Section
std::filesystem::directory_iterator
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.
# Declarations
class directory_iterator;
(since C++17)
# 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 std::filesystem::directory_iterator store these attributes, if any, in the pointed-to std::filesystem::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
#include <algorithm>
#include <filesystem>
#include <fstream>
#include <iostream>
int main()
{
const std::filesystem::path sandbox{"sandbox"};
std::filesystem::create_directories(sandbox/"dir1"/"dir2");
std::ofstream{sandbox/"file1.txt"};
std::ofstream{sandbox/"file2.txt"};
std::cout << "directory_iterator:\n";
// directory_iterator can be iterated using a range-for loop
for (auto const& dir_entry : std::filesystem::directory_iterator{sandbox})
std::cout << dir_entry.path() << '\n';
std::cout << "\ndirectory_iterator as a range:\n";
// directory_iterator behaves as a range in other ways, too
std::ranges::for_each(
std::filesystem::directory_iterator{sandbox},
[](const auto& dir_entry) { std::cout << dir_entry << '\n'; });
std::cout << "\nrecursive_directory_iterator:\n";
for (auto const& dir_entry : std::filesystem::recursive_directory_iterator{sandbox})
std::cout << dir_entry << '\n';
// delete the sandbox dir and all contents within it, including subdirs
std::filesystem::remove_all(sandbox);
}
# Defect reports
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 3480 | C++20 | directory_iterator was neither a borrowed_range nor a view | it is both |