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std::filesy...ory_iterator(3) C++ Standard Libarystd::filesy...ory_iterator(3) NAME std::filesystem::recursive_directory_iterator - std::filesystem::recur- sive_directory_iterator Synopsis Defined in header <filesystem> class recursive_directory_iterator; (since C++17) recursive_directory_iterator is a LegacyInputIterator that iterates over the directory_entry elements of a directory, and, recursively, over the entries of all subdirectories. The iteration order is unspecified, except that each directory entry is visited only once. By default, symlinks are not followed, but this can be enabled by specifying the directory option follow_directory_symlink at construction time. The special pathnames dot and dot-dot are skipped. If the recursive_directory_iterator reports an error or is advanced past the last directory entry of the top-level directory, 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 un- defined behavior. If a file or a directory is deleted or added to the directory tree after the recursive directory iterator has been created, it is unspecified whether the change would be observed through the iterator. If the directory structure contains cycles, the end iterator may be unreachable. 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 recursive directory iterator (public member function) destructor default destructor (public member function) Observers operator* accesses the pointed-to entry operator-> (public member function) returns the currently active options that affect the options iteration (public member function) depth returns the current recursion depth (public member function) checks whether the recursion is disabled for the current recursion_pending directory (public member function) Modifiers operator= assigns contents (public member function) increment advances to the next entry operator++ (public member function) pop moves the iterator one level up in the di- rectory hierarchy (public member function) disable_recursion_pending disables recursion until the next incre- ment (public member function) Non-member functions begin(std::filesystem::recursive_directory_iterator) range-based for loop support end(std::filesystem::recursive_directory_iterator) (function) Additionally, operator== and operator!= are (until C++20) operator== is (since C++20) provided as required by LegacyInputIterator. It is unspecified whether operator!= is provided because it can be synthesized from operator==, and (since C++20) whether an equality operator is a member or non-mem- ber. Helper templates namespace std::ranges { template<> inline constexpr bool (since enable_borrowed_range<std::filesystem::recursive_directory_iterator> = C++20) true; } namespace std::ranges { template<> (since inline constexpr bool C++20) enable_view<std::filesystem::recursive_directory_iterator> = true; } These specializations for recursive_directory_iterator make it a borrowed_range and a view. Notes A recursive_directory_iterator typically holds a reference-counted pointer (to satisfy shallow-copy semantics of LegacyInputIterator) to an imple- mentation object, which holds: * a container (such as std::vector) of non-recursive directory_it- erators that forms the recursion stack * the recursion depth counter (accessible with depth()) * the directory options used at construction (accessible with op- tions()) * the pending recursion flag (accessible with recursion_pending(), may be combined with the directory options to save space) Example // Run this code #include <fstream> #include <iostream> #include <filesystem> namespace fs = std::filesystem; int main() { fs::current_path(fs::temp_directory_path()); fs::create_directories("sandbox/a/b"); std::ofstream("sandbox/file1.txt"); fs::create_symlink("a", "sandbox/syma"); // Iterate over the `std::filesystem::directory_entry` elements explicitly for (const fs::directory_entry& dir_entry : fs::recursive_directory_iterator("sandbox")) { std::cout << dir_entry << '\n'; } std::cout << "-----------------------------\n"; // Iterate over the `std::filesystem::directory_entry` elements using `auto` for (auto const& dir_entry : fs::recursive_directory_itera- tor("sandbox")) { std::cout << dir_entry << '\n'; } fs::remove_all("sandbox"); } Possible output: "sandbox/syma" "sandbox/file1.txt" "sandbox/a" "sandbox/a/b" ----------------------------- "sandbox/syma" "sandbox/file1.txt" "sandbox/a" "sandbox/a/b" Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Correct behavior LWG 3480 C++20 recursive_directory_iterator was neither a it is both borrowed_range nor a view See also directory_iterator an iterator to the contents of the directory (C++17) (class) directory_entry a directory entry (C++17) (class) directory_options options for iterating directory contents (C++17) (enum) http://cppreference.com 2022.07.31 std::filesy...ory_iterator(3)
NAME | Synopsis | Member types | Member functions | Observers | Modifiers | Non-member functions | Notes | Example | Possible output: | See also
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