xref: /aosp_15_r20/external/google-benchmark/src/timers.cc (revision dbb99499c3810fa1611fa2242a2fc446be01a57c)
1*dbb99499SAndroid Build Coastguard Worker // Copyright 2015 Google Inc. All rights reserved.
2*dbb99499SAndroid Build Coastguard Worker //
3*dbb99499SAndroid Build Coastguard Worker // Licensed under the Apache License, Version 2.0 (the "License");
4*dbb99499SAndroid Build Coastguard Worker // you may not use this file except in compliance with the License.
5*dbb99499SAndroid Build Coastguard Worker // You may obtain a copy of the License at
6*dbb99499SAndroid Build Coastguard Worker //
7*dbb99499SAndroid Build Coastguard Worker //     http://www.apache.org/licenses/LICENSE-2.0
8*dbb99499SAndroid Build Coastguard Worker //
9*dbb99499SAndroid Build Coastguard Worker // Unless required by applicable law or agreed to in writing, software
10*dbb99499SAndroid Build Coastguard Worker // distributed under the License is distributed on an "AS IS" BASIS,
11*dbb99499SAndroid Build Coastguard Worker // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12*dbb99499SAndroid Build Coastguard Worker // See the License for the specific language governing permissions and
13*dbb99499SAndroid Build Coastguard Worker // limitations under the License.
14*dbb99499SAndroid Build Coastguard Worker 
15*dbb99499SAndroid Build Coastguard Worker #include "timers.h"
16*dbb99499SAndroid Build Coastguard Worker 
17*dbb99499SAndroid Build Coastguard Worker #include "internal_macros.h"
18*dbb99499SAndroid Build Coastguard Worker 
19*dbb99499SAndroid Build Coastguard Worker #ifdef BENCHMARK_OS_WINDOWS
20*dbb99499SAndroid Build Coastguard Worker #include <shlwapi.h>
21*dbb99499SAndroid Build Coastguard Worker #undef StrCat  // Don't let StrCat in string_util.h be renamed to lstrcatA
22*dbb99499SAndroid Build Coastguard Worker #include <versionhelpers.h>
23*dbb99499SAndroid Build Coastguard Worker #include <windows.h>
24*dbb99499SAndroid Build Coastguard Worker #else
25*dbb99499SAndroid Build Coastguard Worker #include <fcntl.h>
26*dbb99499SAndroid Build Coastguard Worker #if !defined(BENCHMARK_OS_FUCHSIA) && !defined(BENCHMARK_OS_QURT)
27*dbb99499SAndroid Build Coastguard Worker #include <sys/resource.h>
28*dbb99499SAndroid Build Coastguard Worker #endif
29*dbb99499SAndroid Build Coastguard Worker #include <sys/time.h>
30*dbb99499SAndroid Build Coastguard Worker #include <sys/types.h>  // this header must be included before 'sys/sysctl.h' to avoid compilation error on FreeBSD
31*dbb99499SAndroid Build Coastguard Worker #include <unistd.h>
32*dbb99499SAndroid Build Coastguard Worker #if defined BENCHMARK_OS_FREEBSD || defined BENCHMARK_OS_DRAGONFLY || \
33*dbb99499SAndroid Build Coastguard Worker     defined BENCHMARK_OS_MACOSX
34*dbb99499SAndroid Build Coastguard Worker #include <sys/sysctl.h>
35*dbb99499SAndroid Build Coastguard Worker #endif
36*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_MACOSX)
37*dbb99499SAndroid Build Coastguard Worker #include <mach/mach_init.h>
38*dbb99499SAndroid Build Coastguard Worker #include <mach/mach_port.h>
39*dbb99499SAndroid Build Coastguard Worker #include <mach/thread_act.h>
40*dbb99499SAndroid Build Coastguard Worker #endif
41*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_QURT)
42*dbb99499SAndroid Build Coastguard Worker #include <qurt.h>
43*dbb99499SAndroid Build Coastguard Worker #endif
44*dbb99499SAndroid Build Coastguard Worker #endif
45*dbb99499SAndroid Build Coastguard Worker 
46*dbb99499SAndroid Build Coastguard Worker #ifdef BENCHMARK_OS_EMSCRIPTEN
47*dbb99499SAndroid Build Coastguard Worker #include <emscripten.h>
48*dbb99499SAndroid Build Coastguard Worker #endif
49*dbb99499SAndroid Build Coastguard Worker 
50*dbb99499SAndroid Build Coastguard Worker #include <cerrno>
51*dbb99499SAndroid Build Coastguard Worker #include <cstdint>
52*dbb99499SAndroid Build Coastguard Worker #include <cstdio>
53*dbb99499SAndroid Build Coastguard Worker #include <cstdlib>
54*dbb99499SAndroid Build Coastguard Worker #include <cstring>
55*dbb99499SAndroid Build Coastguard Worker #include <ctime>
56*dbb99499SAndroid Build Coastguard Worker #include <iostream>
57*dbb99499SAndroid Build Coastguard Worker #include <limits>
58*dbb99499SAndroid Build Coastguard Worker #include <mutex>
59*dbb99499SAndroid Build Coastguard Worker 
60*dbb99499SAndroid Build Coastguard Worker #include "check.h"
61*dbb99499SAndroid Build Coastguard Worker #include "log.h"
62*dbb99499SAndroid Build Coastguard Worker #include "string_util.h"
63*dbb99499SAndroid Build Coastguard Worker 
64*dbb99499SAndroid Build Coastguard Worker namespace benchmark {
65*dbb99499SAndroid Build Coastguard Worker 
66*dbb99499SAndroid Build Coastguard Worker // Suppress unused warnings on helper functions.
67*dbb99499SAndroid Build Coastguard Worker #if defined(__GNUC__)
68*dbb99499SAndroid Build Coastguard Worker #pragma GCC diagnostic ignored "-Wunused-function"
69*dbb99499SAndroid Build Coastguard Worker #endif
70*dbb99499SAndroid Build Coastguard Worker #if defined(__NVCOMPILER)
71*dbb99499SAndroid Build Coastguard Worker #pragma diag_suppress declared_but_not_referenced
72*dbb99499SAndroid Build Coastguard Worker #endif
73*dbb99499SAndroid Build Coastguard Worker 
74*dbb99499SAndroid Build Coastguard Worker namespace {
75*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_WINDOWS)
MakeTime(FILETIME const & kernel_time,FILETIME const & user_time)76*dbb99499SAndroid Build Coastguard Worker double MakeTime(FILETIME const& kernel_time, FILETIME const& user_time) {
77*dbb99499SAndroid Build Coastguard Worker   ULARGE_INTEGER kernel;
78*dbb99499SAndroid Build Coastguard Worker   ULARGE_INTEGER user;
79*dbb99499SAndroid Build Coastguard Worker   kernel.HighPart = kernel_time.dwHighDateTime;
80*dbb99499SAndroid Build Coastguard Worker   kernel.LowPart = kernel_time.dwLowDateTime;
81*dbb99499SAndroid Build Coastguard Worker   user.HighPart = user_time.dwHighDateTime;
82*dbb99499SAndroid Build Coastguard Worker   user.LowPart = user_time.dwLowDateTime;
83*dbb99499SAndroid Build Coastguard Worker   return (static_cast<double>(kernel.QuadPart) +
84*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(user.QuadPart)) *
85*dbb99499SAndroid Build Coastguard Worker          1e-7;
86*dbb99499SAndroid Build Coastguard Worker }
87*dbb99499SAndroid Build Coastguard Worker #elif !defined(BENCHMARK_OS_FUCHSIA) && !defined(BENCHMARK_OS_QURT)
88*dbb99499SAndroid Build Coastguard Worker double MakeTime(struct rusage const& ru) {
89*dbb99499SAndroid Build Coastguard Worker   return (static_cast<double>(ru.ru_utime.tv_sec) +
90*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(ru.ru_utime.tv_usec) * 1e-6 +
91*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(ru.ru_stime.tv_sec) +
92*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(ru.ru_stime.tv_usec) * 1e-6);
93*dbb99499SAndroid Build Coastguard Worker }
94*dbb99499SAndroid Build Coastguard Worker #endif
95*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_MACOSX)
MakeTime(thread_basic_info_data_t const & info)96*dbb99499SAndroid Build Coastguard Worker double MakeTime(thread_basic_info_data_t const& info) {
97*dbb99499SAndroid Build Coastguard Worker   return (static_cast<double>(info.user_time.seconds) +
98*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(info.user_time.microseconds) * 1e-6 +
99*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(info.system_time.seconds) +
100*dbb99499SAndroid Build Coastguard Worker           static_cast<double>(info.system_time.microseconds) * 1e-6);
101*dbb99499SAndroid Build Coastguard Worker }
102*dbb99499SAndroid Build Coastguard Worker #endif
103*dbb99499SAndroid Build Coastguard Worker #if defined(CLOCK_PROCESS_CPUTIME_ID) || defined(CLOCK_THREAD_CPUTIME_ID)
MakeTime(struct timespec const & ts)104*dbb99499SAndroid Build Coastguard Worker double MakeTime(struct timespec const& ts) {
105*dbb99499SAndroid Build Coastguard Worker   return static_cast<double>(ts.tv_sec) +
106*dbb99499SAndroid Build Coastguard Worker          (static_cast<double>(ts.tv_nsec) * 1e-9);
107*dbb99499SAndroid Build Coastguard Worker }
108*dbb99499SAndroid Build Coastguard Worker #endif
109*dbb99499SAndroid Build Coastguard Worker 
DiagnoseAndExit(const char * msg)110*dbb99499SAndroid Build Coastguard Worker BENCHMARK_NORETURN static void DiagnoseAndExit(const char* msg) {
111*dbb99499SAndroid Build Coastguard Worker   std::cerr << "ERROR: " << msg << std::endl;
112*dbb99499SAndroid Build Coastguard Worker   std::exit(EXIT_FAILURE);
113*dbb99499SAndroid Build Coastguard Worker }
114*dbb99499SAndroid Build Coastguard Worker 
115*dbb99499SAndroid Build Coastguard Worker }  // end namespace
116*dbb99499SAndroid Build Coastguard Worker 
ProcessCPUUsage()117*dbb99499SAndroid Build Coastguard Worker double ProcessCPUUsage() {
118*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_WINDOWS)
119*dbb99499SAndroid Build Coastguard Worker   HANDLE proc = GetCurrentProcess();
120*dbb99499SAndroid Build Coastguard Worker   FILETIME creation_time;
121*dbb99499SAndroid Build Coastguard Worker   FILETIME exit_time;
122*dbb99499SAndroid Build Coastguard Worker   FILETIME kernel_time;
123*dbb99499SAndroid Build Coastguard Worker   FILETIME user_time;
124*dbb99499SAndroid Build Coastguard Worker   if (GetProcessTimes(proc, &creation_time, &exit_time, &kernel_time,
125*dbb99499SAndroid Build Coastguard Worker                       &user_time))
126*dbb99499SAndroid Build Coastguard Worker     return MakeTime(kernel_time, user_time);
127*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("GetProccessTimes() failed");
128*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_QURT)
129*dbb99499SAndroid Build Coastguard Worker   // Note that qurt_timer_get_ticks() is no longer documented as of SDK 5.3.0,
130*dbb99499SAndroid Build Coastguard Worker   // and doesn't appear to work on at least some devices (eg Samsung S22),
131*dbb99499SAndroid Build Coastguard Worker   // so let's use the actually-documented and apparently-equivalent
132*dbb99499SAndroid Build Coastguard Worker   // qurt_sysclock_get_hw_ticks() call instead.
133*dbb99499SAndroid Build Coastguard Worker   return static_cast<double>(
134*dbb99499SAndroid Build Coastguard Worker              qurt_timer_timetick_to_us(qurt_sysclock_get_hw_ticks())) *
135*dbb99499SAndroid Build Coastguard Worker          1.0e-6;
136*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_EMSCRIPTEN)
137*dbb99499SAndroid Build Coastguard Worker   // clock_gettime(CLOCK_PROCESS_CPUTIME_ID, ...) returns 0 on Emscripten.
138*dbb99499SAndroid Build Coastguard Worker   // Use Emscripten-specific API. Reported CPU time would be exactly the
139*dbb99499SAndroid Build Coastguard Worker   // same as total time, but this is ok because there aren't long-latency
140*dbb99499SAndroid Build Coastguard Worker   // synchronous system calls in Emscripten.
141*dbb99499SAndroid Build Coastguard Worker   return emscripten_get_now() * 1e-3;
142*dbb99499SAndroid Build Coastguard Worker #elif defined(CLOCK_PROCESS_CPUTIME_ID) && !defined(BENCHMARK_OS_MACOSX)
143*dbb99499SAndroid Build Coastguard Worker   // FIXME We want to use clock_gettime, but its not available in MacOS 10.11.
144*dbb99499SAndroid Build Coastguard Worker   // See https://github.com/google/benchmark/pull/292
145*dbb99499SAndroid Build Coastguard Worker   struct timespec spec;
146*dbb99499SAndroid Build Coastguard Worker   if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &spec) == 0)
147*dbb99499SAndroid Build Coastguard Worker     return MakeTime(spec);
148*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("clock_gettime(CLOCK_PROCESS_CPUTIME_ID, ...) failed");
149*dbb99499SAndroid Build Coastguard Worker #else
150*dbb99499SAndroid Build Coastguard Worker   struct rusage ru;
151*dbb99499SAndroid Build Coastguard Worker   if (getrusage(RUSAGE_SELF, &ru) == 0) return MakeTime(ru);
152*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("getrusage(RUSAGE_SELF, ...) failed");
153*dbb99499SAndroid Build Coastguard Worker #endif
154*dbb99499SAndroid Build Coastguard Worker }
155*dbb99499SAndroid Build Coastguard Worker 
ThreadCPUUsage()156*dbb99499SAndroid Build Coastguard Worker double ThreadCPUUsage() {
157*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_WINDOWS)
158*dbb99499SAndroid Build Coastguard Worker   HANDLE this_thread = GetCurrentThread();
159*dbb99499SAndroid Build Coastguard Worker   FILETIME creation_time;
160*dbb99499SAndroid Build Coastguard Worker   FILETIME exit_time;
161*dbb99499SAndroid Build Coastguard Worker   FILETIME kernel_time;
162*dbb99499SAndroid Build Coastguard Worker   FILETIME user_time;
163*dbb99499SAndroid Build Coastguard Worker   GetThreadTimes(this_thread, &creation_time, &exit_time, &kernel_time,
164*dbb99499SAndroid Build Coastguard Worker                  &user_time);
165*dbb99499SAndroid Build Coastguard Worker   return MakeTime(kernel_time, user_time);
166*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_QURT)
167*dbb99499SAndroid Build Coastguard Worker   // Note that qurt_timer_get_ticks() is no longer documented as of SDK 5.3.0,
168*dbb99499SAndroid Build Coastguard Worker   // and doesn't appear to work on at least some devices (eg Samsung S22),
169*dbb99499SAndroid Build Coastguard Worker   // so let's use the actually-documented and apparently-equivalent
170*dbb99499SAndroid Build Coastguard Worker   // qurt_sysclock_get_hw_ticks() call instead.
171*dbb99499SAndroid Build Coastguard Worker   return static_cast<double>(
172*dbb99499SAndroid Build Coastguard Worker              qurt_timer_timetick_to_us(qurt_sysclock_get_hw_ticks())) *
173*dbb99499SAndroid Build Coastguard Worker          1.0e-6;
174*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_MACOSX)
175*dbb99499SAndroid Build Coastguard Worker   // FIXME We want to use clock_gettime, but its not available in MacOS 10.11.
176*dbb99499SAndroid Build Coastguard Worker   // See https://github.com/google/benchmark/pull/292
177*dbb99499SAndroid Build Coastguard Worker   mach_msg_type_number_t count = THREAD_BASIC_INFO_COUNT;
178*dbb99499SAndroid Build Coastguard Worker   thread_basic_info_data_t info;
179*dbb99499SAndroid Build Coastguard Worker   mach_port_t thread = pthread_mach_thread_np(pthread_self());
180*dbb99499SAndroid Build Coastguard Worker   if (thread_info(thread, THREAD_BASIC_INFO,
181*dbb99499SAndroid Build Coastguard Worker                   reinterpret_cast<thread_info_t>(&info),
182*dbb99499SAndroid Build Coastguard Worker                   &count) == KERN_SUCCESS) {
183*dbb99499SAndroid Build Coastguard Worker     return MakeTime(info);
184*dbb99499SAndroid Build Coastguard Worker   }
185*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("ThreadCPUUsage() failed when evaluating thread_info");
186*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_EMSCRIPTEN)
187*dbb99499SAndroid Build Coastguard Worker   // Emscripten doesn't support traditional threads
188*dbb99499SAndroid Build Coastguard Worker   return ProcessCPUUsage();
189*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_RTEMS)
190*dbb99499SAndroid Build Coastguard Worker   // RTEMS doesn't support CLOCK_THREAD_CPUTIME_ID. See
191*dbb99499SAndroid Build Coastguard Worker   // https://github.com/RTEMS/rtems/blob/master/cpukit/posix/src/clockgettime.c
192*dbb99499SAndroid Build Coastguard Worker   return ProcessCPUUsage();
193*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_ZOS)
194*dbb99499SAndroid Build Coastguard Worker   // z/OS doesn't support CLOCK_THREAD_CPUTIME_ID.
195*dbb99499SAndroid Build Coastguard Worker   return ProcessCPUUsage();
196*dbb99499SAndroid Build Coastguard Worker #elif defined(BENCHMARK_OS_SOLARIS)
197*dbb99499SAndroid Build Coastguard Worker   struct rusage ru;
198*dbb99499SAndroid Build Coastguard Worker   if (getrusage(RUSAGE_LWP, &ru) == 0) return MakeTime(ru);
199*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("getrusage(RUSAGE_LWP, ...) failed");
200*dbb99499SAndroid Build Coastguard Worker #elif defined(CLOCK_THREAD_CPUTIME_ID)
201*dbb99499SAndroid Build Coastguard Worker   struct timespec ts;
202*dbb99499SAndroid Build Coastguard Worker   if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) == 0) return MakeTime(ts);
203*dbb99499SAndroid Build Coastguard Worker   DiagnoseAndExit("clock_gettime(CLOCK_THREAD_CPUTIME_ID, ...) failed");
204*dbb99499SAndroid Build Coastguard Worker #else
205*dbb99499SAndroid Build Coastguard Worker #error Per-thread timing is not available on your system.
206*dbb99499SAndroid Build Coastguard Worker #endif
207*dbb99499SAndroid Build Coastguard Worker }
208*dbb99499SAndroid Build Coastguard Worker 
LocalDateTimeString()209*dbb99499SAndroid Build Coastguard Worker std::string LocalDateTimeString() {
210*dbb99499SAndroid Build Coastguard Worker   // Write the local time in RFC3339 format yyyy-mm-ddTHH:MM:SS+/-HH:MM.
211*dbb99499SAndroid Build Coastguard Worker   typedef std::chrono::system_clock Clock;
212*dbb99499SAndroid Build Coastguard Worker   std::time_t now = Clock::to_time_t(Clock::now());
213*dbb99499SAndroid Build Coastguard Worker   const std::size_t kTzOffsetLen = 6;
214*dbb99499SAndroid Build Coastguard Worker   const std::size_t kTimestampLen = 19;
215*dbb99499SAndroid Build Coastguard Worker 
216*dbb99499SAndroid Build Coastguard Worker   std::size_t tz_len;
217*dbb99499SAndroid Build Coastguard Worker   std::size_t timestamp_len;
218*dbb99499SAndroid Build Coastguard Worker   long int offset_minutes;
219*dbb99499SAndroid Build Coastguard Worker   char tz_offset_sign = '+';
220*dbb99499SAndroid Build Coastguard Worker   // tz_offset is set in one of three ways:
221*dbb99499SAndroid Build Coastguard Worker   // * strftime with %z - This either returns empty or the ISO 8601 time.  The
222*dbb99499SAndroid Build Coastguard Worker   // maximum length an
223*dbb99499SAndroid Build Coastguard Worker   //   ISO 8601 string can be is 7 (e.g. -03:30, plus trailing zero).
224*dbb99499SAndroid Build Coastguard Worker   // * snprintf with %c%02li:%02li - The maximum length is 41 (one for %c, up to
225*dbb99499SAndroid Build Coastguard Worker   // 19 for %02li,
226*dbb99499SAndroid Build Coastguard Worker   //   one for :, up to 19 %02li, plus trailing zero).
227*dbb99499SAndroid Build Coastguard Worker   // * A fixed string of "-00:00".  The maximum length is 7 (-00:00, plus
228*dbb99499SAndroid Build Coastguard Worker   // trailing zero).
229*dbb99499SAndroid Build Coastguard Worker   //
230*dbb99499SAndroid Build Coastguard Worker   // Thus, the maximum size this needs to be is 41.
231*dbb99499SAndroid Build Coastguard Worker   char tz_offset[41];
232*dbb99499SAndroid Build Coastguard Worker   // Long enough buffer to avoid format-overflow warnings
233*dbb99499SAndroid Build Coastguard Worker   char storage[128];
234*dbb99499SAndroid Build Coastguard Worker 
235*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_WINDOWS)
236*dbb99499SAndroid Build Coastguard Worker   std::tm* timeinfo_p = ::localtime(&now);
237*dbb99499SAndroid Build Coastguard Worker #else
238*dbb99499SAndroid Build Coastguard Worker   std::tm timeinfo;
239*dbb99499SAndroid Build Coastguard Worker   std::tm* timeinfo_p = &timeinfo;
240*dbb99499SAndroid Build Coastguard Worker   ::localtime_r(&now, &timeinfo);
241*dbb99499SAndroid Build Coastguard Worker #endif
242*dbb99499SAndroid Build Coastguard Worker 
243*dbb99499SAndroid Build Coastguard Worker   tz_len = std::strftime(tz_offset, sizeof(tz_offset), "%z", timeinfo_p);
244*dbb99499SAndroid Build Coastguard Worker 
245*dbb99499SAndroid Build Coastguard Worker   if (tz_len < kTzOffsetLen && tz_len > 1) {
246*dbb99499SAndroid Build Coastguard Worker     // Timezone offset was written. strftime writes offset as +HHMM or -HHMM,
247*dbb99499SAndroid Build Coastguard Worker     // RFC3339 specifies an offset as +HH:MM or -HH:MM. To convert, we parse
248*dbb99499SAndroid Build Coastguard Worker     // the offset as an integer, then reprint it to a string.
249*dbb99499SAndroid Build Coastguard Worker 
250*dbb99499SAndroid Build Coastguard Worker     offset_minutes = ::strtol(tz_offset, NULL, 10);
251*dbb99499SAndroid Build Coastguard Worker     if (offset_minutes < 0) {
252*dbb99499SAndroid Build Coastguard Worker       offset_minutes *= -1;
253*dbb99499SAndroid Build Coastguard Worker       tz_offset_sign = '-';
254*dbb99499SAndroid Build Coastguard Worker     }
255*dbb99499SAndroid Build Coastguard Worker 
256*dbb99499SAndroid Build Coastguard Worker     tz_len = static_cast<size_t>(
257*dbb99499SAndroid Build Coastguard Worker         ::snprintf(tz_offset, sizeof(tz_offset), "%c%02li:%02li",
258*dbb99499SAndroid Build Coastguard Worker                    tz_offset_sign, offset_minutes / 100, offset_minutes % 100));
259*dbb99499SAndroid Build Coastguard Worker     BM_CHECK(tz_len == kTzOffsetLen);
260*dbb99499SAndroid Build Coastguard Worker     ((void)tz_len);  // Prevent unused variable warning in optimized build.
261*dbb99499SAndroid Build Coastguard Worker   } else {
262*dbb99499SAndroid Build Coastguard Worker     // Unknown offset. RFC3339 specifies that unknown local offsets should be
263*dbb99499SAndroid Build Coastguard Worker     // written as UTC time with -00:00 timezone.
264*dbb99499SAndroid Build Coastguard Worker #if defined(BENCHMARK_OS_WINDOWS)
265*dbb99499SAndroid Build Coastguard Worker     // Potential race condition if another thread calls localtime or gmtime.
266*dbb99499SAndroid Build Coastguard Worker     timeinfo_p = ::gmtime(&now);
267*dbb99499SAndroid Build Coastguard Worker #else
268*dbb99499SAndroid Build Coastguard Worker     ::gmtime_r(&now, &timeinfo);
269*dbb99499SAndroid Build Coastguard Worker #endif
270*dbb99499SAndroid Build Coastguard Worker 
271*dbb99499SAndroid Build Coastguard Worker     strncpy(tz_offset, "-00:00", kTzOffsetLen + 1);
272*dbb99499SAndroid Build Coastguard Worker   }
273*dbb99499SAndroid Build Coastguard Worker 
274*dbb99499SAndroid Build Coastguard Worker   timestamp_len =
275*dbb99499SAndroid Build Coastguard Worker       std::strftime(storage, sizeof(storage), "%Y-%m-%dT%H:%M:%S", timeinfo_p);
276*dbb99499SAndroid Build Coastguard Worker   BM_CHECK(timestamp_len == kTimestampLen);
277*dbb99499SAndroid Build Coastguard Worker   // Prevent unused variable warning in optimized build.
278*dbb99499SAndroid Build Coastguard Worker   ((void)kTimestampLen);
279*dbb99499SAndroid Build Coastguard Worker 
280*dbb99499SAndroid Build Coastguard Worker   std::strncat(storage, tz_offset, sizeof(storage) - timestamp_len - 1);
281*dbb99499SAndroid Build Coastguard Worker   return std::string(storage);
282*dbb99499SAndroid Build Coastguard Worker }
283*dbb99499SAndroid Build Coastguard Worker 
284*dbb99499SAndroid Build Coastguard Worker }  // end namespace benchmark
285