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std::filesy...aracter_file(3)  C++ Standard Libary std::filesy...aracter_file(3)

NAME
     std::filesystem::directory_entry::is_character_file  - std::filesystem::di-
     rectory_entry::is_character_file

Synopsis
	bool is_character_file() const; 			      (1) (since
     C++17)
	bool is_character_file( std::error_code& ec ) const noexcept; (2) (since
     C++17)

	Checks whether the pointed-to object is a character device.  Effectively
     returns:

	1) std::filesystem::is_character_file(status()),
	2) std::filesystem::is_character_file(status(ec)).

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

Return value
	true  if  the referred-to filesystem object is a character device, false
     otherwise.

Exceptions
	Any overload not marked noexcept may throw std::bad_alloc if memory  al-
     location
	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_itera-
     tor(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_character_file  checks  whether  the given path refers to a character
     device
	(C++17) 	  (function)

http://cppreference.com 	   2024.06.10	   std::filesy...aracter_file(3)
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