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      std::experimental::filesystem::is_socket

      From cppreference.com
      <cpp‎ |experimental‎ |fs
       
       
       
      Filesystem library
      Classes
      Functions
      File types
       
      Defined in header<experimental/filesystem>
      bool is_socket( file_status s);
      (1)(filesystem TS)
      bool is_socket(const path& p);
      bool is_socket(const path& p, error_code& ec);
      (2)(filesystem TS)

      Checks if the given file status or path corresponds to a named IPC socket, as if determined by the POSIXS_IFSOCK.

      1) Equivalent tos.type()== file_type::socket.
      2) Equivalent tois_socket(status(p)) oris_socket(status(p, ec)).

      Contents

      [edit]Parameters

      s - file status to check
      p - path to examine
      ec - out-parameter for error reporting in the non-throwing overload

      [edit]Return value

      true if the file indicated byp or if the type indicateds refers to a named socket. The non-throwing overload returnsfalse if an error occurs.

      [edit]Exceptions

      1)
      noexcept specification:  
      noexcept
        
      2) The overload that does not take anerror_code& parameter throwsfilesystem_error on underlying OS API errors, constructed withp 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 anerror_code& parameter sets it to the OS API error code if an OS API call fails, and executesec.clear() if no errors occur. This overload has
      noexcept specification:  
      noexcept
        

      [edit]Notes

      Named sockets are UNIX domain sockets constructed withsocket andbind POSIX APIs, which may be used for advanced interprocess communication. In particular, they may be used to transport open file descriptors from one running process to another.

      The information provided by this function is usually also provided as a byproduct of directory iteration. During directory iteration, callingis_socket(*iterator) is less efficient thanis_socket(iterator->status()).

      [edit]Example

      Run this code
      #include <cstdio>#include <cstring>#include <experimental/filesystem>#include <fstream>#include <iostream>#include <sys/socket.h>#include <sys/stat.h>#include <sys/un.h>#include <unistd.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 accessorsfor(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

      [edit]See also

      determines file attributes
      determines file attributes, checking the symlink target
      (function)[edit]
      represents file type and permissions
      (class)[edit]
      checks whether file status is known
      (function)[edit]
      checks whether the given path refers to block device
      (function)[edit]
      checks whether the given path refers to a character device
      (function)[edit]
      checks whether the given path refers to a directory
      (function)[edit]
      checks whether the given path refers to a named pipe
      (function)[edit]
      checks whether the argument refers to another file
      (function)[edit]
      checks whether the argument refers to a regular file
      (function)[edit]
      checks whether the argument refers to a symbolic link
      (function)[edit]
      checks whether path refers to existing file system object
      (function)[edit]
      cached status of the file designated by this directory entry
      cached symlink_status of the file designated by this directory entry
      (public member function ofstd::experimental::filesystem::directory_entry)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/experimental/fs/is_socket&oldid=169732"

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