1 files changed, 12 insertions, 6 deletions
diff --git a/src/corelib/xml/qxmlstream.cpp b/src/corelib/xml/qxmlstream.cpp
index 8e62804025..3949d2c3ac 100644
--- a/src/corelib/xml/qxmlstream.cpp
+++ b/src/corelib/xml/qxmlstream.cpp
@@ -3025,10 +3025,14 @@ void QXmlStreamWriterPrivate::checkIfASCIICompatibleCodec()
 {
 #ifndef QT_NO_TEXTCODEC
     Q_ASSERT(encoder);
-    // assumes ASCII-compatibility for all 8-bit encodings
-    QChar space = QLatin1Char(' ');
-    const QByteArray bytes = encoder->fromUnicode(&space, 1);
-    isCodecASCIICompatible = (bytes.count() == 1);
+    // test ASCII-compatibility using the letter 'a'
+    QChar letterA = QLatin1Char('a');
+    const QByteArray bytesA = encoder->fromUnicode(&letterA, 1);
+    const bool isCodecASCIICompatibleA = (bytesA.count() == 1) && (bytesA[0] == 0x61) ;
+    QChar letterLess = QLatin1Char('<');
+    const QByteArray bytesLess = encoder->fromUnicode(&letterLess, 1);
+    const bool isCodecASCIICompatibleLess = (bytesLess.count() == 1) && (bytesLess[0] == 0x3C) ;
+    isCodecASCIICompatible = isCodecASCIICompatibleA && isCodecASCIICompatibleLess ;
 #else
     isCodecASCIICompatible = true;
 #endif
@@ -3790,7 +3794,8 @@ void QXmlStreamWriter::writeStartDocument(const QString &version)
 #ifdef QT_NO_TEXTCODEC
         d->write("iso-8859-1");
 #else
-        d->write(d->codec->name().constData(), d->codec->name().length());
+        const QByteArray name = d->codec->name();
+        d->write(name.constData(), name.length());
 #endif
     }
     d->write("\"?>");
@@ -3813,7 +3818,8 @@ void QXmlStreamWriter::writeStartDocument(const QString &version, bool standalon
 #ifdef QT_NO_TEXTCODEC
         d->write("iso-8859-1");
 #else
-        d->write(d->codec->name().constData(), d->codec->name().length());
+        const QByteArray name = d->codec->name();
+        d->write(name.constData(), name.length());
 #endif
     }
     if (standalone)