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# QGList Class Reference

The QGList class is an internal class for implementing Qt collection classes. More...

`#include <qglist.h>`

Inherits QCollection.

Inherited by QList, QQueue and QStack.

List of all member functions.

## Public Members

- virtual uint count () const (internal)
- QDataStream& read ( QDataStream & ) (internal)
- QDataStream& write ( QDataStream & ) const (internal)

## Protected Members

- QGList () (internal)
- QGList ( const QGList & ) (internal)
- virtual ~QGList () (internal)
- QGList& operator= ( const QGList & ) (internal)
- bool operator== ( const QGList & ) const
- void inSort ( QCollection::Item ) (internal)
- void append ( QCollection::Item ) (internal)
- bool insertAt ( uint index, QCollection::Item ) (internal)
- void relinkNode ( QLNode * ) (internal)
- bool removeNode ( QLNode * ) (internal)
- bool remove ( QCollection::Item = 0 ) (internal)
- bool removeRef ( QCollection::Item = 0 ) (internal)
- bool removeFirst () (internal)
- bool removeLast () (internal)
- bool removeAt ( uint index ) (internal)
- QCollection::Item takeNode ( QLNode * ) (internal)
- QCollection::Item take () (internal)
- QCollection::Item takeAt ( uint index ) (internal)
- QCollection::Item takeFirst () (internal)
- QCollection::Item takeLast () (internal)
- void sort ()
- virtual void clear () (internal)
- int findRef ( QCollection::Item, bool = TRUE ) (internal)
- int find ( QCollection::Item, bool = TRUE ) (internal)
- uint containsRef ( QCollection::Item ) const (internal)
- uint contains ( QCollection::Item ) const (internal)
- QCollection::Item at ( uint index ) (internal)
- int at () const (internal)
- QLNode* currentNode () const (internal)
- QCollection::Item get () const (internal)
- QCollection::Item cfirst () const (internal)
- QCollection::Item clast () const (internal)
- QCollection::Item first () (internal)
- QCollection::Item last () (internal)
- QCollection::Item next () (internal)
- QCollection::Item prev () (internal)
- void toVector ( QGVector * ) const (internal)
- virtual int compareItems ( QCollection::Item, QCollection::Item )
- virtual QDataStream& read ( QDataStream &, QCollection::Item & )
- virtual QDataStream& write ( QDataStream &, QCollection::Item ) const

## Detailed Description

The QGList class is an internal class for implementing Qt collection classes.

QGList is a strictly internal class that acts as a base class for several collection classes; QList, QQueue and QStack.

QGList has some virtual functions that can be reimplemented to customize the subclasses.

- compareItems() compares two collection/list items.
- read() reads a collection/list item from a QDataStream.
- write() writes a collection/list item to a QDataStream.

Normally, you do not have to reimplement any of these functions. If you still want to reimplement them, see the QStrList class (qstrlist.h), which is a good example.

## Member Function Documentation

### int QGList::compareItems ( QCollection::Item item1, QCollection::Item item2 ) `[virtual protected]`

This virtual function compares two list items.

Returns:

- 0 if item1 == item2
- non-zero if item1 != item2

This function returns int rather than bool so that reimplementations can return three values and use it to sort by:

- 0 if item1 == item2
- > 0 (positive integer) if item1 > item2
- < 0 (negative integer) if item1 < item2

The QList::inSort() function requires that compareItems() is implemented as described here.

This function should not modify the list because some const functions call compareItems().

The default implementation compares the pointers:

### bool QGList::operator== ( const QGList & list ) const `[protected]`

Compares this list with list. Retruns TRUE if the lists contain the same data, else FALSE.

### QDataStream & QGList::read ( QDataStream & s, QCollection::Item & item ) `[virtual protected]`

Reads a collection/list item from the stream s and returns a reference to the stream.

The default implementation sets item to 0.

See also write().

### void QGList::sort () `[protected]`

Sorts the list by the result of the virtual compareItems() function.

The Heap-Sort algorithm is used for sorting. It sorts n items with O(n*log n) compares. This is the asymptotic optimal solution of the sorting problem.

### QDataStream & QGList::write ( QDataStream & s, QCollection::Item ) const `[virtual protected]`

Writes a collection/list item to the stream s and returns a reference to the stream.

The default implementation does nothing.

See also read().

### QGList::QGList () `[protected]`

For internal use only.

### QGList::QGList ( const QGList & list ) `[protected]`

For internal use only.

### QGList::~QGList () `[virtual protected]`

For internal use only.

### void QGList::append ( QCollection::Item d ) `[protected]`

For internal use only.

### QCollection::Item QGList::at( uint index ) `[protected]`

For internal use only.

### int QGList::at () const `[protected]`

For internal use only.

### QCollection::Item QGList::cfirst() const `[protected]`

For internal use only.

### QCollection::Item QGList::clast() const `[protected]`

For internal use only.

### void QGList::clear () `[virtual protected]`

For internal use only.

Reimplemented from QCollection.

### uint QGList::contains ( QCollection::Item d ) const `[protected]`

For internal use only.

### uint QGList::containsRef ( QCollection::Item d ) const `[protected]`

For internal use only.

### uint QGList::count () const `[virtual]`

For internal use only.

Reimplemented from QCollection.

### QLNode * QGList::currentNode () const `[protected]`

For internal use only.

### int QGList::find ( QCollection::Item d, bool fromStart = TRUE ) `[protected]`

For internal use only.

### int QGList::findRef ( QCollection::Item d, bool fromStart = TRUE ) `[protected]`

For internal use only.

### QCollection::Item QGList::first() `[protected]`

For internal use only.

### QCollection::Item QGList::get() const `[protected]`

For internal use only.

### void QGList::inSort ( QCollection::Item d ) `[protected]`

For internal use only.

### bool QGList::insertAt ( uint index, QCollection::Item d ) `[protected]`

For internal use only.

### QCollection::Item QGList::last() `[protected]`

For internal use only.

### QCollection::Item QGList::next() `[protected]`

For internal use only.

### QGList& QGList::operator= ( const QGList & list ) `[protected]`

For internal use only.

### QCollection::Item QGList::prev() `[protected]`

For internal use only.

### QDataStream & QGList::read ( QDataStream & s )

For internal use only.

### void QGList::relinkNode ( QLNode * n ) `[protected]`

For internal use only.

### bool QGList::remove ( QCollection::Item d = 0 ) `[protected]`

For internal use only.

### bool QGList::removeAt ( uint index ) `[protected]`

For internal use only.

### bool QGList::removeFirst () `[protected]`

For internal use only.

### bool QGList::removeLast () `[protected]`

For internal use only.

### bool QGList::removeNode ( QLNode * n ) `[protected]`

For internal use only.

### bool QGList::removeRef ( QCollection::Item d = 0 ) `[protected]`

For internal use only.

### QCollection::Item QGList::take() `[protected]`

For internal use only.

### QCollection::Item QGList::takeAt( uint index ) `[protected]`

For internal use only.

### QCollection::Item QGList::takeFirst() `[protected]`

For internal use only.

### QCollection::Item QGList::takeLast() `[protected]`

For internal use only.

### QCollection::Item QGList::takeNode( QLNode * n ) `[protected]`

For internal use only.

### void QGList::toVector ( QGVector * vector ) const `[protected]`

For internal use only.

### QDataStream & QGList::write ( QDataStream & s ) const

For internal use only.

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