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

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)