[Qt-interest] About QScopedPointer

[Thiago Macieira]

On Friday, 13 de May de 2011 00:47:56 Mihail Naydenov wrote:
> I am in a bit of a struggle how to pass a pointer to a
> QScopedPointer-managed pointer.
> It seems impossible:
> 
> QScopedPointer<Data> d;
> 
> fund(void** data);  //< want to pass d into this

No, you don't.

You have a QScopedPointer<Data>, which is equivalent to Data*. One level of 
pointer.

That function takes a void**: two levels of pointers.

If you had a simple Data *d; you'd pass &d. That usually means that the called 
function would modify the pointer.

That's a really bad idea with QScopedPointer. It owns the pointer and you 
should not modify the value from underneath it.

> I guess QScopedPointer lacks a T*& data() member function. Is this going to
> be addressed. Or am I missing something.

No, it's not going to be addressed. That method can only be used to allow you 
to modify the pointer that QScopedPointer tracks without telling it.

You chose to use QScopedPointer so it would manage the pointers for you.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Senior Product Manager - Nokia, Qt Development Frameworks
      PGP/GPG: 0x6EF45358; fingerprint:
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