W3cubDocs

/C++

std::filesystem::directory_iterator

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

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

Non-member functions

begin(std::filesystem::directory_iterator)end(std::filesystem::directory_iterator)

range-based for loop support
(function)

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

#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"