NAME¶

std::filesystem::directory_entry::status,std::filesystem::directory_entry::symlink_status - std::filesystem::directory_entry::status,std::filesystem::directory_entry::symlink_status

Synopsis¶

std::filesystem::file_status status() const; (1) (since C++17)
std::filesystem::file_status status( std::error_code& ec ) const (2) (since C++17)
noexcept;
std::filesystem::file_status symlink_status() const; (3) (since C++17)
std::filesystem::file_status symlink_status( std::error_code& ec ) (4) (since C++17)
const noexcept;

1,2) Returns status of the entry, as if determined by a filesystem::status call
(symlinks are followed to their targets).
3,4) Returns status of the entry, as if determined by a filesystem::symlink_status
call (symlinks are not followed).

Parameters¶

ec - out-parameter for error reporting in the non-throwing overload

Return value¶

The status of the file referred to by the entry.

Exceptions¶

Any overload not marked noexcept may throw std::bad_alloc if memory allocation
fails.

1,3) Throws std::filesystem::filesystem_error on underlying OS API errors,
constructed with p as the first path argument and the OS error code as the error
code argument.
2,4) Sets a std::error_code& parameter to the OS API error code if an OS API call
fails, and executes ec.clear() if no errors occur.

Notes¶

Many low-level OS APIs for directory traversal retrieve file attributes along with
the next directory entry. The constructors and the non-const member functions of
std::filesystem::directory_iterator store these attributes, if any, in the
pointed-to std::filesystem::directory_entry without calling
directory_entry::refresh, which makes it possible to examine the attributes of the
directory entries as they are being iterated over, without making additional system
calls.

Example¶

// Run this code

#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;
// 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");
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");
}

Possible output:¶

"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

See also¶

refresh updates the cached file attributes
(public member function)
checks whether directory entry refers to existing file system
exists object
(public member function)
is_block_file checks whether the directory entry refers to block device
(public member function)
is_character_file checks whether the directory entry refers to a character device
(public member function)
is_directory checks whether the directory entry refers to a directory
(public member function)
is_fifo checks whether the directory entry refers to a named pipe
(public member function)
is_other checks whether the directory entry refers to an other file
(public member function)
is_regular_file checks whether the directory entry refers to a regular file
(public member function)
is_socket checks whether the directory entry refers to a named IPC socket
(public member function)
is_symlink checks whether the directory entry refers to a symbolic link
(public member function)
file_size returns the size of the file to which the directory entry refers
(public member function)
returns the number of hard links referring to the file to which
hard_link_count the directory entry refers
(public member function)
gets the time of the last data modification of the file to which
last_write_time the directory entry refers
(public member function)