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std::filesystem::file_time_type

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

#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

See also

(C++17)
gets or sets the time of the last data modification
(function)

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