QDataStream and QDebug

[babu198649]

hi
please point the error in the following code

QDataStream stream;
stream<<(qint32)12345;
qint32 i;
stream>>i;
qDebug()<<i<<" i";

QDataStream stream;
stream<<(qint32)12345;
qint32 i;
stream>>i;
qDebug()<<i<<" i";

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the output is

0  i

0  i

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i expect the output to be 12345.

[marcel]

You have no QIODevice set.
You should see a warning in the debug output about this/: "QDataStream: No device".

The data stream must be created with a QIODevice either by passing it in the constructor or via setDevice.

[babu198649]

thanks marcel

but even after constructing a QDataStream that operates on QByteArray i am getting the same output

heres the code

QByteArray ar;
		QDataStream stream(&ar, QIODevice::ReadWrite);
		stream<<(qint32)12345;
		qint32 i;
		stream>>i;
		qDebug()<<i<<" i";

QByteArray ar;
		QDataStream stream(&ar, QIODevice::ReadWrite);
		stream<<(qint32)12345;
		qint32 i;
		stream>>i;
		qDebug()<<i<<" i";

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the output is

0  i

0  i

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[jpn]

It's a stream. Streams don't work like that. You will have to seek the underlying device to beginning, just like in this other thread of yours.

[babu198649]

thanks jpn

it worked after using this statement

stream.device()->seek(0);

stream.device()->seek(0);

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how to copy one QDataStream to another QDataStream.