Re: Initializing static reference (non-POD) member variables

"Alf P. Steinbach" <>
Tue, 24 Jul 2007 19:38:38 +0200
* Grey Alien:

Victor Bazarov wrote:

Grey Alien wrote:

class A
  A(const B& ref);

  static B& b ;

How may b be initialized ?

You need a static B object to initialise the reference with.

    .. // definitions of B and A classes.

    B bObj;
    B& A::b = bObj;

    int main()


Thanks, but what about the case where b dosesNOT have a default ctor -
and also, we need to initialize B with a SPECIFIC instance of B -
(example a database connection) - ie the instance called ref in my snippet.

An obvious way round this would be to use pointers rather than reference
types - but I just wanted to know whether there was a way to solve this
problem, using reference types instead of pointers.

The problem being:

1. Class A contains a static reference to Class B
2. Class B has no default ctor(s)
3. Class B's ctor takes a reference as one of its non-default arguments
4. The reference parameter required to construct B is provided via A's ctor

Is there a way to do this ?

Yes, but (1) that isn't what your code exemplifies, and (2)
initialization of non-local statics generally happens before main() is
called, and at that point you probably don't have any database
connection yet.

Why don't you explain what you're trying to achieve by using that "static"?

That solution is flawed, but if you explain what it's meant to be a
solution for, perhaps we can help with the Real Problem (TM).

A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
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