std::experimental::filesystem::directory_entry::status,std::experimental::filesystem::directory_entry::symlink_status (3) - Linux Man Pages

std::experimental::filesystem::directory_entry::status,std::experimental::filesystem::directory_entry::symlink_status: std::experimental::filesystem::directory_entry::status,std::experimental::filesystem::directory_entry::symlink_status

NAME

std::experimental::filesystem::directory_entry::status,std::experimental::filesystem::directory_entry::symlink_status - std::experimental::filesystem::directory_entry::status,std::experimental::filesystem::directory_entry::symlink_status

Synopsis


file_status status() const; (1) (filesystem TS)
file_status status( error_code& ec ) const;
file_status symlink_status() const; (2) (filesystem TS)
file_status symlink_status( error_code& ec ) const;


1) Returns the potentially cached status of the entry, as if determined by a status call (symlinks are followed to their targets)
2) Returns the potentially cached status of the entry, as if determined by a 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


The overload that does not take a error_code& parameter throws filesystem_error on underlying OS API errors, constructed with p as the first argument and the OS error code as the error code argument. std::bad_alloc may be thrown if memory allocation fails. The overload taking a error_code& parameter sets it to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur. This overload has
noexcept specification:
noexcept

Notes


The file status information is usually provided as a byproduct of directory iteration, in which case it is cached and may be obtained by these member functions without the cost of an additional system call. During directory iteration, calling status is unnecessary and accessors such as is_directory should be called with the cached status value, not with a path.

Example


// Run this code


  #include <iostream>
  #include <fstream>
  #include <cstdio>
  #include <cstring>
  #include <experimental/filesystem>
  #include <unistd.h>
  #include <sys/socket.h>
  #include <sys/un.h>
  #include <sys/stat.h>


  namespace fs = std::experimental::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");
      std::ofstream("sandbox/file"); // create regular file
      fs::create_directory("sandbox/dir");
      mkfifo("sandbox/pipe", 0644);
      struct 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, (struct sockaddr*)&addr, sizeof addr);
      fs::create_symlink("file", "sandbox/symlink");


      // 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
      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


                  represents file type and permissions
file_status (class)
                  determines file attributes
status determines file attributes, checking the symlink target
symlink_status (function)
                  checks whether file status is known
status_known (function)
                  checks whether the given path refers to block device
is_block_file (function)
                  checks whether the given path refers to a character device
is_character_file (function)
                  checks whether the given path refers to a directory
is_directory (function)
                  checks whether the given path refers to a named pipe
is_fifo (function)
                  checks whether the argument refers to an other file
is_other (function)
                  checks whether the argument refers to a regular file
is_regular_file (function)
                  checks whether the argument refers to a named IPC socket
is_socket (function)
                  checks whether the argument refers to a symbolic link
is_symlink (function)