std::filesystem::directory_entry::symlink_status
std::filesystem::file_status status() const; std::filesystem::file_status status( std::error_code& ec ) const; | (1) | (since C++17) |
|---|---|---|
std::filesystem::file_status symlink_status() const; std::filesystem::file_status symlink_status( std::error_code& ec ) const; | (2) | (since C++17) |
1%29返回条目的状态，仿佛由地位调用%28符号链接被跟踪到其目标%29
2%29返回条目的状态，仿佛由符号链接[医]地位调用%28符号链接不跟随%29
参数
ec | - | out-parameter for error reporting in the non-throwing overload |
|---|
返回值
条目所引用的文件的状态。
例外
不占用std::error_code&参数抛文件系统[医]误差关于基础OS API错误，使用p作为第一个参数和操作系统错误代码作为错误代码参数。std::bad_alloc如果内存分配失败，则可能引发。过载std::error_code&参数，如果OSAPI调用失败，则将其设置为OSAPI错误代码，并执行ec.clear()如果没有错误发生。这个过载
noexcept规格：
noexcept
注记
文件状态信息通常作为目录迭代的副产品提供。都是助推。文件系统和技术规范版本的文件系统库缓存状态，这些成员函数访问缓存的值而不需要额外的系统调用，简化了访问器的使用，例如is_directory在目录迭代期间。状态缓存在合并到C++17期间通过lwg 2653...
例
二次
#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstring>
#include <filesystem>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
namespace fs = std::filesystem;
void demo_status(const fs::path& p, fs::file_status s)
{
std::cout << p;
// alternative: switch(s.type()) { case fs::file_type::regular: ...}
if(fs::is_regular_file(s)) std::cout << " is a regular file\n";
if(fs::is_directory(s)) std::cout << " is a directory\n";
if(fs::is_block_file(s)) std::cout << " is a block device\n";
if(fs::is_character_file(s)) std::cout << " is a character device\n";
if(fs::is_fifo(s)) std::cout << " is a named IPC pipe\n";
if(fs::is_socket(s)) std::cout << " is a named IPC socket\n";
if(fs::is_symlink(s)) std::cout << " is a symlink\n";
if(!fs::exists(s)) std::cout << " does not exist\n";
}
int main()
{
// create files of different kinds
fs::create_directory("sandbox");
std::ofstream("sandbox/file"); // create regular file
fs::create_directory("sandbox/dir");
mkfifo("sandbox/pipe", 0644);
struct 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, (struct sockaddr*)&addr, sizeof addr);
fs::create_symlink("file", "sandbox/symlink");
// 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
close(fd);
fs::remove_all("sandbox");
}二次
可能的产出：
二次
"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二次
另见
file_status (C++17) | represents file type and permissions (class) |
|---|---|
statussymlink_status (C++17)(C++17) | determines file attributesdetermines file attributes, checking the symlink target (function) |
status_known (C++17) | checks whether file status is known (function) |
is_block_file (C++17) | checks whether the given path refers to block device (function) |
is_character_file (C++17) | checks whether the given path refers to a character device (function) |
is_directory (C++17) | checks whether the given path refers to a directory (function) |
is_fifo (C++17) | checks whether the given path refers to a named pipe (function) |
is_other (C++17) | checks whether the argument refers to an other file (function) |
is_regular_file (C++17) | checks whether the argument refers to a regular file (function) |
is_socket (C++17) | checks whether the argument refers to a named IPC socket (function) |
is_symlink (C++17) | checks whether the argument refers to a symbolic link (function) |
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