const_iterator Class Reference
(QFuture::const_iterator)The QFuture::const_iterator class provides an STL-style const iterator for QFuture. More...
#include <QFuture>Note: All functions in this class are reentrant.
This class was introduced in Qt 4.4.
Public Types
| typedef | difference_type |
| typedef | iterator_category |
| typedef | pointer |
| typedef | reference |
| typedef | value_type |
Public Functions
| const_iterator () | |
| const_iterator ( const const_iterator & other ) | |
| bool | operator!= ( const const_iterator & other ) const |
| const T & | operator* () const |
| const_iterator | operator+ ( int j ) const |
| const_iterator & | operator++ () |
| const_iterator | operator++ ( int ) |
| const_iterator & | operator+= ( int j ) |
| const_iterator | operator- ( int j ) const |
| const_iterator & | operator-- () |
| const_iterator | operator-- ( int ) |
| const_iterator & | operator-= ( int j ) |
| const T * | operator-> () const |
| const_iterator & | operator= ( const const_iterator & other ) |
| bool | operator== ( const const_iterator & other ) const |
Detailed Description
The QFuture::const_iterator class provides an STL-style const iterator for QFuture.
QFuture provides both STL-style iterators and Java-style iterators. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity.
The default QFuture::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QFuture function like QFuture::constBegin() or QFuture::constEnd() before you start iterating. Here's a typical loop that prints all the results available in a future:
QFuture<QString> future = ...; QFuture<QString>::const_iterator i; for (i = future.constBegin(); i != future.constEnd(); ++i) cout << *i << endl;
See also QFutureIterator and QFuture.
Member Type Documentation
typedef const_iterator::difference_type
Typedef for ptrdiff_t. Provided for STL compatibility.
typedef const_iterator::iterator_category
Typedef for std::bidirectional_iterator_tag. Provided for STL compatibility.
typedef const_iterator::pointer
Typedef for const T *. Provided for STL compatibility.
typedef const_iterator::reference
Typedef for const T &. Provided for STL compatibility.
typedef const_iterator::value_type
Typedef for T. Provided for STL compatibility.
Member Function Documentation
const_iterator::const_iterator ()
Constructs an uninitialized iterator.
Functions like operator*() and operator++() should not be called on an uninitialized iterartor. Use operator=() to assign a value to it before using it.
See also QFuture::constBegin() and QFuture::constEnd().
const_iterator::const_iterator ( const const_iterator & other )
Constructs a copy of other.
bool const_iterator::operator!= ( const const_iterator & other ) const
Returns true if other points to a different result than this iterator; otherwise returns false.
See also operator==().
const T & const_iterator::operator* () const
Returns the current result.
const_iterator const_iterator::operator+ ( int j ) const
Returns an iterator to the results at j positions forward from this iterator. (If j is negative, the iterator goes backward.)
See also operator-() and operator+=().
const_iterator & const_iterator::operator++ ()
The prefix ++ operator (++it) advances the iterator to the next result in the future and returns an iterator to the new current result.
Calling this function on QFuture::constEnd() leads to undefined results.
See also operator--().
const_iterator const_iterator::operator++ ( int )
This is an overloaded function.
The postfix ++ operator (it++) advances the iterator to the next result in the future and returns an iterator to the previously current result.
const_iterator & const_iterator::operator+= ( int j )
Advances the iterator by j results. (If j is negative, the iterator goes backward.)
See also operator-=() and operator+().
const_iterator const_iterator::operator- ( int j ) const
Returns an iterator to the result at j positions backward from this iterator. (If j is negative, the iterator goes forward.)
See also operator+() and operator-=().
const_iterator & const_iterator::operator-- ()
The prefix -- operator (--it) makes the preceding result current and returns an iterator to the new current result.
Calling this function on QFuture::constBegin() leads to undefined results.
See also operator++().
const_iterator const_iterator::operator-- ( int )
This is an overloaded function.
The postfix -- operator (it--) makes the preceding result current and returns an iterator to the previously current result.
const_iterator & const_iterator::operator-= ( int j )
Makes the iterator go back by j results. (If j is negative, the iterator goes forward.)
See also operator+=() and operator-().
const T * const_iterator::operator-> () const
Returns a pointer to the current result.
const_iterator & const_iterator::operator= ( const const_iterator & other )
Assigns other to this iterator.
bool const_iterator::operator== ( const const_iterator & other ) const
Returns true if other points to the same result as this iterator; otherwise returns false.
See also operator!=().
No notes