# std::filesystem::directory_iterator

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< cpp‎ | filesystem

Defined in header `<filesystem>` |  |
class directory_iterator; |  | (since C++17)

`directory_iterator` is a LegacyInputIterator that iterates over the `directory_entry` elements of a directory (but does not visit the subdirectories). The iteration order is unspecified, except that each directory entry is visited only once. The special pathnames dot and dot-dot are skipped.

If the `directory_iterator` reports an error or is advanced past the last directory entry, it becomes equal to the default-constructed iterator, also known as the end iterator. Two end iterators are always equal, dereferencing or incrementing the end iterator is undefined behavior.

If a file or a directory is deleted or added to the directory tree after the directory iterator has been created, it is unspecified whether the change would be observed through the iterator.

### Member types

Member type | Definition
`value_type` | std::filesystem::directory_entry
`difference_type` | std::ptrdiff_t
`pointer` | const std::filesystem::directory_entry*
`reference` | const std::filesystem::directory_entry&
`iterator_category` | std::input_iterator_tag

### Member functions

(constructor) | constructs a directory iterator (public member function)
(destructor) | default destructor (public member function)
operator= | assigns contents (public member function)
operator*operator-> | accesses the pointed-to entry (public member function)
increment operator++ | advances to the next entry (public member function)

### Non-member functions

begin(std::filesystem::directory_iterator)end(std::filesystem::directory_iterator) | range-based for loop support (function)

Additionally, `operator==` and `operator!=` are provided, either as members or as non-members, as required by LegacyInputIterator

### Notes

Many low-level OS APIs for directory traversal retrieve file attributes along with the next directory entry. The constructors and the non-const member functions of `directory_iterator` store these attributes, if any, in the pointed-to `directory_entry` without calling `directory_entry::refresh`, which makes it possible to examine the attributes of the directory entries as they are being iterated over, without making additional system calls.

### Example

Run this code

    #include <fstream>
    #include <iostream>
    #include <filesystem>
    namespace fs = std::filesystem;

    int main()
    {
        fs::create_directories("sandbox/a/b");
        std::ofstream("sandbox/file1.txt");
        std::ofstream("sandbox/file2.txt");
        for(auto& p: fs::directory_iterator("sandbox"))
            std::cout << p.path() << '\n';
        fs::remove_all("sandbox");
    }

Possible output:

    "sandbox/a"
    "sandbox/file1.txt"
    "sandbox/file2.txt"

### See also

recursive_directory_iterator (C++17) | an iterator to the contents of a directory and its subdirectories (class)
directory_options (C++17) | options for iterating directory contents (enum)
directory_entry (C++17) | a directory entry (class)

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