Add explicit and make public headers compile with -Wzero-as-null-pointer-constant

... or equivalent.

QtBase 5.6 headers already compile that way, so let the other
modules follow suit.

Cleaned up placement of * and & in parameters as a drive-by.

Added explicit where it was missing as a drive-by. This is
not a source-incompatible change, because code that breaks
by this is a bug. Let's not have this sitting around in an LTS.

Task-number: QTBUG-45291
Change-Id: If81ed0c71393aee21d347f5ade4bf3fcc07cd82f
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

4 files changed, 5 insertions, 5 deletions

diff --git a/src/multimediawidgets/qcameraviewfinder.h b/src/multimediawidgets/qcameraviewfinder.h
index 65556c417..9bb2bda43 100644
--- a/src/multimediawidgets/qcameraviewfinder.h
+++ b/src/multimediawidgets/qcameraviewfinder.h
@@ -55,7 +55,7 @@ class Q_MULTIMEDIAWIDGETS_EXPORT QCameraViewfinder : public QVideoWidget
 {
     Q_OBJECT
 public:
-    QCameraViewfinder(QWidget *parent = 0);
+    explicit QCameraViewfinder(QWidget *parent = Q_NULLPTR);
     ~QCameraViewfinder();
 
     QMediaObject *mediaObject() const;
diff --git a/src/multimediawidgets/qgraphicsvideoitem.h b/src/multimediawidgets/qgraphicsvideoitem.h
index 76dbae2e0..e43de0157 100644
--- a/src/multimediawidgets/qgraphicsvideoitem.h
+++ b/src/multimediawidgets/qgraphicsvideoitem.h
@@ -57,7 +57,7 @@ class Q_MULTIMEDIAWIDGETS_EXPORT QGraphicsVideoItem : public QGraphicsObject, pu
     Q_PROPERTY(QSizeF size READ size WRITE setSize)
     Q_PROPERTY(QSizeF nativeSize READ nativeSize NOTIFY nativeSizeChanged)
 public:
-    QGraphicsVideoItem(QGraphicsItem *parent = 0);
+    explicit QGraphicsVideoItem(QGraphicsItem *parent = Q_NULLPTR);
     ~QGraphicsVideoItem();
 
     QMediaObject *mediaObject() const;
@@ -75,7 +75,7 @@ public:
 
     QRectF boundingRect() const;
 
-    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0);
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = Q_NULLPTR);
 
 Q_SIGNALS:
     void nativeSizeChanged(const QSizeF &size);
diff --git a/src/multimediawidgets/qvideowidget.h b/src/multimediawidgets/qvideowidget.h
index 2f5eade30..1e67de886 100644
--- a/src/multimediawidgets/qvideowidget.h
+++ b/src/multimediawidgets/qvideowidget.h
@@ -58,7 +58,7 @@ class Q_MULTIMEDIAWIDGETS_EXPORT QVideoWidget : public QWidget, public QMediaBin
     Q_PROPERTY(int saturation READ saturation WRITE setSaturation NOTIFY saturationChanged)
 
 public:
-    QVideoWidget(QWidget *parent = 0);
+    explicit QVideoWidget(QWidget *parent = Q_NULLPTR);
     ~QVideoWidget();
 
     QMediaObject *mediaObject() const;
diff --git a/src/multimediawidgets/qvideowidgetcontrol.h b/src/multimediawidgets/qvideowidgetcontrol.h
index c77d646db..dca9f2dd0 100644
--- a/src/multimediawidgets/qvideowidgetcontrol.h
+++ b/src/multimediawidgets/qvideowidgetcontrol.h
@@ -79,7 +79,7 @@ Q_SIGNALS:
     void saturationChanged(int saturation);
 
 protected:
-    QVideoWidgetControl(QObject *parent = 0);
+    explicit QVideoWidgetControl(QObject *parent = Q_NULLPTR);
 };
 
 #define QVideoWidgetControl_iid "org.qt-project.qt.videowidgetcontrol/5.0"