinda sucks. Oh well.<br>
+    static_assert(!Base::is_<wbr>representable(FileTimeT::max()<wbr>), "");<br>
+    static_assert(!Base::is_<wbr>representable(FileTimeT::min()<wbr>), "");<br>
+    return true;<br>
+  }<br>
+<br>
+  static constexpr bool check_round_trip(TimeSpecT orig) {<br>
+    TimeSpecT new_ts = {};<br>
+    FileTimeT out = convert_from_timespec(orig);<br>
+    assert(convert_to_timespec(<wbr>new_ts, out));<br>
+    return new_ts.tv_sec == orig.tv_sec && new_ts.tv_nsec == orig.tv_nsec;<br>
+  }<br>
+<br>
+  static constexpr bool test_convert_timespec() {<br>
+    static_assert(check_round_<wbr>trip({0, 0}), "");<br>
+    static_assert(check_round_<wbr>trip({0, 1}), "");<br>
+    static_assert(check_round_<wbr>trip({1, 1}), "");<br>
+    static_assert(check_round_<wbr>trip({-1, 1}), "");<br>
+    static_assert(check_round_<wbr>trip({max_time_t, max_nsec}), "");<br>
+    static_assert(check_round_<wbr>trip({max_time_t, 123}), "");<br>
+    static_assert(check_round_<wbr>trip({min_time_t, min_nsec_timespec}), "");<br>
+    static_assert(check_round_<wbr>trip({min_time_t, 123}), "");<br>
+    return true;<br>
+  }<br>
+<br>
+  static bool test() {<br>
+    static_assert(test_timespec(), "");<br>
+    static_assert(test_file_time_<wbr>type(), "");<br>
+    static_assert(test_convert_<wbr>timespec(), "");<br>
+    return true;<br>
+  }<br>
+};<br>
+<br>
+template <class FileTimeT, class TimeT, class TimeSpecT, class Base><br>
+struct test_case<FileTimeT, TimeT, TimeSpecT, Base, TK_32Bit, TK_128Bit><br>
+    : public test_case<FileTimeT, TimeT, TimeSpecT, Base, TK_64Bit, TK_128Bit> {<br>
+<br>
+};<br>
+<br>
+template <class FileTimeT, class TimeT, class TimeSpecT, class Base><br>
+struct test_case<FileTimeT, TimeT, TimeSpecT, Base, TK_64Bit, TK_64Bit><br>
+    : public Base {<br>
+<br>
+  using Base::convert_from_timespec;<br>
   using Base::is_representable;<br>
   using Base::max_nsec;<br>
   using Base::max_seconds;<br>
@@ -88,24 +178,25 @@ struct check_is_representable<<wbr>FileTimeT,<br>
   }<br>
<br>
   static constexpr bool test_convert_timespec() {<br>
-    static_assert(convert_<wbr>timespec(TimeSpecT{max_<wbr>seconds, max_nsec}) ==<br>
+    static_assert(convert_from_<wbr>timespec(TimeSpecT{max_<wbr>seconds, max_nsec}) ==<br>
                       FileTimeT::max(),<br>
                   "");<br>
-    static_assert(convert_<wbr>timespec(TimeSpecT{max_<wbr>seconds, max_nsec - 1}) <<br>
+    static_assert(convert_from_<wbr>timespec(TimeSpecT{max_<wbr>seconds, max_nsec - 1}) <<br>
                       FileTimeT::max(),<br>
                   "");<br>
-    static_assert(convert_<wbr>timespec(TimeSpecT{max_seconds - 1, 999999999}) <<br>
+    static_assert(convert_from_<wbr>timespec(TimeSpecT{max_seconds - 1, 999999999}) <<br>
                       FileTimeT::max(),<br>
                   "");<br>
-    static_assert(convert_<wbr>timespec(TimeSpecT{<br>
+    static_assert(convert_from_<wbr>timespec(TimeSpecT{<br>
                       min_seconds - 1, min_nsec_timespec}) == FileTimeT::min(),<br>
                   "");<br>
-    static_assert(<br>
-        convert_timespec(TimeSpecT{<wbr>min_seconds - 1, min_nsec_timespec + 1}) ><br>
-            FileTimeT::min(),<br>
-        "");<br>
-    static_assert(<br>
-        convert_timespec(TimeSpecT{<wbr>min_seconds, 0}) > FileTimeT::min(), "");<br>
+    static_assert(convert_from_<wbr>timespec(<br>
+                      TimeSpecT{min_seconds - 1, min_nsec_timespec + 1}) ><br>
+                      FileTimeT::min(),<br>
+                  "");<br>
+    static_assert(convert_from_<wbr>timespec(TimeSpecT{min_<wbr>seconds, 0}) ><br>
+                      FileTimeT::min(),<br>
+                  "");<br>
     return true;<br>
   }<br>
<br>
@@ -118,12 +209,12 @@ struct check_is_representable<<wbr>FileTimeT,<br>
 };<br>
<br>
 template <class FileTimeT, class TimeT, class TimeSpecT, class Base><br>
-struct check_is_representable<<wbr>FileTimeT, TimeT, TimeSpecT, Base, TK_32Bit><br>
+struct test_case<FileTimeT, TimeT, TimeSpecT, Base, TK_32Bit, TK_64Bit><br>
     : public Base {<br>
   static constexpr auto max_time_t = std::numeric_limits<TimeT>::<wbr>max();<br>
   static constexpr auto min_time_t = std::numeric_limits<TimeT>::<wbr>min();<br>
<br>
-  using Base::convert_timespec;<br>
+  using Base::convert_from_timespec;<br>
   using Base::is_representable;<br>
   using Base::max_nsec;<br>
   using Base::max_seconds;<br>
@@ -158,9 +249,10 @@ struct check_is_representable<<wbr>FileTimeT,<br>
   }<br>
 };<br>
<br>
-template <class FileTimeT, class TimeT, class TimeSpec, class Base><br>
-struct check_is_representable<<wbr>FileTimeT, TimeT, TimeSpec, Base,<br>
-                              TK_FloatingPoint> : public Base {<br>
+template <class FileTimeT, class TimeT, class TimeSpec, class Base,<br>
+          TestKind FileTimeTKind><br>
+struct test_case<FileTimeT, TimeT, TimeSpec, Base, TK_FloatingPoint,<br>
+                 FileTimeTKind> : public Base {<br>
<br>
   static bool test() { return true; }<br>
 };<br>
@@ -182,19 +274,33 @@ struct TestClock {<br>
   static time_point now() noexcept { return {}; }<br>
 };<br>
<br>
-template <class IntType, class Dur = duration<IntType, std::micro> ><br>
-using TestFileTimeT = time_point<TestClock<Dur> >;<br>
+template <class IntType, class Period = std::micro><br>
+using TestFileTimeT = time_point<TestClock<duration<<wbr>IntType, Period> > >;<br>
<br>
 int main() {<br>
-  assert((<br>
-      check_is_representable<file_<wbr>time_type, time_t, struct timespec>::test()));<br>
-  assert((check_is_<wbr>representable<TestFileTimeT<<wbr>int64_t>, int64_t,<br>
-                                 TestTimeSpec<int64_t, long> >::test()));<br>
-  assert((check_is_<wbr>representable<TestFileTimeT<<wbr>long long>, int32_t,<br>
-                                 TestTimeSpec<int32_t, int32_t> >::test()));<br>
-<br>
-  // Test that insane platforms like ppc64 linux, which use long double as time_t,<br>
-  // at least compile.<br>
-  assert((check_is_<wbr>representable<TestFileTimeT<<wbr>long double>, double,<br>
-                                 TestTimeSpec<long double, long> >::test()));<br>
+  { assert((test_case<file_time_<wbr>type, time_t, struct timespec>::test())); }<br>
+  {<br>
+    assert((test_case<<wbr>TestFileTimeT<int64_t>, int64_t,<br>
+                      TestTimeSpec<int64_t, long> >::test()));<br>
+  }<br>
+  {<br>
+    assert((test_case<<wbr>TestFileTimeT<long long>, int32_t,<br>
+                      TestTimeSpec<int32_t, int32_t> >::test()));<br>
+  }<br>
+  {<br>
+    // Test that insane platforms like ppc64 linux, which use long double as time_t,<br>
+    // at least compile.<br>
+    assert((test_case<<wbr>TestFileTimeT<long double>, double,<br>
+                      TestTimeSpec<long double, long> >::test()));<br>
+  }<br>
+#ifndef TEST_HAS_NO_INT128_T<br>
+  {<br>
+    assert((test_case<<wbr>TestFileTimeT<__int128_t, std::nano>, int64_t,<br>
+                      TestTimeSpec<int64_t, long> >::test()));<br>
+  }<br>
+  {<br>
+    assert((test_case<<wbr>TestFileTimeT<__int128_t, std::nano>, int32_t,<br>
+                      TestTimeSpec<int32_t, int32_t> >::test()));<br>
+  }<br>
+#endif<br>
 }<br>
<br>
Modified: libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.<wbr>filesystem.synopsis/file_time_<wbr>type.pass.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/filesystem/fs.filesystem.synopsis/file_time_type.pass.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.<wbr>filesystem.synopsis/file_time_<wbr>type.pass.cpp?rev=337960&r1=<wbr>337959&r2=337960&view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.<wbr>filesystem.synopsis/file_time_<wbr>type.pass.cpp (original)<br>
+++ libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.<wbr>filesystem.synopsis/file_time_<wbr>type.pass.cpp Wed Jul 25 13:51:49 2018<br>
@@ -17,15 +17,30 @@<br>
 #include <chrono><br>
 #include <type_traits><br>
<br>
+#include "test_macros.h"<br>
+<br>
 // system_clock is used because it meets the requirements of TrivialClock,<br>
 // and the resolution and range of system_clock should match the operating<br>
 // system's file time type.<br>
-typedef std::chrono::system_clock              ExpectedClock;<br>
-typedef std::chrono::time_point<<wbr>ExpectedClock> ExpectedTimePoint;<br>
+<br>
+void test_trivial_clock() {<br>
+  using namespace fs;<br>
+  using Clock = file_time_type::clock;<br>
+  ASSERT_NOEXCEPT(Clock::now());<br>
+  ASSERT_SAME_TYPE(decltype(<wbr>Clock::now()), file_time_type);<br>
+  ASSERT_SAME_TYPE(Clock::time_<wbr>point, file_time_type);<br>
+  volatile auto* odr_use = &Clock::is_steady;<br>
+  ((void)odr_use);<br>
+}<br>
+<br>
+void test_time_point_resolution_<wbr>and_range() {<br>
+  using namespace fs;<br>
+  using Dur = file_time_type::duration;<br>
+  using Period = Dur::period;<br>
+  ASSERT_SAME_TYPE(Period, std::nano);<br>
+}<br>
<br>
 int main() {<br>
-  static_assert(std::is_same<<br>
-          fs::file_time_type,<br>
-          ExpectedTimePoint<br>
-      >::value, "");<br>
+  test_trivial_clock();<br>
+  test_time_point_resolution_<wbr>and_range();<br>
 }<br>
<br>
Modified: libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.op.<wbr>funcs/fs.op.last_write_time/<wbr>last_write_time.pass.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/filesystem/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp?rev=337960&r1=337959&r2=337960&view=diff" rel="noreferrer noreferrer" target="_blank">http://llvm.org/viewvc/llvm-<wbr>project/libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.op.<wbr>funcs/fs.op.last_write_time/<wbr>last_write_time.pass.cpp?rev=<wbr>337960&r1=337959&r2=337960&<wbr>view=diff</a><br>
==============================<wbr>==============================<wbr>==================<br>
--- libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.op.<wbr>funcs/fs.op.last_write_time/<wbr>last_write_time.pass.cpp (original)<br>
+++ libcxx/trunk/test/std/<wbr>experimental/filesystem/fs.op.<wbr>funcs/fs.op.last_write_time/<wbr>last_write_time.pass.cpp Wed Jul 25 13:51:49 2018<br>
@@ -30,13 +30,86 @@<br>
 #include <sys/stat.h><br>
 #include <iostream><br>
<br>
+#include <fcntl.h><br>
+#include <sys/time.h><br>
+<br>
 using namespace fs;<br>
<br>
-struct Times { std::time_t access, write; };<br>
+using TimeSpec = struct ::timespec;<br>
+using StatT = struct ::stat;<br>
+<br>
+using Sec = std::chrono::duration<file_<wbr>time_type::rep>;<br>
+using Hours = std::chrono::hours;<br>
+using Minutes = std::chrono::minutes;<br>
+using MicroSec = std::chrono::duration<file_<wbr>time_type::rep, std::micro>;<br>
+using NanoSec = std::chrono::duration<file_<wbr>time_type::rep, std::nano>;<br>
+using std::chrono::duration_cast;<br>
+<br>
+#if defined(__APPLE__)<br>
+TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }<br>
+TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; }<br>
+#else<br>
+TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; }<br>
+TimeSpec extract_atime(StatT const& st) { return st.st_atim; }<br>
+#endif<br>
+<br>
+bool ConvertToTimeSpec(TimeSpec& ts, file_time_type ft) {<br>
+  using SecFieldT = decltype(TimeSpec::tv_sec);<br>
+  using NSecFieldT = decltype(TimeSpec::tv_nsec);<br>
+  using SecLim = std::numeric_limits<SecFieldT><wbr>;<br>
+  using NSecLim = std::numeric_limits<<wbr>NSecFieldT>;<br>
+<br>
+  auto secs = duration_cast<Sec>(ft.time_<wbr>since_epoch());<br>
+  auto nsecs = duration_cast<NanoSec>(ft.<wbr>time_since_epoch() - secs);<br>
+  if (nsecs.count() < 0) {<br>
+    if (Sec::min().count() > SecLim::min()) {<br>
+      secs += Sec(1);<br>
+      nsecs -= Sec(1);<br>
+    } else {<br>
+      nsecs = NanoSec(0);<br>
+    }<br>
+  }<br>
+  if (SecLim::max() < secs.count() || SecLim::min() > secs.count())<br>
+    return false;<br>
+  if (NSecLim::max() < nsecs.count() || NSecLim::min() > nsecs.count())<br>
+    return false;<br>
+  ts.tv_sec = secs.count();<br>
+  ts.tv_nsec = nsecs.count();<br>
+  return true;<br>
+}<br>
+<br>
+bool ConvertFromTimeSpec(file_time_<wbr>type& ft, TimeSpec ts) {<br>
+  auto secs_part = duration_cast<file_time_type::<wbr>duration>(Sec(ts.tv_sec));<br>
+  if (duration_cast<Sec>(secs_part)<wbr>.count() != ts.tv_sec)<br>
+    return false;<br>
+  auto subsecs = duration_cast<file_time_type::<wbr>duration>(NanoSec(ts.tv_nsec))<wbr>;<br>
+  auto dur = secs_part + subsecs;<br>
+  if (dur < secs_part && subsecs.count() >= 0)<br>
+    return false;<br>
+  ft = file_time_type(dur);<br>
+  return true;<br>
+}<br>
+<br>
+bool CompareTimeExact(TimeSpec ts, TimeSpec ts2) {<br>
+  return ts2.tv_sec == ts.tv_sec && ts2.tv_nsec == ts.tv_nsec;<br>
+}<br>
+bool CompareTimeExact(file_time_<wbr>type ft, TimeSpec ts) {<br>
+  TimeSpec ts2 = {};<br>
+  if (!ConvertToTimeSpec(ts2, ft))<br>
+    return false;<br>
+  return CompareTimeExact(ts, ts2);<br>
+}<br>
+bool CompareTimeExact(TimeSpec ts, file_time_type ft) {<br>
+  return CompareTimeExact(ft, ts);<br>
+}<br>
+<br>
+struct Times {<br>
+  TimeSpec access, write;<br>
+};<br>
<br>
 Times GetTimes(path const& p) {<br>
     using Clock = file_time_type::clock;<br>
-    struct ::stat st;<br>
+    StatT st;<br>
     if (::stat(p.c_str(), &st) == -1) {<br>
         std::error_code ec(errno, std::generic_category());<br>
 #ifndef TEST_HAS_NO_EXCEPTIONS<br>
@@ -46,22 +119,18 @@ Times GetTimes(path const& p) {<br>
         std::exit(EXIT_FAILURE);<br>
 #endif<br>
     }<br>
-    return {st.st_atime, st.st_mtime};<br>
+    return {extract_atime(st), extract_mtime(st)};<br>
 }<br>
<br>
-std::time_t LastAccessTime(path const& p) {<br>
-    return GetTimes(p).access;<br>
-}<br>
+TimeSpec LastAccessTime(path const& p) { return GetTimes(p).access; }<br>
<br>
-std::time_t LastWriteTime(path const& p) {<br>
-    return GetTimes(p).write;<br>
-}<br>
+TimeSpec LastWriteTime(path const& p) { return GetTimes(p).write; }<br>
<br>
-std::pair<std::time_t, std::time_t> GetSymlinkTimes(path const& p) {<br>
-    using Clock = file_time_type::clock;<br>
-    struct ::stat st;<br>
-    if (::lstat(p.c_str(), &st) == -1) {<br>
-        std::error_code ec(errno, std::generic_category());<br>
+std::pair<TimeSpec, TimeSpec> GetSymlinkTimes(path const& p) {<br>
+  using Clock = file_time_type::clock;<br>
+  StatT st;<br>
+  if (::lstat(p.c_str(), &st) == -1) {<br>
+    std::error_code ec(errno, std::generic_category());<br>
 #ifndef TEST_HAS_NO_EXCEPTIONS<br>
         throw ec;<br>
 #else<br>
@@ -69,24 +138,10 @@ std::pair<std::time_t, std::time_t> GetS<br>
         std::exit(EXIT_FAILURE);<br>
 #endif<br>
     }<br>
-    return {st.st_atime, st.st_mtime};<br>
+    return {extract_atime(st), extract_mtime(st)};<br>
 }<br>
<br>
 namespace {<br>
-bool TestSupportsNegativeTimes() {<br>
-    using namespace std::chrono;<br>
-    std::error_code ec;<br>
-    std::time_t old_write_time, new_write_time;<br>
-    { // WARNING: Do not assert in this scope.<br>
-        scoped_test_env env;<br>
-        const path file = env.create_file("file", 42);<br>
-        old_write_time = LastWriteTime(file);<br>
-        file_time_type tp(seconds(-5));<br>
-        fs::last_write_time(file, tp, ec);<br>
-        new_write_time = LastWriteTime(file);<br>
-    }<br>
-    return !ec && new_write_time <= -5;<br>
-}<br>
<br>
 // In some configurations, the comparison is tautological and the test is valid.<br>
 // We disable the warning so that we can actually test it regardless. Also, that<br>
@@ -98,61 +153,131 @@ bool TestSupportsNegativeTimes() {<br>
 #pragma clang diagnostic ignored "-Wtautological-constant-<wbr>compare"<br>
 #endif<br>
<br>
-bool TestSupportsMaxTime() {<br>
-    using namespace std::chrono;<br>
-    using Lim = std::numeric_limits<std::time_<wbr>t>;<br>
-    auto max_sec = duration_cast<seconds>(file_<wbr>time_type::max().time_since_<wbr>epoch()).count();<br>
-    if (max_sec > Lim::max()) return false;<br>
-    std::error_code ec;<br>
-    std::time_t old_write_time, new_write_time;<br>
-    { // WARNING: Do not assert in this scope.<br>
-        scoped_test_env env;<br>
-        const path file = env.create_file("file", 42);<br>
-        old_write_time = LastWriteTime(file);<br>
-        file_time_type tp = file_time_type::max();<br>
-        fs::last_write_time(file, tp, ec);<br>
-        new_write_time = LastWriteTime(file);<br>
-    }<br>
-    return !ec && new_write_time > max_sec - 1;<br>
-}<br>
-<br>
-bool TestSupportsMinTime() {<br>
-    using namespace std::chrono;<br>
-    using Lim = std::numeric_limits<std::time_<wbr>t>;<br>
-    auto min_sec = duration_cast<seconds>(file_<wbr>time_type::min().time_since_<wbr>epoch()).count();<br>
-    if (min_sec < Lim::min()) return false;<br>
-    std::error_code ec;<br>
-    std::time_t old_write_time, new_write_time;<br>
-    { // WARNING: Do not assert in this scope.<br>
-      scoped_test_env env;<br>
-      const path file = env.create_file("file", 42);<br>
-      old_write_time = LastWriteTime(file);<br>
-      file_time_type tp = file_time_type::min();<br>
-      fs::last_write_time(file, tp, ec);<br>
-      new_write_time = LastWriteTime(file);<br>
-    }<br>
-    return !ec && new_write_time < min_sec + 1;<br>
-}<br>
-<br>
-#if defined(__clang__)<br>
-#pragma clang diagnostic pop<br>
-#endif<br>
-<br>
-static const bool SupportsNegativeTimes = TestSupportsNegativeTimes();<br>
-static const bool SupportsMaxTime = TestSupportsMaxTime();<br>
-static const bool SupportsMinTime = TestSupportsMinTime();<br>
+static const bool SupportsNegativeTimes = [] {<br>
+  using namespace std::chrono;<br>
+  std::error_code ec;<br>
+  TimeSpec old_write_time, new_write_time;<br>
+  { // WARNING: Do not assert in this scope.<br>
+    scoped_test_env env;<br>
+    const path file = env.create_file("file", 42);<br>
+    old_write_time = LastWriteTime(file);<br>
+    file_time_type tp(seconds(-5));<br>
+    fs::last_write_time(file, tp, ec);<br>
+    new_write_time = LastWriteTime(file);<br>
+  }<br>
+<br>
+  return !ec && new_write_time.tv_sec < 0;<br>
+}();<br>
+<br>
+static const bool SupportsMaxTime = [] {<br>
+  using namespace std::chrono;<br>
+  TimeSpec max_ts = {};<br>
+  if (!ConvertToTimeSpec(max_ts, file_time_type::max()))<br>
+    return false;<br>
+<br>
+  std::error_code ec;<br>
+  TimeSpec old_write_time, new_write_time;<br>
+  { // WARNING: Do not assert in this scope.<br>
+    scoped_test_env env;<br>
+    const path file = env.create_file("file", 42);<br>
+    old_write_time = LastWriteTime(file);<br>
+    file_time_type tp = file_time_type::max();<br>
+    fs::last_write_time(file, tp, ec);<br>
+    new_write_time = LastWriteTime(file);<br>
+  }<br>
+  return !ec && new_write_time.tv_sec > max_ts.tv_sec - 1;<br>
+}();<br>
+<br>
+static const bool SupportsMinTime = [] {<br>
+  using namespace std::chrono;<br>
+  TimeSpec min_ts = {};<br>
+  if (!ConvertToTimeSpec(min_ts, file_time_type::min()))<br>
+    return false;<br>
+  std::error_code ec;<br>
+  TimeSpec old_write_time, new_write_time;<br>
+  { // WARNING: Do not assert in this scope.<br>
+    scoped_test_env env;<br>
+    const path file = env.create_file("file", 42);<br>
+    old_write_time = LastWriteTime(file);<br>
+    file_time_type tp = file_time_type::min();<br>
+    fs::last_write_time(file, tp, ec);<br>
+    new_write_time = LastWriteTime(file);<br>
+  }<br>
+  return !ec && new_write_time.tv_sec < min_ts.tv_sec + 1;<br>
+}();<br>
+<br>
+static const bool SupportsNanosecondRoundTrip = [] {<br>
+  NanoSec ns(3);<br>
+<br>
+  // Test if the file_time_type period is less than that of nanoseconds.<br>
+  auto ft_dur = duration_cast<file_time_type::<wbr>duration>(ns);<br>
+  if (duration_cast<NanoSec>(ft_<wbr>dur) != ns)<br>
+    return false;<br>
+<br>
+  // Test that the system call we use to set the times also supports nanosecond<br>
+  // resolution. (utimes does not)<br>
+  file_time_type ft(ft_dur);<br>
+  {<br>
+    scoped_test_env env;<br>
+    const path p = env.create_file("file", 42);<br>
+    last_write_time(p, ft);<br>
+    return last_write_time(p) == ft;<br>
+  }<br>
+}();<br>
+<br>
+static const bool SupportsMinRoundTrip = [] {<br>
+  TimeSpec ts = {};<br>
+  if (!ConvertToTimeSpec(ts, file_time_type::min()))<br>
+    return false;<br>
+  file_time_type min_val = {};<br>
+  if (!ConvertFromTimeSpec(min_val, ts))<br>
+    return false;<br>
+  return min_val == file_time_type::min();<br>
+}();<br>
<br>
 } // end namespace<br>
<br>
-// In some configurations, the comparison is tautological and the test is valid.<br>
-// We disable the warning so that we can actually test it regardless. Also, that<br>
-// diagnostic is pretty new, so also don't fail if old clang does not support it<br>
-#if defined(__clang__)<br>
-#pragma clang diagnostic push<br>
-#pragma clang diagnostic ignored "-Wunknown-warning-option"<br>
-#pragma clang diagnostic ignored "-Wunknown-pragmas"<br>
-#pragma clang diagnostic ignored "-Wtautological-constant-<wbr>compare"<br>
-#endif<br>
+static bool CompareTime(TimeSpec t1, TimeSpec t2) {<br>
+  if (SupportsNanosecondRoundTrip)<br>
+    return CompareTimeExact(t1, t2);<br>
+  if (t1.tv_sec != t2.tv_sec)<br>
+    return false;<br>
+<br>
+  auto diff = std::abs(t1.tv_nsec - t2.tv_nsec);<br>
+<br>
+  return diff < duration_cast<NanoSec>(<wbr>MicroSec(1)).count();<br>
+}<br>
+<br>
+static bool CompareTime(file_time_type t1, TimeSpec t2) {<br>
+  TimeSpec ts1 = {};<br>
+  if (!ConvertToTimeSpec(ts1, t1))<br>
+    return false;<br>
+  return CompareTime(ts1, t2);<br>
+}<br>
+<br>
+static bool CompareTime(TimeSpec t1, file_time_type t2) {<br>
+  return CompareTime(t2, t1);<br>
+}<br>
+<br>
+static bool CompareTime(file_time_type t1, file_time_type t2) {<br>
+  auto min_secs = duration_cast<Sec>(file_time_<wbr>type::min().time_since_epoch()<wbr>);<br>
+  bool IsMin =<br>
+      t1.time_since_epoch() < min_secs || t2.time_since_epoch() < min_secs;<br>
+<br>
+  if (SupportsNanosecondRoundTrip && (!IsMin || SupportsMinRoundTrip))<br>
+    return t1 == t2;<br>
+  if (IsMin) {<br>
+    return duration_cast<Sec>(t1.time_<wbr>since_epoch()) ==<br>
+           duration_cast<Sec>(t2.time_<wbr>since_epoch());<br>
+  }<br>
+  file_time_type::duration dur;<br>
+  if (t1 > t2)<br>
+    dur = t1 - t2;<br>
+  else<br>
+    dur = t2 - t1;<br>
+<br>
+  return duration_cast<MicroSec>(dur).<wbr>count() < 1;<br>
+}<br>
<br>
 // Check if a time point is representable on a given filesystem. Check that:<br>
 // (A) 'tp' is representable as a time_t<br>
@@ -162,22 +287,33 @@ static const bool SupportsMinTime = Test<br>
 // (D) 'tp' is not 'file_time_type::min()' or the filesystem supports the min<br>
 //     value.<br>
 inline bool TimeIsRepresentableByFilesyste<wbr>m(file_time_type tp) {<br>
-    using namespace std::chrono;<br>
-    using Lim = std::numeric_limits<std::time_<wbr>t>;<br>
-    auto sec = duration_cast<seconds>(tp.<wbr>time_since_epoch()).count();<br>
-    auto microsec = duration_cast<microseconds>(<wbr>tp.time_since_epoch()).count()<wbr>;<br>
-    if (sec < Lim::min() || sec > Lim::max())   return false;<br>
-    else if (microsec < 0 && !SupportsNegativeTimes) return false;<br>
-    else if (tp == file_time_type::max() && !SupportsMaxTime) return false;<br>
-    else if (tp == file_time_type::min() && !SupportsMinTime) return false;<br>
-    return true;<br>
+  TimeSpec ts = {};<br>
+  if (!ConvertToTimeSpec(ts, tp))<br>
+    return false;<br>
+  else if (tp.time_since_epoch().count() < 0 && !SupportsNegativeTimes)<br>
+    return false;<br>
+  else if (tp == file_time_type::max() && !SupportsMaxTime)<br>
+    return false;<br>
+  else if (tp == file_time_type::min() && !SupportsMinTime)<br>
+    return false;<br>
+  return true;<br>
 }<br>
<br>
 #if defined(__clang__)<br>
 #pragma clang diagnostic pop<br>
 #endif<br>
<br>
-TEST_SUITE(exists_test_suite)<br>
+// Create a sub-second duration using the smallest period the filesystem supports.<br>
+file_time_type::duration SubSec(long long val) {<br>
+  using SubSecT = file_time_type::duration;<br>
+  if (SupportsNanosecondRoundTrip) {<br>
+    return duration_cast<SubSecT>(<wbr>NanoSec(val));<br>
+  } else {<br>
+    return duration_cast<SubSecT>(<wbr>MicroSec(val));<br>
+  }<br>
+}<br>
+<br>
+TEST_SUITE(last_write_time_<wbr>test_suite)<br>
<br>
 TEST_CASE(signature_test)<br>
 {<br>
@@ -202,21 +338,21 @@ TEST_CASE(read_last_write_<wbr>time_static_en<br>
         file_time_type ret = last_write_time(StaticEnv::<wbr>File);<br>
         TEST_CHECK(ret != min);<br>
         TEST_CHECK(ret < C::now());<br>
-        TEST_CHECK(C::to_time_t(ret) == LastWriteTime(StaticEnv::File)<wbr>);<br>
+        TEST_CHECK(CompareTime(ret, LastWriteTime(StaticEnv::File)<wbr>));<br>
<br>
         file_time_type ret2 = last_write_time(StaticEnv::<wbr>SymlinkToFile);<br>
-        TEST_CHECK(ret == ret2);<br>
-        TEST_CHECK(C::to_time_t(ret2) == LastWriteTime(StaticEnv::<wbr>SymlinkToFile));<br>
+        TEST_CHECK(CompareTime(ret, ret2));<br>
+        TEST_CHECK(CompareTime(ret2, LastWriteTime(StaticEnv::<wbr>SymlinkToFile)));<br>
     }<br>
     {<br>
         file_time_type ret = last_write_time(StaticEnv::<wbr>Dir);<br>
         TEST_CHECK(ret != min);<br>
         TEST_CHECK(ret < C::now());<br>
-        TEST_CHECK(C::to_time_t(ret) == LastWriteTime(StaticEnv::Dir))<wbr>;<br>
+        TEST_CHECK(CompareTime(ret, LastWriteTime(StaticEnv::Dir))<wbr>);<br>
<br>
         file_time_type ret2 = last_write_time(StaticEnv::<wbr>SymlinkToDir);<br>
-        TEST_CHECK(ret == ret2);<br>
-        TEST_CHECK(C::to_time_t(ret2) == LastWriteTime(StaticEnv::<wbr>SymlinkToDir));<br>
+        TEST_CHECK(CompareTime(ret, ret2));<br>
+        TEST_CHECK(CompareTime(ret2, LastWriteTime(StaticEnv::<wbr>SymlinkToDir)));<br>
     }<br>
 }<br>
<br>
@@ -230,15 +366,17 @@ TEST_CASE(get_last_write_time_<wbr>dynamic_en<br>
     const path dir = env.create_dir("dir");<br>
<br>
     const auto file_times = GetTimes(file);<br>
-    const std::time_t file_write_time = file_times.write;<br>
+    const TimeSpec file_write_time = file_times.write;<br>
     const auto dir_times = GetTimes(dir);<br>
-    const std::time_t dir_write_time = dir_times.write;<br>
+    const TimeSpec dir_write_time = dir_times.write;<br>
<br>
     file_time_type ftime = last_write_time(file);<br>
-    TEST_CHECK(Clock::to_time_t(<wbr>ftime) == file_write_time);<br>
+    TEST_CHECK(Clock::to_time_t(<wbr>ftime) == file_write_time.tv_sec);<br>
+    TEST_CHECK(CompareTime(ftime, file_write_time));<br>
<br>
     file_time_type dtime = last_write_time(dir);<br>
-    TEST_CHECK(Clock::to_time_t(<wbr>dtime) == dir_write_time);<br>
+    TEST_CHECK(Clock::to_time_t(<wbr>dtime) == dir_write_time.tv_sec);<br>
+    TEST_CHECK(CompareTime(dtime, dir_write_time));<br>
<br>
     SleepFor(Sec(2));<br>
<br>
@@ -253,18 +391,15 @@ TEST_CASE(get_last_write_time_<wbr>dynamic_en<br>
<br>
     TEST_CHECK(ftime2 > ftime);<br>
     TEST_CHECK(dtime2 > dtime);<br>
-    TEST_CHECK(LastWriteTime(file) == Clock::to_time_t(ftime2));<br>
-    TEST_CHECK(LastWriteTime(dir) == Clock::to_time_t(dtime2));<br>
+    TEST_CHECK(CompareTime(<wbr>LastWriteTime(file), ftime2));<br>
+    TEST_CHECK(CompareTime(<wbr>LastWriteTime(dir), dtime2));<br>
 }<br>
<br>
<br>
 TEST_CASE(set_last_write_<wbr>time_dynamic_env_test)<br>
 {<br>
     using Clock = file_time_type::clock;<br>
-    using Sec = std::chrono::seconds;<br>
-    using Hours = std::chrono::hours;<br>
-    using Minutes = std::chrono::minutes;<br>
-    using MicroSec = std::chrono::microseconds;<br>
+    using SubSecT = file_time_type::duration;<br>
     scoped_test_env env;<br>
<br>
     const path file = env.create_file("file", 42);<br>
@@ -272,15 +407,17 @@ TEST_CASE(set_last_write_time_<wbr>dynamic_en<br>
     const auto now = Clock::now();<br>
     const file_time_type epoch_time = now - now.time_since_epoch();<br>
<br>
-    const file_time_type future_time = now + Hours(3) + Sec(42) + MicroSec(17);<br>
-    const file_time_type past_time = now - Minutes(3) - Sec(42) - MicroSec(17);<br>
-    const file_time_type before_epoch_time = epoch_time - Minutes(3) - Sec(42) - MicroSec(17);<br>
+    const file_time_type future_time = now + Hours(3) + Sec(42) + SubSec(17);<br>
+    const file_time_type past_time = now - Minutes(3) - Sec(42) - SubSec(17);<br>
+    const file_time_type before_epoch_time =<br>
+        epoch_time - Minutes(3) - Sec(42) - SubSec(17);<br>
     // FreeBSD has a bug in their utimes implementation where the time is not update<br>
     // when the number of seconds is '-1'.<br>
 #if defined(__FreeBSD__)<br>
-    const file_time_type just_before_epoch_time = epoch_time - Sec(2) - MicroSec(17);<br>
+    const file_time_type just_before_epoch_time =<br>
+        epoch_time - Sec(2) - SubSec(17);<br>
 #else<br>
-    const file_time_type just_before_epoch_time = epoch_time - MicroSec(17);<br>
+    const file_time_type just_before_epoch_time = epoch_time - SubSec(17);<br>
 #endif<br>
<br>
     struct TestCase {<br>
@@ -300,7 +437,8 @@ TEST_CASE(set_last_write_time_<wbr>dynamic_en<br>
     };<br>
     for (const auto& TC : cases) {<br>
         const auto old_times = GetTimes(TC.p);<br>
-        file_time_type old_time(Sec(old_times.write))<wbr>;<br>
+        file_time_type old_time;<br>
+        TEST_REQUIRE(<wbr>ConvertFromTimeSpec(old_time, old_times.write));<br>
<br>
         std::error_code ec = GetTestEC();<br>
         last_write_time(TC.p, TC.new_time, ec);<br>
@@ -310,14 +448,8 @@ TEST_CASE(set_last_write_time_<wbr>dynamic_en<br>
<br>
         if (<wbr>TimeIsRepresentableByFilesyste<wbr>m(TC.new_time)) {<br>
             TEST_CHECK(got_time != old_time);<br>
-            if (TC.new_time < epoch_time) {<br>
-                TEST_CHECK(got_time <= TC.new_time);<br>
-                TEST_CHECK(got_time > TC.new_time - Sec(1));<br>
-            } else {<br>
-                TEST_CHECK(got_time <= TC.new_time + Sec(1));<br>
-                TEST_CHECK(got_time >= TC.new_time - Sec(1));<br>
-            }<br>
-            TEST_CHECK(LastAccessTime(TC.<wbr>p) == old_times.access);<br>
+            TEST_CHECK(CompareTime(got_<wbr>time, TC.new_time));<br>
+            TEST_CHECK(CompareTime(<wbr>LastAccessTime(TC.p), old_times.access));<br>
         }<br>
     }<br>
 }<br>
@@ -325,9 +457,6 @@ TEST_CASE(set_last_write_time_<wbr>dynamic_en<br>
 TEST_CASE(last_write_time_<wbr>symlink_test)<br>
 {<br>
     using Clock = file_time_type::clock;<br>
-    using Sec = std::chrono::seconds;<br>
-    using Hours = std::chrono::hours;<br>
-    using Minutes = std::chrono::minutes;<br>
<br>
     scoped_test_env env;<br>
<br>
@@ -343,77 +472,75 @@ TEST_CASE(last_write_time_<wbr>symlink_test)<br>
     last_write_time(sym, new_time, ec);<br>
     TEST_CHECK(!ec);<br>
<br>
-    const std::time_t new_time_t = Clock::to_time_t(new_time);<br>
     file_time_type  got_time = last_write_time(sym);<br>
-    std::time_t got_time_t = Clock::to_time_t(got_time);<br>
+    TEST_CHECK(!CompareTime(got_<wbr>time, old_times.write));<br>
+    TEST_CHECK(got_time == new_time);<br>
<br>
-    TEST_CHECK(got_time_t != old_times.write);<br>
-    TEST_CHECK(got_time_t == new_time_t);<br>
-    TEST_CHECK(LastWriteTime(file) == new_time_t);<br>
-    TEST_CHECK(LastAccessTime(sym) == old_times.access);<br>
-    TEST_CHECK(GetSymlinkTimes(<wbr>sym) == old_sym_times);<br>
+    TEST_CHECK(CompareTime(<wbr>LastWriteTime(file), new_time));<br>
+    TEST_CHECK(CompareTime(<wbr>LastAccessTime(sym), old_times.access));<br>
+    std::pair<TimeSpec, TimeSpec> sym_times = GetSymlinkTimes(sym);<br>
+    TEST_CHECK(CompareTime(sym_<wbr>times.first, old_sym_times.first));<br>
+    TEST_CHECK(CompareTime(sym_<wbr>times.second, old_sym_times.second));<br>
 }<br>
<br>
<br>
 TEST_CASE(test_write_min_<wbr>time)<br>
 {<br>
     using Clock = file_time_type::clock;<br>
-    using Sec = std::chrono::seconds;<br>
-    using MicroSec = std::chrono::microseconds;<br>
-    using Lim = std::numeric_limits<std::time_<wbr>t>;<br>
     scoped_test_env env;<br>
     const path p = env.create_file("file", 42);<br>
-<br>
-    std::error_code ec = GetTestEC();<br>
+    const file_time_type old_time = last_write_time(p);<br>
     file_time_type new_time = file_time_type::min();<br>
<br>
+    std::error_code ec = GetTestEC();<br>
     last_write_time(p, new_time, ec);<br>
     file_time_type tt = last_write_time(p);<br>
<br>
     if (<wbr>TimeIsRepresentableByFilesyste<wbr>m(new_time)) {<br>
         TEST_CHECK(!ec);<br>
-        TEST_CHECK(tt >= new_time);<br>
-        TEST_CHECK(tt < new_time + Sec(1));<br>
-<br>
-        ec = GetTestEC();<br>
-        last_write_time(p, Clock::now());<br>
+        TEST_CHECK(CompareTime(tt, new_time));<br>
<br>
-        new_time = file_time_type::min() + MicroSec(1);<br>
+        last_write_time(p, old_time);<br>
+        new_time = file_time_type::min() + SubSec(1);<br>
<br>
+        ec = GetTestEC();<br>
         last_write_time(p, new_time, ec);<br>
         tt = last_write_time(p);<br>
<br>
         if (<wbr>TimeIsRepresentableByFilesyste<wbr>m(new_time)) {<br>
             TEST_CHECK(!ec);<br>
-            TEST_CHECK(tt >= new_time);<br>
-            TEST_CHECK(tt < new_time + Sec(1));<br>
+            TEST_CHECK(CompareTime(tt, new_time));<br>
+        } else {<br>
+          TEST_CHECK(ErrorIs(ec, std::errc::value_too_large));<br>
+          TEST_CHECK(tt == old_time);<br>
         }<br>
+    } else {<br>
+      TEST_CHECK(ErrorIs(ec, std::errc::value_too_large));<br>
+      TEST_CHECK(tt == old_time);<br>
     }<br>
 }<br>
<br>
+TEST_CASE(test_write_max_<wbr>time) {<br>
+  using Clock = file_time_type::clock;<br>
+  using Sec = std::chrono::seconds;<br>
+  using Hours = std::chrono::hours;<br>
+<br>
+  scoped_test_env env;<br>
+  const path p = env.create_file("file", 42);<br>
+  const file_time_type old_time = last_write_time(p);<br>
+  file_time_type new_time = file_time_type::max();<br>
+<br>
+  std::error_code ec = GetTestEC();<br>
+  last_write_time(p, new_time, ec);<br>
+  file_time_type tt = last_write_time(p);<br>
<br>
-<br>
-TEST_CASE(test_write_min_max_<wbr>time)<br>
-{<br>
-    using Clock = file_time_type::clock;<br>
-    using Sec = std::chrono::seconds;<br>
-    using Hours = std::chrono::hours;<br>
-    using Lim = std::numeric_limits<std::time_<wbr>t>;<br>
-    scoped_test_env env;<br>
-    const path p = env.create_file("file", 42);<br>
-<br>
-    std::error_code ec = GetTestEC();<br>
-    file_time_type new_time = file_time_type::max();<br>
-<br>
-    ec = GetTestEC();<br>
-    last_write_time(p, new_time, ec);<br>
-    file_time_type tt = last_write_time(p);<br>
-<br>
-    if (<wbr>TimeIsRepresentableByFilesyste<wbr>m(new_time)) {<br>
-        TEST_CHECK(!ec);<br>
-        TEST_CHECK(tt > new_time - Sec(1));<br>
-        TEST_CHECK(tt <= new_time);<br>
-    }<br>
+  if (<wbr>TimeIsRepresentableByFilesyste<wbr>m(new_time)) {<br>
+    TEST_CHECK(!ec);<br>
+    TEST_CHECK(CompareTime(tt, new_time));<br>
+  } else {<br>
+    TEST_CHECK(ErrorIs(ec, std::errc::value_too_large));<br>
+    TEST_CHECK(tt == old_time);<br>
+  }<br>
 }<br>
<br>
 TEST_CASE(test_value_on_<wbr>failure)<br>
@@ -421,8 +548,7 @@ TEST_CASE(test_value_on_<wbr>failure)<br>
     const path p = StaticEnv::DNE;<br>
     std::error_code ec = GetTestEC();<br>
     TEST_CHECK(last_write_time(p, ec) == file_time_type::min());<br>
-    TEST_CHECK(ec);<br>
-    TEST_CHECK(ec != GetTestEC());<br>
+    TEST_CHECK(ErrorIs(ec, std::errc::no_such_file_or_<wbr>directory));<br>
 }<br>
<br>
 TEST_CASE(test_exists_fails)<br>
@@ -434,10 +560,30 @@ TEST_CASE(test_exists_fails)<br>
<br>
     std::error_code ec = GetTestEC();<br>
     TEST_CHECK(last_write_time(<wbr>file, ec) == file_time_type::min());<br>
-    TEST_CHECK(ec);<br>
-    TEST_CHECK(ec != GetTestEC());<br>
+    TEST_CHECK(ErrorIs(ec, std::errc::permission_denied))<wbr>;<br>
<br>
-    TEST_CHECK_THROW(filesystem_<wbr>error, last_write_time(file));<br>
+    ExceptionChecker Checker(file, std::errc::permission_denied,<br>
+                             "last_write_time");<br>
+    TEST_CHECK_THROW_RESULT(<wbr>filesystem_error, Checker, last_write_time(file));<br>
+}<br>
+<br>
+TEST_CASE(my_test) {<br>
+  scoped_test_env env;<br>
+  const path p = env.create_file("file", 42);<br>
+  using namespace std::chrono;<br>
+  using TimeSpec = struct ::timespec;<br>
+  TimeSpec ts[2];<br>
+  ts[0].tv_sec = 0;<br>
+  ts[0].tv_nsec = UTIME_OMIT;<br>
+  ts[1].tv_sec = -1;<br>
+  ts[1].tv_nsec =<br>
+      duration_cast<nanoseconds>(<wbr>seconds(1) - nanoseconds(13)).count();<br>
+  if (::utimensat(AT_FDCWD, p.c_str(), ts, 0) == -1) {<br>
+    TEST_CHECK(false);<br>
+  }<br>
+  TimeSpec new_ts = LastWriteTime(p);<br>
+  TEST_CHECK(ts[1].tv_sec == new_ts.tv_sec);<br>
+  TEST_CHECK(ts[1].tv_nsec == new_ts.tv_nsec);<br>
 }<br>
<br>
 TEST_SUITE_END()<br>
<br>
<br>
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