[Qt-interest] QSharedPointer and QMap/QHash

[Rudenko Eugene]

Thank you for reply, But It's not tiny way to implement qHash for every type of QSharedPointer<Class1>, QSharedPointer<Class2> and so on.  Is it only way?


> Hi,
> 
> Indeed, QHash can only handle keys with a class that has a qHash 
> function already. As you can see 
> (http://doc.trolltech.com/4.5/qhash.html) there are already a number of 
> such functions for the mose common types. You'll have to define your own 
> qHash function taking a QSharedPointer as argument and returning a uint. 
> You can for example return the result of qHash(sharedPointer.data()) 
> since there is a qHash function for the pointer type.
> 
> I hope this can help you.
> Regards,
> 
> Alex
> 
> 
> Rudenko Eugene a écrit :
>> Hello.
>> I'm trying to use QMap/QHash with QSharedPointer with no success.
>> 
>> For example, such code:
>> ===============================
>> class MyClass : QObject {
>> Q_OBJECT
>> ..........
>> QMap< QSharedPointer<MyClass>, int > mm;  //or QHash
>> }
>> 
>> 
>> ........
>> QSharedPointer<MyClass> a = b.getPointer();
>> mm.insert(a,0);
>> 
>> ===============================
>> I have got error:
>> in case of use QHash:
>> no matching function to call to 'qHash(const QSharedPointer<MyClass> & )'
>> candidates: ..........
>> 
>> 
>> in case of use QMap:
>> no match for 'operator<' in 'key1 < key2'
>> candidates are ........
>> 
>> 
>> As I can see, there are no overloaded operators "<" and "qHash" for QSharedPointer, to redirect it to containing object.
>> As I can understand, QSharedPointer is not suitable to use with QMap and QHash, Is I right?
>> How can I use container classes with smart pointer classes ?
>> 
>> 
>> With best regards, Eugene Rudenko.
>> 
>> 
>> 
>> 
>> 
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>> 
> 
> 
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