std::filesystem::directory_iterator::directory_iterator
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                    < cpp | filesystem | directory iterator
                    
                                                            
                    | directory_iterator() noexcept; | (1) | (since C++17) | 
| explicit directory_iterator( const std::filesystem::path& p ); | (2) | (since C++17) | 
| directory_iterator( const std::filesystem::path& p,  std::filesystem::directory_options options); | (3) | (since C++17) | 
| directory_iterator( const std::filesystem::path& p, std::error_code& ec ); | (4) | (since C++17) | 
| directory_iterator( const std::filesystem::path& p,                      std::filesystem::directory_options options, | (5) | (since C++17) | 
| directory_iterator( const directory_iterator& ) = default; | (6) | (since C++17) | 
| directory_iterator( directory_iterator&& ) = default; | (7) | (since C++17) | 
Constructs a new directory iterator.
1) Constructs the end iterator.
2) Constructs a directory iterator that refers to the first directory entry of a directory identified by 
p. If p refers to an non-existing file or not a directory, throws std::filesystem::filesystem_error.3) Same as (2), but if std::filesystem::directory_options::skip_permission_denied is set in 
options and construction encounters a permissions denied error, constructs the end iterator and does not report an error.4) Constructs a directory iterator that refers to the first directory entry of a directory identified by 
p. If p refers to an non-existing file or not a directory, returns the end iterator and sets ec.5) Same as (4), but if std::filesystem::directory_options::skip_permission_denied is set in 
options and construction encounters a permissions denied error, constructs the end iterator and does not report an error.Parameters
| This section is incomplete | 
Exceptions
2-5) The overload that does not take a std::error_code& parameter throws filesystem_error on underlying OS API errors, constructed with 
p as the first path argument and the OS error code as the error code argument. The overload taking a std::error_code& parameter sets it to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur. Any overload not marked noexcept may throw  std::bad_alloc if memory allocation fails.Notes
To iterate over the current directory, construct the iterator as directory_iterator(".") instead of directory_iterator("").
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior | 
|---|---|---|---|
| LWG 3013 | C++17 | error_codeoverload marked noexcept but can allocate memory | noexcept removed |