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>

3 files changed, 3 insertions, 3 deletions

diff --git a/src/multimedia/video/qabstractvideofilter.h b/src/multimedia/video/qabstractvideofilter.h
index 77f035e0a..51b6ee7b4 100644
--- a/src/multimedia/video/qabstractvideofilter.h
+++ b/src/multimedia/video/qabstractvideofilter.h
@@ -62,7 +62,7 @@ class Q_MULTIMEDIA_EXPORT QAbstractVideoFilter : public QObject
     Q_PROPERTY(bool active READ isActive WRITE setActive NOTIFY activeChanged)
 
 public:
-    explicit QAbstractVideoFilter(QObject *parent = 0);
+    explicit QAbstractVideoFilter(QObject *parent = Q_NULLPTR);
     ~QAbstractVideoFilter();
 
     bool isActive() const;
diff --git a/src/multimedia/video/qabstractvideosurface.h b/src/multimedia/video/qabstractvideosurface.h
index f8aefc3ba..e2b684125 100644
--- a/src/multimedia/video/qabstractvideosurface.h
+++ b/src/multimedia/video/qabstractvideosurface.h
@@ -58,7 +58,7 @@ public:
         ResourceError
     };
 
-    explicit QAbstractVideoSurface(QObject *parent = 0);
+    explicit QAbstractVideoSurface(QObject *parent = Q_NULLPTR);
     ~QAbstractVideoSurface();
 
     virtual QList<QVideoFrame::PixelFormat> supportedPixelFormats(
diff --git a/src/multimedia/video/qvideoprobe.h b/src/multimedia/video/qvideoprobe.h
index 5de594f06..d3c8dbfda 100644
--- a/src/multimedia/video/qvideoprobe.h
+++ b/src/multimedia/video/qvideoprobe.h
@@ -47,7 +47,7 @@ class Q_MULTIMEDIA_EXPORT QVideoProbe : public QObject
 {
     Q_OBJECT
 public:
-    explicit QVideoProbe(QObject *parent = 0);
+    explicit QVideoProbe(QObject *parent = Q_NULLPTR);
     ~QVideoProbe();
 
     bool setSource(QMediaObject *source);