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      std::experimental::filesystem::is_symlink

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

      Checks if the given file status or path corresponds to a symbolic link, as if determined by the POSIXS_IFLNK.

      1) Equivalent tos.type()== file_type::symlink.
      2) Equivalent tois_symlink(status(p)) oris_symlink(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 symbolic link. 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

      The information provided by this function is usually also provided as a byproduct of directory iteration. During directory iteration, callingis_symlink(*iterator) is less efficient thanis_symlink(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 named IPC socket
      (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_symlink&oldid=169731"

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