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

 

C++

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Technical specifications

Symbols index

External libraries

 

Experimental

Technical Specification

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

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Extensions for parallelism 2 (parallelism TS v2)

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Filesystem library

Classes
filesystem::path filesystem::filesystem_error filesystem::directory_entry filesystem::directory_iterator filesystem::recursive_directory_iterator filesystem::file_status	filesystem::space_info filesystem::file_type filesystem::perms filesystem::copy_options filesystem::directory_options filesystem::file_time_type
Functions
filesystem::absolute filesystem::system_complete filesystem::canonical filesystem::copy filesystem::copy_file filesystem::copy_symlink filesystem::create_directory filesystem::create_directories filesystem::create_hard_link filesystem::create_symlink filesystem::create_directory_symlink filesystem::current_path filesystem::exists filesystem::equivalent	filesystem::file_size filesystem::hard_link_count filesystem::last_write_time filesystem::permissions filesystem::read_symlink filesystem::remove filesystem::remove_all filesystem::rename filesystem::resize_file filesystem::space filesystem::status filesystem::symlink_status filesystem::temp_directory_path
File types
filesystem::is_block_file filesystem::is_character_file filesystem::is_directory filesystem::is_empty filesystem::status_known	filesystem::is_fifo filesystem::is_other filesystem::is_regular_file filesystem::is_socket filesystem::is_symlink

 

Defined in header <experimental/filesystem>
file_status status( const path& p ); file_status status( const path& p, error_code& ec ) noexcept;	(1)	(filesystem TS)
file_status symlink_status( const path& p ); file_status symlink_status( const path& p, error_code& ec ) noexcept;	(2)	(filesystem TS)

1) Determines the type and attributes of the filesystem object identified by p as if by POSIX stat (symlinks are followed to their targets).

• If p is a regular file, returns file_status(file_type::regular).
• If p is a directory, returns file_status(file_type::directory).
• If p is a block special file, returns file_status(file_type::block).
• If p is a character special file, returns file_status(file_type::character).
• If p is a fifo or pipe file, returns file_status(file_type::fifo).
• If p is a socket, returns file_status(file_type::socket).
• If p does not exist, returns file_status(file_type::not_found).
• If p exists but file attributes cannot be determined, e.g. due to lack of permissions, returns file_status(file_type::unknown).
• If errors prevent even knowing whether p exists, the non-throwing overload sets ec and returns file_status(file_type::none), and the throwing overload throws filesystem_error.
• Otherwise, returns file_status(file_type::unknown).

2) Same as (1) except that the behavior is as if the POSIX lstat is used (symlinks are not followed):

• If p is a symlink, returns file_status(file_type::symlink).

Parameters

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

Return value

The file status (a file_status object).

Exceptions

The overload that does not take an 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 an 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 information provided by this function is usually also provided as a byproduct of directory iteration, and may be obtained by the member functions of directory_entry. During directory iteration, calling status again is unnecessary.

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 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

file_status	represents file type and permissions (class)
status_known	checks whether file status is known (function)
is_block_file	checks whether the given path refers to block device (function)
is_character_file	checks whether the given path refers to a character device (function)
is_directory	checks whether the given path refers to a directory (function)
is_fifo	checks whether the given path refers to a named pipe (function)
is_other	checks whether the argument refers to an other file (function)
is_regular_file	checks whether the argument refers to a regular file (function)
is_socket	checks whether the argument refers to a named IPC socket (function)
is_symlink	checks whether the argument refers to a symbolic link (function)
exists	checks whether path refers to existing file system object (function)
statussymlink_status	cached status of the file designated by this directory entry cached symlink_status of the file designated by this directory entry (public member function of std::experimental::filesystem::directory_entry)