std::filesystem::directory_entry::is_fifo

#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

"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")