Re: Initialisation of reference vs. initialisation of reference member

From:
"Tim Clacy" <nospamtcl@nospamphaseone.nospamdk>
Newsgroups:
comp.lang.c++
Date:
Tue, 30 May 2006 15:01:07 +0200
Message-ID:
<447c4202$0$38678$edfadb0f@dread12.news.tele.dk>
shailesh wrote:

I tried running this:

   unsigned const int& n = 3;
   cout << n << endl;
   cout << &n << endl;

Output is:
3
0012FEC8

During debugging I can see that memory location 0012FEC8 has the value
3 stored.

This is on VC++ 2003 compiler.

So this answers question 1.

2:

About the error you saw, MSDN says this:
'reference' : initialization of reference member requires a temporary
variable

A constructor initializes a reference to a member instead of
initializing the member.

It is invalid to initialize a reference member of a class in the
class's constructor with a temporary variable. An attempt to do so
generates the C2354 error, as illustrated by this sample code:

// C2354.cpp
int temp() { return 1; }
class Test
{
public:
   int member;
   int& ref_member;
   Test();
};

Test::Test() : ref_member( temp() )
{ // C2354
}
When this error is encountered, the solution is to change the code so
that the reference member is not initialized to a temporary variable.
The reference must be initialized to an object that will exist for the
lifetime of the reference member.
------------------------------------------------------------------------------------

So it seems that the 2 in the constructor call is being treated as a
temporary variable. and not as something in the global memory.


Hi shailesh,

That's very interesting but the Microsoft compiler error that I saw was '
initialization of
reference member requires a temporary variable'. This is quite the opposite
of what the MSDN article says (reference member must NOT be initialised to a
temporary).

I'm a little more confused now :-(

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