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From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: constructor calls constructor?
Keywords: constructors, this
Message-ID: <9396@alice.UUCP>
Date: 26 May 89 23:07:07 GMT
References: <601@rna.UUCP>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 30

In article <601@rna.UUCP>, kc@rna.UUCP (Kaare Christian) writes:

> Is there a way for one constructor to call another, simply to have
> some chores performed, while avoiding real construction?

Nope.  Roundabout or not, the best way to do it is with
helper functions.

However, if you really insist, C++ 2.0 will have a way to say
`construct an object of type T at location X," as follows:

	new (X) T (args);

So by saying

	new (this) T (args);

you will, in effect, be able to call one constructor from another.
Having called this operator new, you'll need to define it:

	void* operator new(size_t,T* tp) { return tp; }

and then you're in business.

I said `if you really insist' because I think it's conceptually
cleaner to use helper functions and it is probably worthwhile
not to cut yourself off from older C++ implementations.
-- 
				--Andrew Koenig
				  ark@europa.att.com