On 9/3/2014 6:11 PM, Rogers Nate wrote:
> On 09/03/2014 11:53 AM, Calogero Mauceri wrote:
>> Hi all,
>>
>> I'm doing something really simple, but which is driving me crazy.
>>
>> I'm reading a string from a file and converting it to a long long
>> integer, but the conversion fails.
>> The code I'm running is as simple as this
>>
>> // this string is read from a file
>> QString str("18446744073709551615");
>> bool ok;
>> qint64 value = str.toLongLong(&ok); // Error
>>
>> the number should be representable in 64 bit. Am I doing something wrong?
>>
>> More hints, if I convert the number to unsigned long long integer then
>> it works
>>
>> bool ok;
>> quint64 value = str.toULongLong(&ok); // OK
>>
>> Similarly initializing the long long from the literal value is failing too
>>
>> Q_INT64_C(18446744073709551615) ; // Error, returns -1
>> Q_UINT64_C(18446744073709551615); // OK
>>
>> Thanks for your help!
>> Calogero
>>
> 18446744073709551615 is too big to fit into a long long. It is actually the
> biggest number you can have a unsigned long long. A long long can't fit the
> same size number because it has to use one bit to hold the sign. The maximum
> number you can fit in a long long is 9223372036854775807.
>
Nate,
thanks for your reply, now I see the problem.
Calogero
--
Calogero Mauceri
Software Engineer
Applied Coherent Technology Corporation (ACT)
www.actgate.com
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