QPair(3qt)QPair(3qt)NAMEQPair - Value-based template class that provides a pair of elements
SYNOPSIS
#include <qpair.h>
Public Members
typedef T1 first_type
typedef T2 second_type
QPair ()
QPair ( const T1 & t1, const T2 & t2 )
QPair<T1, T2> & operator= ( const QPair<T1, T2> & other )
RELATED FUNCTION DOCUMENTATIONQPair qMakePair ( T1 t1, T2 t2 )
DESCRIPTION
The QPair class is a value-based template class that provides a pair of
elements.
QPair is a Qt implementation of an STL-like pair. It can be used in
your application if the standard pair<> is not available on your target
platforms.
QPair<T1, T2> defines a template instance to create a pair of values
that contains two values of type T1 and T2. Please note that QPair does
not store pointers to the two elements; it holds a copy of every
member. This is why these kinds of classes are called value based. If
you're interested in pointer based classes see, for example, QPtrList
and QDict.
QPair holds one copy of type T1 and one copy of type T2, but does not
provide iterators to access these elements. Instead, the two elements
(first and second) are public member variables of the pair. QPair owns
the contained elements. For more relaxed ownership semantics, see
QPtrCollection and friends which are pointer-based containers.
Some classes cannot be used within a QPair: for example, all classes
derived from QObject and thus all classes that implement widgets. Only
"values" can be used in a QPair. To qualify as a value the class must
provide:
A copy constructor
An assignment operator
A constructor that takes no arguments
Note that C++ defaults to field-by-field assignment operators and copy
constructors if no explicit version is supplied. In many cases this is
sufficient.
QPair uses an STL-like syntax to manipulate and address the objects it
contains. See the QTL documentation for more information.
Functions that need to return two values can use a QPair.
See also Qt Template Library Classes, Implicitly and Explicitly Shared
Classes, and Non-GUI Classes.
Member Type Documentation
QPair::first_type
The type of the first element in the pair.
QPair::second_type
The type of the second element in the pair.
MEMBER FUNCTION DOCUMENTATIONQPair::QPair ()
Constructs an empty pair. The first and second elements are default
constructed.
QPair::QPair ( const T1 & t1, const T2 & t2 )
Constructs a pair and initializes the first element with t1 and the
second element with t2.
RELATED FUNCTION DOCUMENTATIONQPair qMakePair ( T1 t1, T2 t2 )
This is a template convenience function. It is used to create a QPair<>
object that contains t1 and t2.
SEE ALSO
http://doc.trolltech.com/qpair.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports help us to
help you. Thank you.
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with a
web browser. This man page is provided as a convenience for those users
who prefer man pages, although this format is not officially supported
by Trolltech.
If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qpair.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QPair(3qt)