QTextOStream and void*

[mclark]

I need to extract a void* from a QTextOStream.

QDataStream dataStream;
void* pData;
 
dataStream >> pData;

QDataStream dataStream;
void* pData;

dataStream >> pData;

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The QTextOStream documentation states that an operator, << (const void*), exists but no >> (void*) operator is listed. Using the << operator, I can get the void* into the stream but can't get it out. What must I do to get my void* out of the stream?

Thank you!

[jacek]

Well... you could read it into an integer and do reinterpret_cast, but are you sure that this pointer will be still valid?

PS. Note that QTextOStream is a part of Qt3 Support module.

[mclark]

The pointers will be valid, but I was unaware of the Qt3 support mode. I've also tried the integer casting but have not been able to make that work.

I'm trying to move info from a table row from one table to another via drag and drop. The code I'm working with copies all table elements using the QTestOStream. I've added the pointer as a data value to one of the table cells.

Is there another stream class that would be better suited for handling both text and data?

As an alternative I could store the dragged info and reclaim it on the drop. I would rather not disrupt the existing code to do this, which is why I am trying to add another << / >> to the existing stream.

[jacek]

I've also tried the integer casting but have not been able to make that work.

Something like this should work:

Q_ASSERT( sizeof( quint32 ) == sizeof( void * ) );
stream << reinterpret_cast< quint32 >( ptr );
...
quint32 v;
stream >> v;
ptr = reinterpret_cast< void * >( v );

Q_ASSERT( sizeof( quint32 ) == sizeof( void * ) );
stream << reinterpret_cast< quint32 >( ptr );
...
quint32 v;
stream >> v;
ptr = reinterpret_cast< void * >( v );

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(if you have 64-bit system, you should use quint64).

Is there another stream class that would be better suited for handling both text and data?

You can try QDataStream.

[mclark]

Thanks for the tips. It's now working using the casting you suggested.