[Development] JSON 64 bit int

Bo Thorsen bo at vikingsoft.eu
Wed Feb 11 14:04:59 CET 2015

Den 11-02-2015 kl. 13:27 skrev Giuseppe D'Angelo:
> On 11 February 2015 at 12:12, Bo Thorsen <bo at vikingsoft.eu> wrote:
>> It's so easy to say we just follow the standard. But I have two current
>> projects where my customers say they send me a 64 bit database ID in a JSON
>> value. Converting those through a double might work, but can you guarantee
>> this?
> No, because IEEE754 64-bit floating point numbers can't represent all
> 64 bit integers... the right solution, from a JSON point of view, is
> not sending a number but a string.

Exactly, that's why I wrote "might". You don't know if the number you 
get is correct or not.

But we can't get the string from {"i":1}. You get an empty string if you 
do toString on the i value.

And that's the problem. People have web APIs that return uint64 as a 
number and I need to get that number. ATM the only way is to read it 
from the full QByteArray. If the toString would never fail and give me 
the contents or I can get the bytes from it or add the extra type 
reading functions - all three would work. The current meagre API is 
pretty much the only way that doesn't.

Bo Thorsen,
Director, Viking Software.

Viking Software
Qt and C++ developers for hire

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