9 files changed, 16 insertions, 16 deletions
diff --git a/src/corelib/io/qbuffer.h b/src/corelib/io/qbuffer.h
index 1b2758d040..233c702213 100644
--- a/src/corelib/io/qbuffer.h
+++ b/src/corelib/io/qbuffer.h
@@ -51,8 +51,8 @@ class Q_CORE_EXPORT QBuffer : public QIODevice
 
 public:
 #ifndef QT_NO_QOBJECT
-     explicit QBuffer(QObject *parent = 0);
-     QBuffer(QByteArray *buf, QObject *parent = 0);
+     explicit QBuffer(QObject *parent = Q_NULLPTR);
+     QBuffer(QByteArray *buf, QObject *parent = Q_NULLPTR);
 #else
      QBuffer();
      explicit QBuffer(QByteArray *buf);
diff --git a/src/corelib/io/qfile.h b/src/corelib/io/qfile.h
index 35a73680af..4eac710d4c 100644
--- a/src/corelib/io/qfile.h
+++ b/src/corelib/io/qfile.h
@@ -134,7 +134,7 @@ protected:
 #ifdef QT_NO_QOBJECT
     QFile(QFilePrivate &dd);
 #else
-    QFile(QFilePrivate &dd, QObject *parent = 0);
+    QFile(QFilePrivate &dd, QObject *parent = Q_NULLPTR);
 #endif
 
 private:
diff --git a/src/corelib/io/qfiledevice.h b/src/corelib/io/qfiledevice.h
index e9320d8d31..afa42bd86b 100644
--- a/src/corelib/io/qfiledevice.h
+++ b/src/corelib/io/qfiledevice.h
@@ -119,7 +119,7 @@ protected:
     QFileDevice(QFileDevicePrivate &dd);
 #else
     explicit QFileDevice(QObject *parent);
-    QFileDevice(QFileDevicePrivate &dd, QObject *parent = 0);
+    QFileDevice(QFileDevicePrivate &dd, QObject *parent = Q_NULLPTR);
 #endif
 
     qint64 readData(char *data, qint64 maxlen) Q_DECL_OVERRIDE;
diff --git a/src/corelib/io/qfileselector.h b/src/corelib/io/qfileselector.h
index 967d5eee75..9ee3588780 100644
--- a/src/corelib/io/qfileselector.h
+++ b/src/corelib/io/qfileselector.h
@@ -44,7 +44,7 @@ class Q_CORE_EXPORT QFileSelector : public QObject
 {
     Q_OBJECT
 public:
-    explicit QFileSelector(QObject *parent = 0);
+    explicit QFileSelector(QObject *parent = Q_NULLPTR);
     ~QFileSelector();
 
     QString select(const QString &filePath) const;
diff --git a/src/corelib/io/qfilesystemwatcher.h b/src/corelib/io/qfilesystemwatcher.h
index 13d1782913..095b50d1e5 100644
--- a/src/corelib/io/qfilesystemwatcher.h
+++ b/src/corelib/io/qfilesystemwatcher.h
@@ -49,8 +49,8 @@ class Q_CORE_EXPORT QFileSystemWatcher : public QObject
     Q_DECLARE_PRIVATE(QFileSystemWatcher)
 
 public:
-    QFileSystemWatcher(QObject *parent = 0);
-    QFileSystemWatcher(const QStringList &paths, QObject *parent = 0);
+    QFileSystemWatcher(QObject *parent = Q_NULLPTR);
+    QFileSystemWatcher(const QStringList &paths, QObject *parent = Q_NULLPTR);
     ~QFileSystemWatcher();
 
     bool addPath(const QString &file);
diff --git a/src/corelib/io/qiodevice.h b/src/corelib/io/qiodevice.h
index 4f45805fca..b62c8d266c 100644
--- a/src/corelib/io/qiodevice.h
+++ b/src/corelib/io/qiodevice.h
@@ -140,7 +140,7 @@ protected:
 #ifdef QT_NO_QOBJECT
     QIODevice(QIODevicePrivate &dd);
 #else
-    QIODevice(QIODevicePrivate &dd, QObject *parent = 0);
+    QIODevice(QIODevicePrivate &dd, QObject *parent = Q_NULLPTR);
 #endif
     virtual qint64 readData(char *data, qint64 maxlen) = 0;
     virtual qint64 readLineData(char *data, qint64 maxlen);
diff --git a/src/corelib/io/qprocess.h b/src/corelib/io/qprocess.h
index df9fa886c1..81b3ac81d0 100644
--- a/src/corelib/io/qprocess.h
+++ b/src/corelib/io/qprocess.h
@@ -143,7 +143,7 @@ public:
     };
     Q_ENUM(ExitStatus)
 
-    explicit QProcess(QObject *parent = 0);
+    explicit QProcess(QObject *parent = Q_NULLPTR);
     virtual ~QProcess();
 
     void start(const QString &program, const QStringList &arguments, OpenMode mode = ReadWrite);
@@ -222,7 +222,7 @@ public:
 #if defined(Q_QDOC)
                               = QString()
 #endif
-                              , qint64 *pid = 0);
+                              , qint64 *pid = Q_NULLPTR);
 #if !defined(Q_QDOC)
     static bool startDetached(const QString &program, const QStringList &arguments); // ### Qt6: merge overloads
 #endif
diff --git a/src/corelib/io/qsavefile.h b/src/corelib/io/qsavefile.h
index 3f5f09bf5c..085378ed4e 100644
--- a/src/corelib/io/qsavefile.h
+++ b/src/corelib/io/qsavefile.h
@@ -58,7 +58,7 @@ class Q_CORE_EXPORT QSaveFile : public QFileDevice
 public:
 
     explicit QSaveFile(const QString &name);
-    explicit QSaveFile(QObject *parent = 0);
+    explicit QSaveFile(QObject *parent = Q_NULLPTR);
     explicit QSaveFile(const QString &name, QObject *parent);
     ~QSaveFile();
 
diff --git a/src/corelib/io/qsettings.h b/src/corelib/io/qsettings.h
index f7a7bdbb19..8f41273ffa 100644
--- a/src/corelib/io/qsettings.h
+++ b/src/corelib/io/qsettings.h
@@ -105,13 +105,13 @@ public:
 
 #ifndef QT_NO_QOBJECT
     explicit QSettings(const QString &organization,
-                       const QString &application = QString(), QObject *parent = 0);
+                       const QString &application = QString(), QObject *parent = Q_NULLPTR);
     QSettings(Scope scope, const QString &organization,
-              const QString &application = QString(), QObject *parent = 0);
+              const QString &application = QString(), QObject *parent = Q_NULLPTR);
     QSettings(Format format, Scope scope, const QString &organization,
-              const QString &application = QString(), QObject *parent = 0);
-    QSettings(const QString &fileName, Format format, QObject *parent = 0);
-    explicit QSettings(QObject *parent = 0);
+              const QString &application = QString(), QObject *parent = Q_NULLPTR);
+    QSettings(const QString &fileName, Format format, QObject *parent = Q_NULLPTR);
+    explicit QSettings(QObject *parent = Q_NULLPTR);
 #else
     explicit QSettings(const QString &organization,
                        const QString &application = QString());