Clear unused members of the overlapped structure before each usage

For more detail, see remarks from the MSDN:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms684342%28v=vs.85%29.aspx

Change-Id: Id6e5adc48e8a4648f1aabba598696b34c658a159
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/serialport/qserialport_win.cpp b/src/serialport/qserialport_win.cpp
index f8873dda..eef3d2b6 100644
--- a/src/serialport/qserialport_win.cpp
+++ b/src/serialport/qserialport_win.cpp
@@ -88,6 +88,14 @@ QT_BEGIN_NAMESPACE
 
 #ifndef Q_OS_WINCE
 
+static void initializeOverlappedStructure(OVERLAPPED &overlapped)
+{
+    overlapped.Internal = 0;
+    overlapped.InternalHigh = 0;
+    overlapped.Offset = 0;
+    overlapped.OffsetHigh = 0;
+}
+
 class AbstractOverlappedEventNotifier : public QWinEventNotifier
 {
     Q_OBJECT
@@ -144,6 +152,7 @@ public:
     }
 
     void startWaitCommEvent() {
+        initializeOverlappedStructure(o);
         if (!::WaitCommEvent(dptr->descriptor, &triggeredEventMask, &o)) {
             const QSerialPort::SerialPortError error = dptr->decodeSystemError();
             if (error != QSerialPort::NoError) {
@@ -671,6 +680,7 @@ bool QSerialPortPrivate::startAsyncRead()
         return false;
     }
 
+    initializeOverlappedStructure(*n->overlappedPointer());
     if (::ReadFile(descriptor, readChunkBuffer.data(), bytesToRead, NULL, n->overlappedPointer()))
         return true;
 
@@ -710,6 +720,7 @@ bool QSerialPortPrivate::startAsyncWrite(int maxSize)
 
     n->setEnabled(true);
 
+    initializeOverlappedStructure(*n->overlappedPointer());
     if (::WriteFile(descriptor, ptr, nextSize, NULL, n->overlappedPointer()))
         return true;