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211 lines
7.0 KiB
211 lines
7.0 KiB
13 years ago
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'\" t
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.TH QPtrListIterator 3qt "2 February 2007" "Trolltech AS" \" -*- nroff -*-
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.\" Copyright 1992-2007 Trolltech ASA. All rights reserved. See the
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.\" license file included in the distribution for a complete license
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.\" statement.
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.\"
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.ad l
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.nh
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.SH NAME
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QPtrListIterator \- Iterator for QPtrList collections
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.SH SYNOPSIS
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13 years ago
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\fC#include <ntqptrlist.h>\fR
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13 years ago
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.PP
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Inherited by QObjectListIterator and QStrListIterator.
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.PP
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.SS "Public Members"
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.in +1c
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.ti -1c
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.BI "\fBQPtrListIterator\fR ( const QPtrList<type> & list )"
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.br
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.ti -1c
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.BI "\fB~QPtrListIterator\fR ()"
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.br
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.ti -1c
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.BI "uint \fBcount\fR () const"
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.br
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.ti -1c
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.BI "bool \fBisEmpty\fR () const"
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.br
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.ti -1c
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.BI "bool \fBatFirst\fR () const"
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.br
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.ti -1c
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.BI "bool \fBatLast\fR () const"
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.br
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.ti -1c
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.BI "type * \fBtoFirst\fR ()"
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.br
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.ti -1c
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.BI "type * \fBtoLast\fR ()"
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.br
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.ti -1c
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.BI "\fBoperator type *\fR () const"
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.br
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.ti -1c
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.BI "type * \fBoperator*\fR ()"
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.br
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.ti -1c
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.BI "type * \fBcurrent\fR () const"
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.br
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.ti -1c
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.BI "type * \fBoperator()\fR ()"
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.br
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.ti -1c
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.BI "type * \fBoperator++\fR ()"
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.br
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.ti -1c
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.BI "type * \fBoperator+=\fR ( uint jump )"
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.br
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.ti -1c
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.BI "type * \fBoperator--\fR ()"
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.br
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.ti -1c
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.BI "type * \fBoperator-=\fR ( uint jump )"
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.br
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.ti -1c
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.BI "QPtrListIterator<type> & \fBoperator=\fR ( const QPtrListIterator<type> & it )"
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.br
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.in -1c
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.SH DESCRIPTION
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The QPtrListIterator class provides an iterator for QPtrList collections.
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.PP
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Define a template instance QPtrListIterator<X> to create a list iterator that operates on QPtrList<X> (list of X*).
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.PP
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The following example is similar to the example in the QPtrList class documentation, but it uses QPtrListIterator. The class Employee is defined there.
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.PP
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.nf
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.br
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QPtrList<Employee> list;
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.br
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.br
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list.append( new Employee("John", "Doe", 50000) );
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.br
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list.append( new Employee("Jane", "Williams", 80000) );
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.br
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list.append( new Employee("Tom", "Jones", 60000) );
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.br
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.br
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QPtrListIterator<Employee> it( list );
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.br
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Employee *employee;
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.br
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while ( (employee = it.current()) != 0 ) {
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.br
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++it;
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.br
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cout << employee->surname().latin1() << ", " <<
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.br
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employee->forename().latin1() << " earns " <<
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.br
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employee->salary() << endl;
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.br
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}
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.br
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.fi
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.PP
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The output is
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.PP
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.nf
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.br
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Doe, John earns 50000
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.br
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Williams, Jane earns 80000
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.br
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Jones, Tom earns 60000
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.br
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.fi
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.PP
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Using a list iterator is a more robust way of traversing the list than using the QPtrList member functions first(), next(), current(), etc., as many iterators can traverse the same list independently.
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.PP
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An iterator has its own current list item and can get the next and previous list items. It doesn't modify the list in any way.
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.PP
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When an item is removed from the list, all iterators that point to that item are updated to point to QPtrList::current() instead to avoid dangling references.
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.PP
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See also QPtrList, Collection Classes, and Non-GUI Classes.
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.SH MEMBER FUNCTION DOCUMENTATION
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.SH "QPtrListIterator::QPtrListIterator ( const QPtrList<type> & list )"
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Constructs an iterator for \fIlist\fR. The current iterator item is set to point on the first item in the \fIlist\fR.
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.SH "QPtrListIterator::~QPtrListIterator ()"
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Destroys the iterator.
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.SH "bool QPtrListIterator::atFirst () const"
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Returns TRUE if the current iterator item is the first list item; otherwise returns FALSE.
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.PP
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See also toFirst() and atLast().
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.SH "bool QPtrListIterator::atLast () const"
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Returns TRUE if the current iterator item is the last list item; otherwise returns FALSE.
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.PP
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See also toLast() and atFirst().
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.SH "uint QPtrListIterator::count () const"
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Returns the number of items in the list this iterator operates on.
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.PP
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See also isEmpty().
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.PP
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Example: customlayout/card.cpp.
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.SH "type * QPtrListIterator::current () const"
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Returns a pointer to the current iterator item. If the iterator is positioned before the first item in the list or after the last item in the list, 0 is returned.
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.PP
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Examples:
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.)l canvas/canvas.cpp, customlayout/card.cpp, and customlayout/flow.cpp.
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.SH "bool QPtrListIterator::isEmpty () const"
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Returns TRUE if the list is empty; otherwise returns FALSE.
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.PP
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See also count().
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.SH "QPtrListIterator::operator type * () const"
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Cast operator. Returns a pointer to the current iterator item. Same as current().
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.SH "type * QPtrListIterator::operator() ()"
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Makes the succeeding item current and returns the original current item.
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.PP
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If the current iterator item was the last item in the list or if it was 0, 0 is returned.
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.SH "type * QPtrListIterator::operator* ()"
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Asterisk operator. Returns a pointer to the current iterator item. Same as current().
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.SH "type * QPtrListIterator::operator++ ()"
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Prefix ++ makes the succeeding item current and returns the new current item.
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.PP
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If the current iterator item was the last item in the list or if it was 0, 0 is returned.
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.SH "type * QPtrListIterator::operator+= ( uint jump )"
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Sets the current item to the item \fIjump\fR positions after the current item and returns a pointer to that item.
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.PP
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If that item is beyond the last item or if the list is empty, it sets the current item to 0 and returns 0
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.SH "type * QPtrListIterator::operator-- ()"
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Prefix - makes the preceding item current and returns the new current item.
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.PP
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If the current iterator item was the first item in the list or if it was 0, 0 is returned.
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.SH "type * QPtrListIterator::operator-= ( uint jump )"
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Returns the item \fIjump\fR positions before the current item or 0 if it is beyond the first item. Makes this the current item.
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.SH "QPtrListIterator<type> & QPtrListIterator::operator= ( const QPtrListIterator<type> & it )"
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Assignment. Makes a copy of the iterator \fIit\fR and returns a reference to this iterator.
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.SH "type * QPtrListIterator::toFirst ()"
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Sets the current iterator item to point to the first list item and returns a pointer to the item. Sets the current item to 0 and returns 0 if the list is empty.
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.PP
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See also toLast() and atFirst().
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.SH "type * QPtrListIterator::toLast ()"
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Sets the current iterator item to point to the last list item and returns a pointer to the item. Sets the current item to 0 and returns 0 if the list is empty.
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.PP
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See also toFirst() and atLast().
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.SH "SEE ALSO"
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.BR http://doc.trolltech.com/qptrlistiterator.html
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.BR http://www.trolltech.com/faq/tech.html
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.SH COPYRIGHT
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Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
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license file included in the distribution for a complete license
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statement.
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.SH AUTHOR
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Generated automatically from the source code.
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.SH BUGS
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If you find a bug in Qt, please report it as described in
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.BR http://doc.trolltech.com/bughowto.html .
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Good bug reports help us to help you. Thank you.
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.P
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The definitive Qt documentation is provided in HTML format; it is
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located at $QTDIR/doc/html and can be read using Qt Assistant or with
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a web browser. This man page is provided as a convenience for those
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users who prefer man pages, although this format is not officially
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supported by Trolltech.
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.P
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If you find errors in this manual page, please report them to
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.BR qt-bugs@trolltech.com .
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11 years ago
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Please include the name of the manual page (tqptrlistiterator.3qt) and the Qt
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13 years ago
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version (3.3.8).
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