NAME

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

Synopsis

Defined in header <filesystem>
std::filesystem::file_status status( const std::filesystem::path&
p );

std::filesystem::file_status status( const std::filesystem::path& (1) (since C++17)
p,

std::error_code& ec ) noexcept;
std::filesystem::file_status symlink_status( const
std::filesystem::path& p );

std::filesystem::file_status symlink_status( const (2) (since C++17)
std::filesystem::path& p,

std::error_code& ec ) noexcept;

1) Determines the type and attributes of the filesystem object identified by p as if
by POSIX stat (symlinks are followed to their targets). In the following
description, prms is the result of (m & perms::mask), where m is obtained as if by
taking st_mode from the POSIX struct stat and converting it to the type
std::filesystem::perms.

* If p is a regular file (as if by POSIX S_ISREG), returns
file_status(file_type::regular, prms).
* If p is a directory (as if by POSIX S_ISDIR), returns
file_status(file_type::directory, prms)
* If p is a block special file (as if by POSIX S_ISBLK), returns
file_status(file_type::block, prms)
* If p is a character special file (as if by POSIX S_ISCHR), returns
file_status(file_type::character, prms)
* If p is a fifo or pipe file (as if by POSIX S_ISFIFO), returns
file_status(file_type::fifo, prms)
* If p is a socket (as if by POSIX S_ISSOCK), returns
file_status(file_type::socket, prms)
* If p has an implementation-defined file type, returns
file_status(file_type::A, prms) where A is the implementation-defined
file_type constant for that type.
* If p does not exist, returns file_status(file_type::not_found)
* If p exists but file attributes cannot be determined, e.g. due to lack
of permissions, returns file_status(file_type::unknown)
* If errors prevent even knowing whether p exists, the non-throwing
overload sets ec and returns file_status(file_type::none), and the
throwing overload throws filesystem_error
* Otherwise, returns file_status(file_type::unknown, prms)

2) Same as (1) except that the behavior is as if the POSIX lstat is used (symlinks
are not followed):

* If p is a symlink, returns file_status(file_type::symlink)

Parameters

p - path to examine
ec - out-parameter for error reporting in the non-throwing overload

Return value

The file status (a filesystem::file_status object).

Exceptions

The overload that does not take a std::error_code& parameter throws
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. The overload
taking a std::error_code& parameter sets it to the OS API error code if an OS API
call fails, and executes ec.clear() if no errors occur. Any overload not marked
noexcept may throw std::bad_alloc if memory allocation fails.

Notes

The information provided by this function is usually also provided as a byproduct of
directory iteration, and may be obtained by the member functions of
filesystem::directory_entry. During directory iteration, calling status again is
unnecessary.

Example

// Run this code

#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);
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);
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");
}

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