Re: [boost] A question regarding serialization lib

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2007-12-30 12:39:21

>-----Original Message-----
>From: boost-bounces_at_[hidden] 
>[mailto:boost-bounces_at_[hidden]] On Behalf Of Robert Ramey
>Sent: 30 December 2007 16:53
>To: boost_at_[hidden]
>Subject: Re: [boost] A question regarding serialization lib

>I would expect that in your test text1.doc would be identical 
>to text2.doc.
>
>UNLESS you have have floats/double in your classes.  In 
>general, it cannot
>be guarenteed that there is a one-to-one correspondence 
>between floatiing
>point values as represented by binary in ram to text numbers 
>represented
>as decimal based text.  So in this case I would expect text1.doc to not
>be identical to text2.doc.

The chances of this a very small 1 in 3 values of a very narrow range- and only MS is known to have this problem as the link below
shows.

The following feedback item you submitted at Microsoft Connect has been updated:

Product/Technology - Visual Studio and .NET Framework
Feedback ID - 98770
Feedback Title - Decimal digit string input to double may be 1 bit wrong.

The following fields or values changed:

Field Status changed from [Resolved] to [Closed]

To view these changes, click the following link, or paste the link into your web browser:

http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=98770 (requires sign-in)

Amazingly (to me at least) this is a 'feature' and may not be fixed - despite it looking very much like a simple out-by-1 error.

Paul

---
Paul A Bristow
Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
[phone] & SMS, Mobile [phone] & SMS
pbristow_at_[hidden]
 
>Arunava Saha wrote:
>> Dear experts,
>>
>>  I am using boost serialization library to serialize a huge database
>> (has a lot of stl containers, shared pointers etc. ). I have 
>a general
>> question regarding serialization lib of boost. Suppose I have
>> serialized
>> a database in text format (say, text1.doc), cleared the existing
>> database, import the exported one back and re-export (say, 
>text2.doc).
>> Now, should I see any difference between text1.doc and text2.doc?
>> Actually I am seeing some difference. If I shouldn't, can someone
>> point
>> me to the common mistakes one can do for which it 
>differences can take place?
>>
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