diff --git a/src/corelib/serialization/qdatastream.cpp b/src/corelib/serialization/qdatastream.cpp
index f1f45895aa..f1572b46c7 100644
--- a/src/corelib/serialization/qdatastream.cpp
+++ b/src/corelib/serialization/qdatastream.cpp
@@ -271,12 +271,6 @@ constexpr quint32 QDataStream::ExtendedSize;
 
 QDataStream::QDataStream()
 {
-    dev = nullptr;
-    owndev = false;
-    byteorder = BigEndian;
-    ver = Qt_DefaultCompiledVersion;
-    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
-    q_status = Ok;
 }
 
 /*!
@@ -288,11 +282,6 @@ QDataStream::QDataStream()
 QDataStream::QDataStream(QIODevice *d)
 {
     dev = d;                                // set device
-    owndev = false;
-    byteorder = BigEndian;                        // default byte order
-    ver = Qt_DefaultCompiledVersion;
-    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
-    q_status = Ok;
 }
 
 /*!
@@ -317,10 +306,6 @@ QDataStream::QDataStream(QByteArray *a, OpenMode flags)
     buf->open(flags);
     dev = buf;
     owndev = true;
-    byteorder = BigEndian;
-    ver = Qt_DefaultCompiledVersion;
-    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
-    q_status = Ok;
 }
 
 /*!
@@ -341,10 +326,6 @@ QDataStream::QDataStream(const QByteArray &a)
     buf->open(QIODevice::ReadOnly);
     dev = buf;
     owndev = true;
-    byteorder = BigEndian;
-    ver = Qt_DefaultCompiledVersion;
-    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
-    q_status = Ok;
 }
 
 /*!
diff --git a/src/corelib/serialization/qdatastream.h b/src/corelib/serialization/qdatastream.h
index 27694aacc3..e7ef94a8a7 100644
--- a/src/corelib/serialization/qdatastream.h
+++ b/src/corelib/serialization/qdatastream.h
@@ -216,13 +216,13 @@ private:
 
     QScopedPointer<QDataStreamPrivate> d;
 
-    QIODevice *dev;
-    bool owndev;
-    bool noswap;
+    QIODevice *dev = nullptr;
+    bool owndev = false;
+    bool noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
     quint8 fpPrecision = QDataStream::DoublePrecision;
-    quint8 q_status;
-    ByteOrder byteorder;
-    int ver;
+    quint8 q_status = Ok;
+    ByteOrder byteorder = BigEndian;
+    int ver = Qt_DefaultCompiledVersion;
     quint16 transactionDepth = 0;
 
 #if QT_CORE_REMOVED_SINCE(6, 7)