std::filesystem::directory_entry::exists

 

C++

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Standard library

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

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Ranges library (C++20)

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Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

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::perm_options filesystem::copy_options filesystem::directory_options filesystem::file_time_type
Functions
filesystem::absolute filesystem::canonicalfilesystem::weakly_canonical filesystem::relativefilesystem::proximate 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

 

std::filesystem::directory_entry

Member functions

directory_entry::directory_entry

Modifiers

directory_entry::operator=

directory_entry::assign

directory_entry::replace_filename

directory_entry::refresh

Observers

directory_entry::pathdirectory_entry::operator const path&

directory_entry::exists

directory_entry::is_block_file

directory_entry::is_character_file

directory_entry::is_directory

directory_entry::is_fifo

directory_entry::is_other

directory_entry::is_regular_file

directory_entry::is_socket

directory_entry::is_symlink

directory_entry::file_size

directory_entry::hard_link_count

directory_entry::last_write_time

directory_entry::statusdirectory_entry::symlink_status

directory_entry::operator==directory_entry::operator!=directory_entry::operator<directory_entry::operator>directory_entry::operator<=directory_entry::operator>=directory_entry::operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Non-member functions

operator<<

 

bool exists() const;	(1)	(since C++17)
bool exists( std::error_code& ec ) const noexcept;	(2)	(since C++17)

Checks whether the pointed-to object exists. Effectively returns:

1) std::filesystem::exists(status()),

2) std::filesystem::exists(status(ec)).

Note that status() follows symlinks to their targets.

Parameters

ec

-

out-parameter for error reporting in the non-throwing overload

Return value

true if the referred-to filesystem object exists.

Exceptions

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.

1) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.

2) Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur.

Example

Run this code

#include <filesystem>
#include <iostream>
 
int main()
{
    for (auto const str:
    {
        "/usr/bin/cat",
        "/usr/bin/mouse",
        "/usr/bin/python",
        "/usr/bin/bison",
        "/usr/bin/yacc",
        "/usr/bin/c++",
    })
    {
        std::filesystem::directory_entry entry{str};
 
        std::cout << "directory entry " << entry
                  << (entry.exists() ? " exists\n" : " does not exist\n");
    }
}

Possible output:

// Output on a POSIX system:
directory entry "/usr/bin/cat" exist
directory entry "/usr/bin/mouse" does not exist
directory entry "/usr/bin/python" exists
directory entry "/usr/bin/bison" exists
directory entry "/usr/bin/yacc" does not exist
directory entry "/usr/bin/c++" exists

See also

exists (C++17)

checks whether path refers to existing file system object (function)