[Interest] Strange problem in template class (Iterator as value type of a QHash)

[Constantin Makshin]

g++ isn't bad at all, but sometimes its error messages may be quite
confusing/cryptic.
On Aug 23, 2013 8:39 PM, "Mandeep Sandhu" <mandeepsandhu.chd at gmail.com>
wrote:

>
>> Error from Clang:
>>
>>  error: template argument for template type parameter must be a type; did
>> you forget 'typename'?
>>
>
> It' right, in that I need to use typename 'somewhere', I just didn't know
> where (and why).
>
> I finally fixed it doing a typedef of this dependent type, which also
> makes it easy to type! :)
>
>
> template <typename K, typename V>
> class TemplateTest
> {
>     typedef typename QLinkedList<V>::iterator iter;
>
> public:
>     TemplateTest()
>     {
>         QHash<K, iter > h;
>         Q_UNUSED(h);
>     }
> ...
>
> There's a nice explanation about 'typename' keyword here:
> http://pages.cs.wisc.edu/~driscoll/typename.html
>
>
>> Note: use proper compiler next time.
>>
>
> Note:  Using g++, which is a _very_ proper compiler. It even has a
> "-pedantic" switch! ;)
>
> $ g++ --version
> g++ (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
>
> Regards,
> -mandeep
>
>
>>
>> > Error:
>> >
>> > templatetest.h:13: error: type/value mismatch at argument 2 in template
>> parameter list for 'template<class Key, class T> class QHash'
>> > templatetest.h:13: error:   expected a type, got
>> 'QLinkedList<V>::iterator'
>> > templatetest.h:13: error: invalid type in declaration before ';' token
>> >
>> > However, if I keep the value as a QList (remove iterator) it compile
>> fine.
>> >
>> > Whats the problem with storing a Iterator as the value?
>> >
>> > Thanks,
>> > -mandeep
>> >
>> > ,
>> > _______________________________________________
>> > Interest mailing list
>> > Interest at qt-project.org
>> > http://lists.qt-project.org/mailman/listinfo/interest
>>
>>
>> --
>> Regards,
>> Konstantin
>>
>
>
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>
>
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