std::filesystem::file_time_type (3) - Linux Manuals

std::filesystem::file_time_type: std::filesystem::file_time_type

NAME

std::filesystem::file_time_type - std::filesystem::file_time_type

Synopsis

Defined in header <filesystem>
using file_time_type = std::chrono::time_point</*trivial-clock*/>; (since C++17)
                                                                          (until C++20)
using file_time_type = std::chrono::time_point<std::chrono::file_clock>; (since C++20)

Represents file time.

trivial-clock is an implementation-defined type that satisfies TrivialClock and is sufficient to represent the resolution and range of the file time values offered by the filesystem. (until C++20)

Example

// Run this code

  #include <iostream>
  #include <chrono>
  #include <iomanip>
  #include <fstream>
  #include <filesystem>
  namespace fs = std::filesystem;
  using namespace std::chrono_literals;
  int main()
  {
      fs::path p = fs::current_path() / "example.bin";
      std::ofstream(p.c_str()).put('a'); // create file
      auto ftime = fs::last_write_time(p);

      // assuming system_clock for this demo
      // note: not true on MSVC or GCC 9; C++20 will allow portable output
      std::time_t cftime = decltype(ftime)::clock::to_time_t(ftime);
      std::cout << "File write time is " << std::asctime(std::localtime(&cftime)) << '\n';

      fs::last_write_time(p, ftime + 1h); // move file write time 1 hour to the future
      ftime = fs::last_write_time(p); // read back from the filesystem

      cftime = decltype(ftime)::clock::to_time_t(ftime);
      std::cout << "File write time is " << std::asctime(std::localtime(&cftime)) << '\n';
      fs::remove(p);
  }

Possible output:

  File write time is Tue Mar 31 19:47:04 2015

  File write time is Tue Mar 31 20:47:04 2015