3 files changed, 12 insertions, 10 deletions
diff --git a/src/serialport/qserialport.h b/src/serialport/qserialport.h
index d0f65b5e..8a0bbb11 100644
--- a/src/serialport/qserialport.h
+++ b/src/serialport/qserialport.h
@@ -287,6 +287,7 @@ private:
     Q_PRIVATE_SLOT(d_func(), bool _q_completeAsyncCommunication())
     Q_PRIVATE_SLOT(d_func(), bool _q_completeAsyncRead())
     Q_PRIVATE_SLOT(d_func(), bool _q_completeAsyncWrite())
+    Q_PRIVATE_SLOT(d_func(), bool _q_startAsyncWrite())
 #endif
 };
 
diff --git a/src/serialport/qserialport_win.cpp b/src/serialport/qserialport_win.cpp
index ecbf464a..18cef1ea 100644
--- a/src/serialport/qserialport_win.cpp
+++ b/src/serialport/qserialport_win.cpp
@@ -259,7 +259,7 @@ bool QSerialPortPrivate::setRequestToSend(bool set)
 
 bool QSerialPortPrivate::flush()
 {
-    return startAsyncWrite();
+    return _q_startAsyncWrite();
 }
 
 bool QSerialPortPrivate::clear(QSerialPort::Directions directions)
@@ -313,7 +313,7 @@ void QSerialPortPrivate::startWriting()
     if (!writeStarted) {
         if (!startAsyncWriteTimer) {
             startAsyncWriteTimer = new QTimer(q);
-            q->connect(startAsyncWriteTimer, SIGNAL(timeout()), q, SLOT(_q_completeAsyncWrite()));
+            q->connect(startAsyncWriteTimer, SIGNAL(timeout()), q, SLOT(_q_startAsyncWrite()));
             startAsyncWriteTimer->setSingleShot(true);
         }
         startAsyncWriteTimer->start(0);
@@ -327,7 +327,7 @@ bool QSerialPortPrivate::waitForReadyRead(int msecs)
     QElapsedTimer stopWatch;
     stopWatch.start();
 
-    if (!writeStarted && !startAsyncWrite())
+    if (!writeStarted && !_q_startAsyncWrite())
         return false;
 
     const qint64 initialReadBufferSize = readBuffer.size();
@@ -381,7 +381,7 @@ bool QSerialPortPrivate::waitForBytesWritten(int msecs)
     QElapsedTimer stopWatch;
     stopWatch.start();
 
-    if (!writeStarted && !startAsyncWrite())
+    if (!writeStarted && !_q_startAsyncWrite())
         return false;
 
     forever {
@@ -543,17 +543,18 @@ bool QSerialPortPrivate::_q_completeAsyncWrite()
     Q_Q(QSerialPort);
 
     if (writeStarted) {
-        writeStarted = false;
         const qint64 bytesTransferred = handleOverlappedResult(QSerialPort::Output, writeCompletionOverlapped);
-        if (bytesTransferred == qint64(-1))
+        if (bytesTransferred == qint64(-1)) {
+            writeStarted = false;
             return false;
-        if (bytesTransferred > 0) {
+        } else if (bytesTransferred > 0) {
             writeBuffer.free(bytesTransferred);
             emit q->bytesWritten(bytesTransferred);
         }
+        writeStarted = false;
     }
 
-    return startAsyncWrite();
+    return _q_startAsyncWrite();
 }
 
 bool QSerialPortPrivate::startAsyncCommunication()
@@ -605,7 +606,7 @@ bool QSerialPortPrivate::startAsyncRead()
     return true;
 }
 
-bool QSerialPortPrivate::startAsyncWrite()
+bool QSerialPortPrivate::_q_startAsyncWrite()
 {
     Q_Q(QSerialPort);
 
diff --git a/src/serialport/qserialport_win_p.h b/src/serialport/qserialport_win_p.h
index f4297ef5..cf30c189 100644
--- a/src/serialport/qserialport_win_p.h
+++ b/src/serialport/qserialport_win_p.h
@@ -108,7 +108,7 @@ public:
 
     bool startAsyncCommunication();
     bool startAsyncRead();
-    bool startAsyncWrite();
+    bool _q_startAsyncWrite();
 
     bool emulateErrorPolicy();
     void emitReadyRead();