recursive_directory_iterator is aLegacyInputIterator that iterates over thedirectory_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 optionfollow_directory_symlink at construction time.

The special pathnamesdot anddot-dot are skipped.

If therecursive_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 undefined 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.

[edit]Member types

[edit]Member functions

[edit]Non-member functions

Additionally,operator== andoperator!= are(until C++20)operator== is(since C++20) provided as required byLegacyInputIterator.

It is unspecifiedwhetheroperator!= is provided because it can be synthesized fromoperator==, and(since C++20) whether an equality operator is a member or non-member.

[edit]Helper specializations

These specializations forrecursive_directory_iterator make it aborrowed_range and aview.

[edit]Notes

Arecursive_directory_iterator typically holds a reference-countedpointer (to satisfy shallow-copy semantics ofLegacyInputIterator) to an implementation object, which holds:

• a container (such asstd::vector) of non-recursivedirectory_iterators that forms the recursion stack,
• the recursion depth counter (accessible withdepth()),
• the directory options used at construction (accessible withoptions()),
• the pending recursion flag (accessible withrecursion_pending(), may be combined with the directory options to save space).

[edit]Example

#include <filesystem>#include <fstream>#include <iostream>#include <string>namespace fs= std::filesystem; int main(){std::filesystem::current_path(std::filesystem::temp_directory_path());std::filesystem::create_directories("sandbox/a/b");std::ofstream("sandbox/file1.txt");std::filesystem::create_symlink("a","sandbox/syma"); // Iterate over the std::filesystem::directory_entry elements explicitlyauto entry_length{3UZ};for(const fs::directory_entry& dir_entry:            fs::recursive_directory_iterator("sandbox")){std::cout<< dir_entry<<'\n';if(auto l{dir_entry.path().string().length()}; entry_length< l)            entry_length= l;}std::cout<<std::string(entry_length+2,'-')<<'\n'; // Iterate over the std::filesystem::directory_entry elements using `auto`for(autoconst& dir_entry: fs::recursive_directory_iterator("sandbox"))std::cout<< dir_entry<<'\n'; std::filesystem::remove_all("sandbox");}

"sandbox/syma""sandbox/file1.txt""sandbox/a""sandbox/a/b"-------------------"sandbox/syma""sandbox/file1.txt""sandbox/a""sandbox/a/b"

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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