Doc: replace 0 with \nullptr in documentation

Replace some more 0 with \nullptr.

Change-Id: I2af91bf3712eef5161b11da0c44614bc039ade03
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

src/corelib/codecs/qtextcodec.cpp

@@ -764,7 +764,7 @@ QList<QByteArray> QTextCodec::aliases() const
     encoding of the subclass to Unicode, and returns the result in a
     QString.
 
-    \a state can be 0, in which case the conversion is stateless and
+    \a state can be \nullptr, in which case the conversion is stateless and
     default conversion rules should be used. If state is not 0, the
     codec should save the state after the conversion in \a state, and
     adjust the \c remainingChars and \c invalidChars members of the struct.
@@ -780,7 +780,7 @@ QList<QByteArray> QTextCodec::aliases() const
     from Unicode to the encoding of the subclass, and returns the result
     in a QByteArray.
 
-    \a state can be 0 in which case the conversion is stateless and
+    \a state can be \nullptr in which case the conversion is stateless and
     default conversion rules should be used. If state is not 0, the
     codec should save the state after the conversion in \a state, and
     adjust the \c remainingChars and \c invalidChars members of the struct.

src/corelib/kernel/qobject.cpp

@@ -2934,8 +2934,8 @@ QMetaObject::Connection QObject::connect(const QObject *sender, const QMetaMetho
     0 may be used as a wildcard, meaning "any signal", "any receiving
     object", or "any slot in the receiving object", respectively.
 
-    The \a sender may never be 0. (You cannot disconnect signals from
-    more than one object in a single call.)
+    The \a sender may never be \nullptr. (You cannot disconnect signals
+    from more than one object in a single call.)
 
     If \a signal is 0, it disconnects \a receiver and \a method from
     any signal. If not, only the specified signal is disconnected.
@@ -2946,8 +2946,8 @@ QMetaObject::Connection QObject::connect(const QObject *sender, const QMetaMetho
 
     If \a method is 0, it disconnects anything that is connected to \a
     receiver. If not, only slots named \a method will be disconnected,
-    and all other slots are left alone. The \a method must be 0 if \a
-    receiver is left out, so you cannot disconnect a
+    and all other slots are left alone. The \a method must be \nullptr
+    if \a receiver is left out, so you cannot disconnect a
     specifically-named slot on all objects.
 
     \sa connect()
@@ -4991,8 +4991,8 @@ bool QObject::disconnect(const QMetaObject::Connection &connection)
     0 may be used as a wildcard, meaning "any signal", "any receiving
     object", or "any slot in the receiving object", respectively.
 
-    The \a sender may never be 0. (You cannot disconnect signals from
-    more than one object in a single call.)
+    The \a sender may never be \nullptr. (You cannot disconnect signals
+    from more than one object in a single call.)
 
     If \a signal is 0, it disconnects \a receiver and \a method from
     any signal. If not, only the specified signal is disconnected.
@@ -5003,8 +5003,8 @@ bool QObject::disconnect(const QMetaObject::Connection &connection)
 
     If \a method is 0, it disconnects anything that is connected to \a
     receiver. If not, only slots named \a method will be disconnected,
-    and all other slots are left alone. The \a method must be 0 if \a
-    receiver is left out, so you cannot disconnect a
+    and all other slots are left alone. The \a method must be \nullptr
+    if \a receiver is left out, so you cannot disconnect a
     specifically-named slot on all objects.
 
     \note It is not possible to use this overload to diconnect signals

src/corelib/plugin/qlibrary.cpp

@@ -133,8 +133,8 @@ QT_BEGIN_NAMESPACE
     The following code snippet loads a library, resolves the symbol
     "mysymbol", and calls the function if everything succeeded. If
     something goes wrong, e.g. the library file does not exist or the
-    symbol is not defined, the function pointer will be 0 and won't be
-    called.
+    symbol is not defined, the function pointer will be \nullptr and
+    won't be called.
 
     \snippet code/src_corelib_plugin_qlibrary.cpp 0
 

src/gui/itemmodels/qstandarditemmodel.cpp

@@ -1905,7 +1905,7 @@ QStandardItem *QStandardItem::takeChild(int row, int column)
 /*!
     Removes \a row without deleting the row items, and returns a list of
     pointers to the removed items. For items in the row that have not been
-    set, the corresponding pointers in the list will be 0.
+    set, the corresponding pointers in the list will be \nullptr.
 
     \sa removeRow(), insertRow(), takeColumn()
 */
@@ -1939,7 +1939,7 @@ QList<QStandardItem*> QStandardItem::takeRow(int row)
 /*!
     Removes \a column without deleting the column items, and returns a list of
     pointers to the removed items. For items in the column that have not been
-    set, the corresponding pointers in the list will be 0.
+    set, the corresponding pointers in the list will be \nullptr.
 
     \sa removeColumn(), insertColumn(), takeRow()
 */
@@ -2718,7 +2718,7 @@ QStandardItem *QStandardItemModel::takeItem(int row, int column)
     Removes the given \a row without deleting the row items, and returns a
     list of pointers to the removed items. The model releases ownership of the
     items. For items in the row that have not been set, the corresponding
-    pointers in the list will be 0.
+    pointers in the list will be \nullptr.
 
     \sa takeColumn()
 */
@@ -2734,7 +2734,7 @@ QList<QStandardItem*> QStandardItemModel::takeRow(int row)
     Removes the given \a column without deleting the column items, and returns
     a list of pointers to the removed items. The model releases ownership of
     the items. For items in the column that have not been set, the
-    corresponding pointers in the list will be 0.
+    corresponding pointers in the list will be \nullptr.
 
     \sa takeRow()
 */

src/gui/kernel/qplatformcursor.cpp

@@ -89,7 +89,7 @@ QT_BEGIN_NAMESPACE
     set or the system default cursor should take effect.
 
     \a window is a pointer to the window currently displayed at QCursor::pos(). Note
-    that this may be 0 if the current position is not occupied by a displayed widget.
+    that this may be \nullptr if the current position is not occupied by a displayed widget.
 
     \sa QCursor::pos()
 */

src/gui/kernel/qwindow.cpp

@@ -688,7 +688,8 @@ QWindow *QWindow::parent() const
     Sets the \a parent Window. This will lead to the windowing system managing
     the clip of the window, so it will be clipped to the \a parent window.
 
-    Setting \a parent to be 0 will make the window become a top level window.
+    Setting \a parent to be \nullptr will make the window become a top level
+    window.
 
     If \a parent is a window created by fromWinId(), then the current window
     will be embedded inside \a parent, if the platform supports it.

src/widgets/graphicsview/qgraphicsscene.cpp

@@ -5552,8 +5552,8 @@ bool QGraphicsScene::focusNextPrevChild(bool next)
     is a pointer to the item that gained input focus, or \nullptr if focus was lost.
     \a reason is the reason for the focus change (e.g., if the scene was
     deactivated while an input field had focus, \a oldFocusItem would point
-    to the input field item, \a newFocusItem would be 0, and \a reason would be
-    Qt::ActiveWindowFocusReason.
+    to the input field item, \a newFocusItem would be \nullptr, and \a reason
+    would be Qt::ActiveWindowFocusReason.
 */
 
 /*!

src/widgets/kernel/qtooltip.cpp

@@ -482,8 +482,8 @@ bool QTipLabel::tipChanged(const QPoint &pos, const QString &text, QObject *o)
 
     The \a rect is in the coordinates of the widget you specify with
     \a w. If the \a rect is not empty you must specify a widget.
-    Otherwise this argument can be 0 but it is used to determine the
-    appropriate screen on multi-head systems.
+    Otherwise this argument can be \nullptr but it is used to
+    determine the appropriate screen on multi-head systems.
 
     If \a text is empty the tool tip is hidden. If the text is the
     same as the currently shown tooltip, the tip will \e not move.

src/widgets/kernel/qwidget.cpp

@@ -1009,8 +1009,8 @@ struct QWidgetExceptionCleaner
     deleted.
 
     The widget flags argument, \a f, is normally 0, but it can be set
-    to customize the frame of a window (i.e. \a
-    parent must be 0). To customize the frame, use a value composed
+    to customize the frame of a window (i.e. \a parent must be
+    \nullptr). To customize the frame, use a value composed
     from the bitwise OR of any of the \l{Qt::WindowFlags}{window flags}.
 
     If you add a child widget to an already visible widget you must
@@ -4232,7 +4232,7 @@ void QWidget::setFixedHeight(int h)
 
 /*!
     Translates the widget coordinate \a pos to the coordinate system
-    of \a parent. The \a parent must not be 0 and must be a parent
+    of \a parent. The \a parent must not be \nullptr and must be a parent
     of the calling widget.
 
     \sa mapFrom(), mapToParent(), mapToGlobal(), underMouse()
@@ -4257,7 +4257,7 @@ QPoint QWidget::mapTo(const QWidget * parent, const QPoint & pos) const
 /*!
     Translates the widget coordinate \a pos from the coordinate system
     of \a parent to this widget's coordinate system. The \a parent
-    must not be 0 and must be a parent of the calling widget.
+    must not be \nullptr and must be a parent of the calling widget.
 
     \sa mapTo(), mapFromParent(), mapFromGlobal(), underMouse()
 */

src/widgets/widgets/qabstractspinbox.cpp

@@ -688,7 +688,7 @@ QLineEdit *QAbstractSpinBox::lineEdit() const
     \fn void QAbstractSpinBox::setLineEdit(QLineEdit *lineEdit)
 
     Sets the line edit of the spinbox to be \a lineEdit instead of the
-    current line edit widget. \a lineEdit cannot be 0.
+    current line edit widget. \a lineEdit cannot be \nullptr.
 
     QAbstractSpinBox takes ownership of the new lineEdit
 

src/widgets/widgets/qcombobox.cpp

@@ -2034,7 +2034,7 @@ QAbstractItemModel *QComboBox::model() const
 }
 
 /*!
-    Sets the model to be \a model. \a model must not be 0.
+    Sets the model to be \a model. \a model must not be \nullptr.
     If you want to clear the contents of a model, call clear().
 
     \sa clear()