std::filesystem::file_time_type

 

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技术规范

 

文件系统库

类
filesystem::path filesystem::filesystem_error filesystem::directory_entry filesystem::directory_iterator filesystem::recursive_directory_iterator filesystem::file_status	filesystem::space_info filesystem::file_type filesystem::perms filesystem::perm_options filesystem::copy_options filesystem::directory_options filesystem::file_time_type
函数
filesystem::absolute filesystem::canonicalfilesystem::weakly_canonical filesystem::relativefilesystem::proximate filesystem::copy filesystem::copy_file filesystem::copy_symlink filesystem::create_directory filesystem::create_directories filesystem::create_hard_link filesystem::create_symlink filesystem::create_directory_symlink filesystem::current_path	filesystem::exists filesystem::equivalent filesystem::file_size filesystem::hard_link_count filesystem::last_write_time filesystem::permissions filesystem::read_symlink filesystem::remove filesystem::remove_all filesystem::rename filesystem::resize_file filesystem::space filesystem::status filesystem::symlink_status filesystem::temp_directory_path
文件类型
filesystem::is_block_file filesystem::is_character_file filesystem::is_directory filesystem::is_empty filesystem::status_known	filesystem::is_fifo filesystem::is_other filesystem::is_regular_file filesystem::is_socket filesystem::is_symlink

 

定义于头文件 <filesystem>
using file_time_type = std::chrono::time_point</*trivial-clock*/>;		(C++17 起) (C++20 前)
using file_time_type = std::chrono::time_point<std::chrono::file_clock>;		(C++20 起)

表示文件时间。

trivial-clock 是一个满足平凡时钟 (TrivialClock) ，并足以表示文件系统提供的文件时间值与精度的实现定义类型。

(C++20 前)

示例

运行此代码

#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'); // 创建文件
    auto ftime = fs::last_write_time(p);
 
    std::time_t cftime = decltype(ftime)::clock::to_time_t(ftime);
 
    // 对此演示假定为 system_clock
    // 注意： MSVC 上非真； C++20 将允许可移植的输出
    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); // 向未来移动文件写入时间 1 小时
    ftime = fs::last_write_time(p); // 从文件系统回读
 
    cftime = decltype(ftime)::clock::to_time_t(ftime);
    std::cout << "File write time is " << std::asctime(std::localtime(&cftime)) << '\n';
    fs::remove(p);
}

可能的输出：

File write time is Tue Mar 31 19:47:04 2015
 
File write time is Tue Mar 31 20:47:04 2015

参阅

last_write_time (C++17)

获取或设置最近一次数据修改的时间 (函数)