std::filesystem::directory_iterator - cppreference.com (original) (raw)

std::filesystem::directory_iterator

| | | | | -------------------------- | | ------------- | | 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.

Contents

• 1 Member types
• 2 Member functions
• 3 Non-member functions
• 4 Helper specializations
• 5 Notes
• 6 Example
• 7 Defect reports
• 8 See also

[edit] Member types

[edit] Member functions

[edit] Non-member functions

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-member.

[edit] Helper specializations

These specializations for directory_iterator make it a borrowed_range and a view.

[edit] 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.

[edit] Example

Possible output:

directory_iterator: "sandbox/file2.txt" "sandbox/file1.txt" "sandbox/dir1"   directory_iterator as a range: "sandbox/file2.txt" "sandbox/file1.txt" "sandbox/dir1"   recursive_directory_iterator: "sandbox/file2.txt" "sandbox/file1.txt" "sandbox/dir1" "sandbox/dir1/dir2"

[edit] Defect reports

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

[edit] See also