Return value to QList

I have a method that returns a QList<int>.

some possibilities:
- QList is returned filled with ints. OK.
- QList returns empty, but because no ints were put in it.

but the method might result in error, and I have to return it nonetheless.
right now, I'm returning a empty QList, but its no good, since a empty QList is possible to happen without error.

I tryed returning 'NULL', but C++ won't let me.
I thought of returning a QList with the first element set to -1, but that's lame.

What can I return instead?
I'd rather not use Exceptions...

thankyou

think on an impossible value and add it to the list. If the list has only that value, it's like empty.

What about a "bool* ok" function argument?

IF you want to test for NULL then you might try returning a QList<int> *.


jw
sw developer

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think on an impossible value and add it to the list. If the list has only that value, it's like empty.

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that's what I thought when I said about returning the first element set as -1... but, that's so... not elegant. :p

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What about a "bool* ok" function argument?

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I can't change any arguments, but maybe I can use that sugestion somewhere else. thanks

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IF you want to test for NULL then you might try returning a QList<int> *.

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if you meant

Code:

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return QList<int> *;

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that doesn't work. I've got nooo idea why.

thank you all, I think I'll have to rely in 'not elegant' methods XD

The "bool *ok" solution is the best. If you can't alter the arguments but you can alter the returned value you can use

Code:

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QPair<bool, QList<int> > returnListFunction() {}

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Originally Posted by lyucs

What can I return instead?

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You can return an empty list and besides that have a "lastError" method in your class to determine if the last call was successful or not. Qt uses this approach in many places as an alternative to exceptions.

I use a public bool variable in the class, than, set it in the beginning of the method and change it if the error occur. After calling the method, I check the flag value.