Re: private data access in constructors
Greg Herlihy wrote:
Jiang wrote:
That was also my first thought, but I found the constructor
chain is possible under the current c++ rules. It is maybe
a hole, but as James & Francis said in this thread, the
usage could be used for some very special scenarios.
Maybe not for much longer. Constructing an object with the object's own
value (but not its address) may not be legal in C++0x:
int i = i; // Ill-formed, diagnostic required
void* p = &p; // Okay
See: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#504
Thanks for the pointer, quite reasonable, right?
Well, lest go back to the original question. For this issue I believe
that compared with initialize the member in the initializer list,
assignment in the constructor seems a better solution, because
we still have chance for checking( meaningless? maybe :-) ).
$ cat cc.cpp
struct X
{
X(const X& obj){
if(this == &obj ){
throw(exception("What are you doing now?"));
}
i = obj.i;
}
int i; // resources
};
int main()
{
X x(x);
}
The point is, for initializer list, everything is dominated by
compiler. If we need some special preprocessing (precondition
checking, etc..), assignment in constructor works just fine.
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