[Interest] QDateTime + QXmlStreamWriter on non-UTF8 compatible systems

[Thiago Macieira]

On sexta-feira, 22 de dezembro de 2017 17:21:24 -02 Scott Bloom wrote:
> I was able to track down the issue.
> 
> Typically, I was writing to a QString, for some reason, there is an
> undocumented difference in the writer for QString vs QIODevice writing.

It's not really undocumented. QString is UTF-16, so it requires no encoding. 
QIODevice is 8-bit, so it encodes.

> From QXmlStreamWriter::writeStartDocument
> 
>     if (d->device) { // stringDevice does not get any encoding
>         d->write("\" encoding=\"");
> #ifdef QT_NO_TEXTCODEC
>         d->write("iso-8859-1");
> #else
>         d->write(d->codec->name().constData(), d->codec->name().length());
> #endif
>     }
> 
> The codec was not getting written out since I was using a QString, by
> changing to a QBuffer, the encoding is written out, and the XML can be read
> in properly.

Again, as expected.

> Note, according to the documentation there is NO differentiation of "String
> based" vs "Non String based" void QXmlStreamWriter::writeStartDocument()
> This is an overloaded function.

Right. 

> Frankly, I am not sure why this difference exists, but it should definitely
> be documented.

There's no need for it. Your bug isn't here yet.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center