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#include <iostream>
#include <filesystem>
#include <chrono>
using namespace std;
using namespace filesystem;
using namespace chrono;
// t1;
// 1'573'443'680 '202'029'390
// -4'864'220'319 '797'970'245
//
// t0:
// 1'573'443'602 '813'273'869
// -4'864'220'397 '186'725'741
// 6'437'663'999
//demo
int main()
{
// get `now' according to the system_clock and
// the __file_clock, compute their difference in
// nanoseconds and seconds:
auto systemNow = system_clock::now().time_since_epoch();
auto fileNow = __file_clock::now().time_since_epoch();
duration diffNano = systemNow - fileNow;
time_t diff = diffNano.count() / 1'000'000'000;
cout << "system_clock now: " << systemNow.count() << "\n"
"__file_clock now: " << fileNow.count() << "\n"
"difference (nano): " << diffNano.count() << "\n"
"difference (secs): " << diff << '\n';
auto lwt = last_write_time("lastwritetime.cc").time_since_epoch();
time_t seconds = diff + system_clock::to_time_t(
time_point<system_clock>{ nanoseconds(lwt) } );
cout << "lastwritetime.cc's time: " <<
put_time(gmtime(&seconds), "%c") << '\n';
seconds =
system_clock::to_time_t(time_point<system_clock>{ diffNano });
cout << "__file_clock's epoch time expressed using the system_clock:\n"
" " << put_time(gmtime(&seconds), "%c") << "\n"
"same, merely using the difference in `now' clock-seconds:\n"
" " << put_time(gmtime(&diff), "%c") << '\n';
}
//=
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