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, 3 insertions, 3 deletions

diff --git a/src/datavisualization/theme/q3dtheme.h b/src/datavisualization/theme/q3dtheme.h
index 63ed0c47..236320bf 100644
--- a/src/datavisualization/theme/q3dtheme.h
+++ b/src/datavisualization/theme/q3dtheme.h
@@ -80,8 +80,8 @@ public:
     };
 
 public:
-    explicit Q3DTheme(QObject *parent = 0);
-    explicit Q3DTheme(Theme themeType, QObject *parent = 0);
+    explicit Q3DTheme(QObject *parent = Q_NULLPTR);
+    explicit Q3DTheme(Theme themeType, QObject *parent = Q_NULLPTR);
     virtual ~Q3DTheme();
 
     void setType(Theme themeType);
@@ -175,7 +175,7 @@ Q_SIGNALS:
     void colorStyleChanged(Q3DTheme::ColorStyle style);
 
 protected:
-    explicit Q3DTheme(Q3DThemePrivate *d, Theme themeType, QObject *parent = 0);
+    explicit Q3DTheme(Q3DThemePrivate *d, Theme themeType, QObject *parent = Q_NULLPTR);
 
     QScopedPointer<Q3DThemePrivate> d_ptr;