std::filesystem::file_type

 

C++

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执行支持库 (C++26)

技术规范

符号索引

外部库

 

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

 

定义在头文件 <filesystem> 中
enum class file_type {     none = /* 未指定 */,     not_found = /* 未指定 */,     regular = /* 未指定 */,     directory = /* 未指定 */,     symlink = /* 未指定 */,     block = /* 未指定 */,     character = /* 未指定 */,     fifo = /* 未指定 */,     socket = /* 未指定 */,     unknown = /* 未指定 */,     /* 实现定义 */ };		(自 C++17 起)

file_type 定义常量，指示路径所指向的文件或目录的类型。枚举器的值是不同的。

常量

常量	含义
none	表示文件状态尚未评估，或者在评估时发生了错误
not_found	表示未找到文件（这不算错误）
regular	普通文件
directory	目录
symlink	符号链接
block	块特殊文件
character	字符特殊文件
fifo	FIFO（也称为管道）文件
socket	套接字文件
实现定义	为实现支持的每种附加文件类型定义一个附加的实现定义常量（例如，MSVC STL 为 NTFS 联接 定义 junction）
unknown	文件存在，但无法确定其类型

示例

运行此代码

#include <cstdio>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <unistd.h>
 
namespace fs = std::filesystem;
 
void demo_status(const fs::path& p, fs::file_status s)
{
    std::cout << p;
    switch (s.type())
    {
        case fs::file_type::none:
            std::cout << " has `not-evaluated-yet` type";
            break;
        case fs::file_type::not_found:
            std::cout << " does not exist";
            break;
        case fs::file_type::regular:
            std::cout << " is a regular file";
            break;
        case fs::file_type::directory:
            std::cout << " is a directory";
            break;
        case fs::file_type::symlink:
            std::cout << " is a symlink";
            break;
        case fs::file_type::block:
            std::cout << " is a block device";
            break;
        case fs::file_type::character:
            std::cout << " is a character device";
            break;
        case fs::file_type::fifo:
            std::cout << " is a named IPC pipe";
            break;
        case fs::file_type::socket:
            std::cout << " is a named IPC socket";
            break;
        case fs::file_type::unknown:
            std::cout << " has `unknown` type";
            break;
        default:
            std::cout << " has `implementation-defined` type";
            break;
    }
    std::cout << '\n';
}
 
int main()
{
    // create files of different kinds
    fs::create_directory("sandbox");
    fs::create_directory("sandbox/dir");
    std::ofstream{"sandbox/file"}; // create regular file
    fs::create_symlink("file", "sandbox/symlink");
 
    mkfifo("sandbox/pipe", 0644);
    sockaddr_un addr;
    addr.sun_family = AF_UNIX;
    std::strcpy(addr.sun_path, "sandbox/sock");
    int fd = socket(PF_UNIX, SOCK_STREAM, 0);
    bind(fd, reinterpret_cast<sockaddr*>(&addr), sizeof addr);
 
    // demo different status accessors
    for (auto it{fs::directory_iterator("sandbox")}; it != fs::directory_iterator(); ++it)
        demo_status(*it, it->symlink_status()); // use cached status from directory entry
    demo_status("/dev/null", fs::status("/dev/null")); // direct calls to status
    demo_status("/dev/sda", fs::status("/dev/sda"));
    demo_status("sandbox/no", fs::status("/sandbox/no"));
 
    // cleanup (prefer std::unique_ptr-based custom deleters)
    close(fd);
    fs::remove_all("sandbox");
}

可能输出

"sandbox/file" is a regular file
"sandbox/dir" is a directory
"sandbox/pipe" is a named IPC pipe
"sandbox/sock" is a named IPC socket
"sandbox/symlink" is a symlink
"/dev/null" is a character device
"/dev/sda" is a block device
"sandbox/no" does not exist

另请参阅

file_status (C++17)	表示文件类型和权限 (类)
is_block_file (C++17)	检查给定路径是否引用块设备 (函数)
is_character_file (C++17)	检查给定路径是否引用字符设备 (函数)
is_directory (C++17)	检查给定路径是否引用目录 (函数)
is_fifo (C++17)	检查给定路径是否引用命名管道 (函数)
is_other (C++17)	检查参数是否引用其他文件 (函数)
is_socket (C++17)	检查参数是否引用命名 IPC 套接字 (函数)
is_symlink (C++17)	检查参数是否引用符号链接 (函数)
is_regular_file	检查目录项是否引用普通文件 (std::filesystem::directory_entry 的公共成员函数)