[Qt-interest] unsigned char

[Shaun van Wyngaard (Home)]

Thanks. I will try it tomorrow.
Shaun

--------------------------------------------------
From: "Ian Thomson" <Ian.Thomson at iongeo.com>
Sent: Tuesday, November 03, 2009 7:17 PM
To: <qt-interest at trolltech.com>
Subject: Re: [Qt-interest] unsigned char

> Hi,
>
> Those are signed chars. If you use the data() function of QByteArray,
> you can cast it to unsigned char like this:
>
> unsigned char* ublock = static_cast<unsigned char*>(block->data());
> qDebug() << QString::number(ublock[11], 16);
>
> I believe that should work.
>
> Cheers,
> Ian.
>
> Shaun van Wyngaard (Home) wrote:
>> I have recently had the "misfortune" to encounter unsigned char usage,
>> and need some help on it. If this is indeed what it is.
>> Specifically, I am reading some values from QTcpSocket into a QByteArray
>> by means of the following code.
>>
>> QByteArray block;
>> block = tcpSocket->readAll();
>>
>> where tcpSocket is of type QTcpSocket.
>> Now when I do a debug run using watchpoints, the values within block are
>> as expected, specifically I am looking at the following indices, with
>> the associated values as shown in the local variables being monitored.
>>
>> block[9] : 3d
>> block[10] : 7f
>> block[11] : bf
>> block[12] : 26
>>
>> However, when I try print them using
>>
>> qDebug() << QString
>> <http://doc.trolltech.com/latest/QString.html>::number(block[9],16);
>> qDebug() << QString
>> <http://doc.trolltech.com/latest/QString.html>::number(block[10],16);
>> qDebug() << QString
>> <http://doc.trolltech.com/latest/QString.html>::number(block[11],16);
>> qDebug() << QString
>> <http://doc.trolltech.com/latest/QString.html>::number(block[12],16);
>>
>>  I get the following output:
>>
>> "3d"
>> "7e"
>> "ffffffffffffffbf"
>> "26"
>>
>> A workaround to this is to check if the value is less than zero, and if
>> yes, then to add 255 (if I remember what I saw earlier), and that will
>> revert it back to its original value, in this case the third value being
>> the one needing attention. This I found after searching for awhile. Now
>> I have an idea that QByteArray should be able to handle this situation
>> automatically, I just can't seem to figure out the code. Could someone
>> help me please?
>>
>> Thanks,
>> Shaun
>>
>>
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>>
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