std::filesystem::directory_entry::is_other(3)

NAME
std::filesystem::directory_entry::is_other - std::filesystem::directory_entry::is_other

Synopsis
   bool is_other() const; (1) (since C++17)
   bool is_other( std::error_code& ec ) const noexcept; (2) (since C++17)
   Checks whether the pointed-to object is an other file (not a regular file, directory
   or symlink). Effectively returns:
   1) std::filesystem::is_other(status()).
   2) std::filesystem::is_other(status(ec)).

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

Return value
   true if the referred-to filesystem object is an other file, false otherwise.

Exceptions
   Any overload not marked noexcept may throw std::bad_alloc if memory allocation
   fails.
   1) 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) 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.

Example
// Run this code
 #include <cstdio>
 #include <cstring>
 #include <filesystem>
 #include <fstream>
 #include <functional>
 #include <iostream>
 #include <memory>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/un.h>
 #include <unistd.h>
 namespace fs = std::filesystem;
 void print_entry_type(const std::filesystem::directory_entry& entry)
 {
     std::cout << entry.path() << ": ";
     if (!entry.exists())
         std::cout << "does not exist ";
     if (entry.is_block_file())
         std::cout << "is a block device ";
     if (entry.is_character_file())
         std::cout << "is a character device ";
     if (entry.is_directory())
         std::cout << "is a directory ";
     if (entry.is_fifo())
         std::cout << "is a named IPC pipe ";
     if (entry.is_regular_file())
         std::cout << "is a regular file ";
     if (entry.is_socket())
         std::cout << "is a named IPC socket ";
     if (entry.is_symlink())
         std::cout << "(a symlink)";
     if (entry.is_other())
         std::cout << "(an `other` file)";
     std::cout << '\n';
 }
 template<typename Type, typename Fun>
 class scoped_cleanup
 {
     std::unique_ptr<Type, std::function<void(const Type*)>> u;
 public:
     scoped_cleanup(Type* ptr, Fun fun) : u{ptr, std::move(fun)} {}
 };
 int main()
 {
     // Create files of different kinds.
     std::filesystem::current_path(fs::temp_directory_path());
     const std::filesystem::path sandbox{"sandbox"};
     scoped_cleanup remove_all_at_exit{&sandbox, [](const fs::path* p)
     {
         std::cout << "cleanup: remove_all(" << *p << ")\n";
         fs::remove_all(*p);
     }};
     std::filesystem::create_directory(sandbox);
     std::ofstream{sandbox/"file"}; // Creates a regular file
     std::filesystem::create_directory(sandbox/"dir");
     mkfifo((sandbox/"pipe").string().data(), 0644);
     struct sockaddr_un addr; addr.sun_family = AF_UNIX;
     std::strcpy(addr.sun_path, (sandbox/"sock").string().data());
     int fd{socket(PF_UNIX, SOCK_STREAM, 0)};
     scoped_cleanup close_socket_at_exit{&fd, [](const int* f)
     {
         std::cout << "cleanup: close socket #" << *f << '\n';
         close(*f);
     }};
     bind(fd, reinterpret_cast<sockaddr*>(std::addressof(addr)), sizeof addr);
     fs::create_symlink("file", sandbox/"symlink");
     for (std::filesystem::directory_entry entry: fs::directory_iterator(sandbox))
         print_entry_type(entry);
     // Request file system objects status directly:
     for (const char* str : {"/dev/null", "/dev/cpu", "/usr/include/c++",
                        "/usr/include/asm", "/usr/include/time.h"})
         print_entry_type(fs::directory_entry{str});
 } // Cleanup via scoped_cleanup objects

Possible output:
 "sandbox/symlink": is a regular file (a symlink)
 "sandbox/sock": is a named IPC socket (an `other` file)
 "sandbox/pipe": is a named IPC pipe (an `other` file)
 "sandbox/dir": is a directory
 "sandbox/file": is a regular file
 "/dev/null": is a character device (an `other` file)
 "/dev/cpu": does not exist
 "/usr/include/c++": is a directory
 "/usr/include/asm": is a directory (a symlink)
 "/usr/include/time.h": is a regular file
 cleanup: close socket #3
 cleanup: remove_all("sandbox")

See also
   is_other checks whether the argument refers to an other file
   (C++17) (function)