QDirIterator Class | Qt Core 6.1.3

- Qt 6.1
- Qt Core
- C++ Classes
- QDirIterator
- Qt 6.1.3 Reference Documentation

# QDirIterator Class

The QDirIterator class provides an iterator for directory entrylists. More...

Header: | #include <QDirIterator>
CMake: | find_package(Qt6 COMPONENTS Core REQUIRED) target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake: | QT += core

- List of all members, including inherited members

## Public Types

enum | IteratorFlag { NoIteratorFlags, Subdirectories, FollowSymlinks }
flags | IteratorFlags

## Public Functions

| QDirIterator(const QString &path, const QStringList &nameFilters, QDir::Filters filters = QDir::NoFilter, QDirIterator::IteratorFlags flags = NoIteratorFlags)
| QDirIterator(const QString &path, QDir::Filters filters, QDirIterator::IteratorFlags flags = NoIteratorFlags)
| QDirIterator(const QString &path, QDirIterator::IteratorFlags flags = NoIteratorFlags)
| QDirIterator(const QDir &dir, QDirIterator::IteratorFlags flags = NoIteratorFlags)
| ~QDirIterator()
QFileInfo | fileInfo() const
QString | fileName() const
QString | filePath() const
bool | hasNext() const
QString | next()
QString | path() const

## Detailed Description

You can use QDirIterator to navigate entries of a directory one at a time. It is similar to QDir::entryList() and QDir::entryInfoList(), but because it lists entries one at a time instead of all at once, it scales better and is more suitable for large directories. It also supports listing directory contents recursively, and following symbolic links. Unlike QDir::entryList(), QDirIterator does not support sorting.

The QDirIterator constructor takes a QDir or a directory as argument. After construction, the iterator is located before the first directory entry. Here's how to iterate over all the entries sequentially:

     QDirIterator it("/etc", QDirIterator::Subdirectories);
     while (it.hasNext()) {
         qDebug() << it.next();

         // /etc/.
         // /etc/..
         // /etc/X11
         // /etc/X11/fs
         // ...
     }

Here's how to find and read all files filtered by name, recursively:

     QDirIterator it("/sys", QStringList() << "scaling_cur_freq", QDir::NoFilter, QDirIterator::Subdirectories);
     while (it.hasNext()) {
         QFile f(it.next());
         f.open(QIODevice::ReadOnly);
         qDebug() << f.fileName() << f.readAll().trimmed().toDouble() / 1000 << "MHz";
     }

The next() function returns the path to the next directory entry and advances the iterator. You can also call filePath() to get the current file path without advancing the iterator. The fileName() function returns only the name of the file, similar to how QDir::entryList() works. You can also call fileInfo() to get a QFileInfo for the current entry.

Unlike Qt's container iterators, QDirIterator is uni-directional (i.e., you cannot iterate directories in reverse order) and does not allow random access.

See also QDir and QDir::entryList().

## Member Type Documentation

### enum QDirIterator::IteratorFlag
flags QDirIterator::IteratorFlags

This enum describes flags that you can combine to configure the behavior of QDirIterator.

Constant | Value | Description
--- | --- | ---
`QDirIterator::NoIteratorFlags` | `0x0` | The default value, representing no flags. The iterator will return entries for the assigned path.
`QDirIterator::Subdirectories` | `0x2` | List entries inside all subdirectories as well.
`QDirIterator::FollowSymlinks` | `0x1` | When combined with Subdirectories, this flag enables iterating through all subdirectories of the assigned path, following all symbolic links. Symbolic link loops (e.g., "link" => "." or "link" => "..") are automatically detected and ignored.

The IteratorFlags type is a typedef for QFlags<IteratorFlag>. It stores an OR combination of IteratorFlag values.

## Member Function Documentation

### QDirIterator::QDirIterator(const QString &path, const QStringList &nameFilters, QDir::Filters filters = QDir::NoFilter, QDirIterator::IteratorFlags flags = NoIteratorFlags)

Constructs a QDirIterator that can iterate over path, using nameFilters and filters. You can pass options via flags to decide how the directory should be iterated.

By default, flags is NoIteratorFlags, which provides the same behavior as QDir::entryList().

For example, the following iterator could be used to iterate over audio files:

     QDirIterator audioFileIt(audioPath, {"*.mp3", "*.wav"}, QDir::Files);

Note: To list symlinks that point to non existing files, QDir::System must be passed to the flags.

See also hasNext(), next(), IteratorFlags, and QDir::setNameFilters().

### QDirIterator::QDirIterator(const QString &path, QDir::Filters filters, QDirIterator::IteratorFlags flags = NoIteratorFlags)

Constructs a QDirIterator that can iterate over path, with no name filtering and filters for entry filtering. You can pass options via flags to decide how the directory should be iterated.

By default, filters is QDir::NoFilter, and flags is NoIteratorFlags, which provides the same behavior as in QDir::entryList().

Note: To list symlinks that point to non existing files, QDir::System must be passed to the flags.

See also hasNext(), next(), and IteratorFlags.

### QDirIterator::QDirIterator(const QString &path, QDirIterator::IteratorFlags flags = NoIteratorFlags)

Constructs a QDirIterator that can iterate over path. You can pass options via flags to decide how the directory should be iterated.

By default, flags is NoIteratorFlags, which provides the same behavior as in QDir::entryList().

Note: To list symlinks that point to non existing files, QDir::System must be passed to the flags.

See also hasNext(), next(), and IteratorFlags.

### QDirIterator::QDirIterator(const QDir &dir, QDirIterator::IteratorFlags flags = NoIteratorFlags)

Constructs a QDirIterator that can iterate over dir's entrylist, using dir's name filters and regular filters. You can pass options via flags to decide how the directory should be iterated.

By default, flags is NoIteratorFlags, which provides the same behavior as in QDir::entryList().

The sorting in dir is ignored.

Note: To list symlinks that point to non existing files, QDir::System must be passed to the flags.

See also hasNext(), next(), and IteratorFlags.

### QDirIterator::~QDirIterator()

Destroys the QDirIterator.

### QFileInfo QDirIterator::fileInfo() const

Returns a QFileInfo for the current directory entry.

See also filePath() and fileName().

### QString QDirIterator::fileName() const

Returns the file name for the current directory entry, without the path prepended.

This function is convenient when iterating a single directory. When using the QDirIterator::Subdirectories flag, you can use filePath() to get the full path.

See also filePath() and fileInfo().

### QString QDirIterator::filePath() const

Returns the full file path for the current directory entry.

See also fileInfo() and fileName().

### bool QDirIterator::hasNext() const

Returns `true` if there is at least one more entry in the directory; otherwise, false is returned.

See also next(), fileName(), filePath(), and fileInfo().

### QString QDirIterator::next()

Advances the iterator to the next entry, and returns the file path of this new entry. If hasNext() returns `false`, this function does nothing, and returns an empty QString.

You can call fileName() or filePath() to get the current entry file name or path, or fileInfo() to get a QFileInfo for the current entry.

See also hasNext(), fileName(), filePath(), and fileInfo().

### QString QDirIterator::path() const

Returns the base directory of the iterator.