CODEWITHSUNDEEP
c++qttypesvector
Ashot
Ashot

Reputation: 10969

Size method of QVector and std::vector

The size method of QVector is of type int, but the same method in std::vector is unsigned. Why is the difference. Isn't unsigned type the right way to hold size, since it can't be negative?

Upvotes: 4

Views: 955

Answers (1)

Zeta
Zeta

Reputation: 105885

Because they discussed it in 1999 and got to the conclusion that int is a better choice, since the number of functions returning uint was relatively small and they were displeased by the warnings:

Subject: Re: killing uint as return type in Qt.
From: Alex Sandro Queiroz e Silva <asandro@xxxxxxxxxxxxx>
Date: Wed, 17 Mar 1999 15:29:37 -0300 (EST)
Cc: qt-interest@xxxxxxxx
To: Arnt Gulbrandsen <arnt@xxxxxxxx>

On 17 Mar 1999, Arnt Gulbrandsen wrote:

About 0.15% of the functions in Qt return uint. Most of those are called QMumble::size() or QMumble::count(). These functions never need to return a negative number, so really, uint is the right type for them to return.

But it's a nuisance, to me at least. I keep comparing them with ints, putting them in variables that -can- contain negative numbers, and so on. I've written

 if ( blah->count() < i )

and gotten compiler warning too many times already.

So I am considering changing the return type for these functions to int in Qt 2.0. What do you think? You're the users - do you want correctness and total backward compatibility or would you prefer more convenience?

--Arnt

I think this time convenience is better, we all now the kind of results we may get from this methos, so...

-- Alex [email protected]

Upvotes: 6

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