Movatterモバイル変換

[0]ホーム
URL:

cppreference.com
Namespaces
Variants
    Actions

      std::experimental::filesystem::last_write_time

      From cppreference.com
      <cpp‎ |experimental‎ |fs
       
       
       
      Filesystem library
      Classes
      Functions
      File types
       
      Defined in header<experimental/filesystem>
      file_time_type last_write_time(const path& p);
      file_time_type last_write_time(const path& p, error_code& ec)
      		 (1)(filesystem TS)
      void last_write_time(const path& p, file_time_type new_time);
      void last_write_time(const path& p, file_time_type new_time, error_code& ec);
      		 (2)(filesystem TS)
      1) Returns the time of the last modification ofp, determined as if by accessing the memberst_mtime of the POSIXstat (symlinks are followed).The non-throwing overload returnsfile_time_type::min() on errors.
      2) Changes the time of the last modification ofp, as if by POSIXfutimens (symlinks are followed).

      Contents

      [edit]Parameters

      p - path to examine or modify
      new_time - new modification time
      ec - out-parameter for error reporting in the non-throwing overload

      [edit]Return value

      1) The time of the last modification ofp.
      2) (none)

      [edit]Exceptions

      The overload that does not take anerror_code& parameter throwsfilesystem_error on underlying OS API errors, constructed withp as the first argument and the OS error code as the error code argument.std::bad_alloc may be thrown if memory allocation fails. The overload taking anerror_code& parameter sets it to the OS API error code if an OS API call fails, and executesec.clear() if no errors occur. This overload has
      noexcept specification:  
      noexcept
        

      [edit]Notes

      It is not guaranteed that immediately after setting the write time, the value returned by(1) is the same as what was passed as the argument to(2) because the file system's time may be more granular thanfile_time_type.

      [edit]Example

      Run this code
      #include <chrono>#include <experimental/filesystem>#include <fstream>#include <iomanip>#include <iostream>namespace fs= std::experimental::filesystem;usingnamespace std::chrono_literals; int main(){    fs::path p= fs::current_path()/"example.bin";std::ofstream(p.c_str()).put('a');// create fileauto ftime= fs::last_write_time(p); std::time_t cftime= decltype(ftime)::clock::to_time_t(ftime);// assuming system_clockstd::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

      [edit]See also

      represents file time values
      (typedef)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/experimental/fs/last_write_time&oldid=158854"
      [8]ページ先頭
      ©2009-2026 Movatter.jp