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      std::filesystem::status,std::filesystem::symlink_status

      From cppreference.com
      <cpp‎ |filesystem
       
       
      Filesystem library
      Classes
      Functions
      File types
       
      Defined in header<filesystem>
      (1)(since C++17)
      std::filesystem::file_status status(conststd::filesystem::path& p,
                                           std::error_code& ec)noexcept;
      		 (2)(since C++17)
      (3)(since C++17)
      std::filesystem::file_status symlink_status(conststd::filesystem::path& p,
                                                   std::error_code& ec)noexcept;
      		 (4)(since C++17)
      1,2) Determines the type and attributes of the filesystem object identified byp as if by POSIXstat (symlinks are followed to their targets). In the following description,prms is the result of(m& perms::mask), wherem is obtained as if by takingst_mode from the POSIXstruct stat and converting it to the typestd::filesystem::perms.
      • Ifp is a regular file (as if by POSIXS_ISREG), returnsfile_status(file_type::regular, prms).
      • Ifp is a directory (as if by POSIXS_ISDIR), returnsfile_status(file_type::directory, prms).
      • Ifp is a block special file (as if by POSIXS_ISBLK), returnsfile_status(file_type::block, prms).
      • Ifp is a character special file (as if by POSIXS_ISCHR), returnsfile_status(file_type::character, prms).
      • Ifp is a fifo or pipe file (as if by POSIXS_ISFIFO), returnsfile_status(file_type::fifo, prms).
      • Ifp is a socket (as if by POSIXS_ISSOCK), returnsfile_status(file_type::socket, prms).
      • Ifp has an implementation-defined file type, returnsfile_status(file_type::A, prms) whereA is the implementation-definedfile_type constant for that type.
      • Ifp does not exist, returnsfile_status(file_type::not_found).
      • Ifp exists but file attributes cannot be determined, e.g. due to lack of permissions, returnsfile_status(file_type::unknown).
      • If errors prevent even knowing whetherp exists, the non-throwing overload setsec and returnsfile_status(file_type::none), and the throwing overload throwsfilesystem_error.
      • Otherwise, returnsfile_status(file_type::unknown, prms).
      3,4) Same as(1,2) except that the behavior is as if the POSIXlstat is used (symlinks are not followed):
      • Ifp is a symlink, returnsfile_status(file_type::symlink).

      Contents

      [edit]Parameters

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

      [edit]Return value

      The file status (afilesystem::file_status object).

      [edit]Exceptions

      Any overload not markednoexcept may throwstd::bad_alloc if memory allocation fails.

      1,3) Throwsstd::filesystem::filesystem_error on underlying OS API errors, constructed withp as the first path argument and the OS error code as the error code argument.
      2,4) Sets astd::error_code& parameter to the OS API error code if an OS API call fails, and executesec.clear() if no errors occur.

      [edit]Notes

      The information provided by this function is usually also provided as a byproduct of directory iteration, and may be obtained by the member functions offilesystem::directory_entry. During directory iteration, callingstatus again is unnecessary.

      [edit]Example

      Run this code
      #include <cstdio>#include <cstring>#include <filesystem>#include <fstream>#include <iostream>#include <sys/socket.h>#include <sys/stat.h>#include <sys/un.h>#include <unistd.h> namespace fs= std::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");    fs::create_directory("sandbox/dir");std::ofstream{"sandbox/file"};// create regular file    fs::create_symlink("file","sandbox/symlink");     mkfifo("sandbox/pipe",0644);    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,reinterpret_cast<sockaddr*>(&addr), sizeof addr); // 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 (prefer std::unique_ptr-based custom deleters)    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

      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]
      (C++17)
      		 checks whether the given path refers to a named pipe
      (function)[edit]
      (C++17)
      		 checks whether the argument refers to another file
      (function)[edit]
      checks whether the argument refers to a regular file
      (function)[edit]
      (C++17)
      		 checks whether the argument refers to a named IPC socket
      (function)[edit]
      (C++17)
      		 checks whether the argument refers to a symbolic link
      (function)[edit]
      (C++17)
      		 checks whether path refers to existing file system object
      (function)[edit]
      status of the file designated by this directory entry;
      status of the file/symlink designated by this directory entry
      (public member function ofstd::filesystem::directory_entry)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/filesystem/status&oldid=180242"
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