std::filesystem::directory_entry::last_write_time

 

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類
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::file_time_type filesystem::perms filesystem::perm_options filesystem::copy_options filesystem::directory_options
函式
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::temp_directory_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
檔案型別
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

 

std::filesystem::directory_entry

成員函式

directory_entry::directory_entry

修改器

directory_entry::operator=

directory_entry::assign

directory_entry::replace_filename

directory_entry::refresh

觀察器

directory_entry::pathdirectory_entry::operator const path&

directory_entry::exists

directory_entry::is_block_file

directory_entry::is_character_file

directory_entry::is_directory

directory_entry::is_fifo

directory_entry::is_other

directory_entry::is_regular_file

directory_entry::is_socket

directory_entry::is_symlink

directory_entry::file_size

directory_entry::hard_link_count

directory_entry::last_write_time

directory_entry::statusdirectory_entry::symlink_status

directory_entry::operator==directory_entry::operator!=directory_entry::operator<directory_entry::operator>directory_entry::operator<=directory_entry::operator>=directory_entry::operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

非成員函式

operator<<

 

std::filesystem::file_time_type last_write_time() const;	(1)	(C++17 起)
std::filesystem::file_time_type last_write_time( std::error_code& ec ) const noexcept;	(2)	(C++17 起)

如果此 directory_entry 中快取了最後修改時間，則返回快取值。否則，返回

1) std::filesystem::last_write_time(path())。

2) std::filesystem::last_write_time(path(), ec)。

引數

ec

-

非丟擲過載中用於錯誤報告的出參

返回值

所引用的檔案系統物件的最後修改時間。

異常

任何未標記為 noexcept 的過載都可能在記憶體分配失敗時丟擲 std::bad_alloc。

1) 在底層 OS API 錯誤時丟擲 std::filesystem::filesystem_error，其構造以 p 作為第一個路徑引數，OS 錯誤碼作為錯誤碼引數。

2) 如果 OS API 呼叫失敗，則將 std::error_code& 引數設定為 OS API 錯誤碼；如果沒有錯誤發生，則執行 ec.clear()。

示例

執行此程式碼

#include <chrono>
#include <ctime>
#include <filesystem>
#include <format>
#include <iostream>
#include <string>
 
std::string to_string(const std::filesystem::file_time_type& ftime)
{
#if __cpp_lib_format
    return std::format("{:%c}", ftime);
#else
    std::time_t cftime = std::chrono::system_clock::to_time_t(
        std::chrono::file_clock::to_sys(ftime));
    std::string str = std::asctime(std::localtime(&cftime));
    str.pop_back(); // rm the trailing '\n' put by `asctime`
    return str;
#endif
}
 
int main()
{
    auto dir = std::filesystem::current_path();
    using Entry = std::filesystem::directory_entry;
    for (Entry const& entry : std::filesystem::directory_iterator(dir))
        std::cout << to_string(entry.last_write_time()) << " : "
                  << entry.path().filename() << '\n';
}

可能的輸出

Wed Sep  6 13:37:13.960314156 2023 : "main.cpp"
Wed Sep  6 13:37:42.690271828 2023 : "a.out"

參閱

last_write_time (C++17)

獲取或設定最後資料修改時間 (函式)