From cppreference.com
classrecursive_directory_iterator;(since C++17)recursive_directory_iterator is a
that iterates over the
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
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 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.
Member types
Member type Definition value_type
std::filesystem::directory_entry
difference_type
pointerconststd::filesystem::directory_entry*referenceconststd::filesystem::directory_entry&iterator_category
Member functions
constructs a recursive directory iterator
(public member function)
(destructor)
default destructor
(public member function)
Observers
accesses the pointed-to entry
(public member function)
returns the currently active options that affect the iteration
(public member function)
returns the current recursion depth
(public member function)
checks whether the recursion is disabled for the current directory
(public member function)
Modifiers
assigns contents
(public member function)
advances to the next entry
(public member function)
moves the iterator one level up in the directory hierarchy
(public member function)
disables recursion until the next increment
(public member function)
Non-member functions
Additionally, operator== and operator!= are(until C++20)operator== is(since C++20) provided as required by
.
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.
Helper specializations
template<>constexprboolranges::enable_borrowed_range<std::filesystem::recursive_directory_iterator>=true;(since C++20)template<>constexprboolranges::enable_view<std::filesystem::recursive_directory_iterator>=true;(since C++20)These specializations for recursive_directory_iterator make it a
and a
.
Notes
A recursive_directory_iterator typically holds a reference-counted pointer (to satisfy shallow-copy semantics of
) to an implementation object, which holds:
a container (such as
) of non-recursive
that forms the recursion stack,
the recursion depth counter (accessible with
),
the directory options used at construction (accessible with
),
the pending recursion flag (accessible with
, may be combined with the directory options to save space).
Example
Run this code
#include<filesystem>#include<fstream>#include<iostream>#include<string>namespacefs=std::filesystem;intmain(){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 explicitlyautoentry_length{3UZ};for(constfs::directory_entry&dir_entry:fs::recursive_directory_iterator("sandbox")){std::cout<<dir_entry<<'\n';if(autol{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");}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 retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
C++20 recursive_directory_iterator was neither a
nor a
it is both See also