[Development] Weird offseting in QDataStream

Christian Ehrlicher Ch.Ehrlicher at gmx.de
Fri Nov 8 10:29:38 CET 2013

Am 08.11.2013 10:15, schrieb Yves Bailly:
> Le 08/11/2013 10:05, Giuseppe D'Angelo a écrit :
>> On 8 November 2013 10:01, Yves Bailly <yves.bailly at sescoi.fr> wrote:
>>> As a float is 4 bytes, I would expect the second f.pos() to display "4"... but
>>> it displays "8", as if QDataStream had moved 8 bytes ahead instead of just 4.
>>> Needless to say, the read float is wrong...
>>> Am I missing something here, or is it a bug?
>> See QDataStream::setFloatingPointPrecision. The default is double.
> That's pretty strange... what if I want to read a float then a double? do I
> have to switch between the two each time?
> Does this means it's impossible to use code like this:
> float f;
> double d;
> datastream >> f >> d;
> ?
setFloatingPointPrecision does only change the way the floating point 
numbers are stored in the data stream, not what you read from it.
Also I think you're wrong in what you want to do. You can't read data 
from a file which was not stored with QDataStream before! See 


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