std::filesystem::directory_iterator (3) - Linux Manuals

std::filesystem::directory_iterator: std::filesystem::directory_iterator

NAME

std::filesystem::directory_iterator - std::filesystem::directory_iterator

Synopsis

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

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

Non-member functions

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

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"