std::filesystem::status,std::filesystem::symlink_status(3)

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& (1) (since C++17)
   p );
   std::filesystem::file_status status( const std::filesystem::path&
   p, (2) (since C++17)
                        std::error_code& ec )
   noexcept;
   std::filesystem::file_status symlink_status( const (3) (since C++17)
   std::filesystem::path& p );
   std::filesystem::file_status symlink_status( const
   std::filesystem::path& p, (4) (since C++17)
                        std::error_code& ec )
   noexcept;
   1,2) 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).
   3,4) Same as (1,2) 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
   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
   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 <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
   file_status represents file type and permissions
   (C++17) (class)
   status_known checks whether file status is known
   (C++17) (function)
   is_block_file checks whether the given path refers to block device
   (C++17) (function)
   is_character_file checks whether the given path refers to a character device
   (C++17) (function)
   is_directory checks whether the given path refers to a directory
   (C++17) (function)
   is_fifo checks whether the given path refers to a named pipe
   (C++17) (function)
   is_other checks whether the argument refers to an other file
   (C++17) (function)
   is_regular_file checks whether the argument refers to a regular file
   (C++17) (function)
   is_socket checks whether the argument refers to a named IPC socket
   (C++17) (function)
   is_symlink checks whether the argument refers to a symbolic link
   (C++17) (function)
   exists checks whether path refers to existing file system object
   (C++17) (function)
                     status of the file designated by this directory entry;
   status status of the file/symlink designated by this directory entry
   symlink_status (public member function of std::filesystem::directory_entry)