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.

Added explicit where it was missing. 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.

Change-Id: I579e8714f94884dc555b673c9f85508f17cdc99d
Task-number: QTBUG-45291
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/datavisualization/data/qcustom3dvolume.h b/src/datavisualization/data/qcustom3dvolume.h
index 386a8045..966c01f2 100644
--- a/src/datavisualization/data/qcustom3dvolume.h
+++ b/src/datavisualization/data/qcustom3dvolume.h
@@ -54,12 +54,12 @@ class QT_DATAVISUALIZATION_EXPORT QCustom3DVolume : public QCustom3DItem
 
 public:
 
-    explicit QCustom3DVolume(QObject *parent = 0);
+    explicit QCustom3DVolume(QObject *parent = Q_NULLPTR);
     explicit QCustom3DVolume(const QVector3D &position, const QVector3D &scaling,
                              const QQuaternion &rotation, int textureWidth,
                              int textureHeight, int textureDepth,
                              QVector<uchar> *textureData, QImage::Format textureFormat,
-                             const QVector<QRgb> &colorTable, QObject *parent = 0);
+                             const QVector<QRgb> &colorTable, QObject *parent = Q_NULLPTR);
     virtual ~QCustom3DVolume();
 
     void setTextureWidth(int value);