Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ulysses!hector!jss
From: jss@hector.UUCP (Jerry Schwarz)
Newsgroups: comp.lang.c++
Subject: Re: cfront 1.2.1 bug?
Keywords: is it a bug, or is it me?  is it fixed in 2.0?
Message-ID: <11517@ulysses.homer.nj.att.com>
Date: 11 May 89 13:52:32 GMT
References: <9640@watcgl.waterloo.edu>
Sender: netnews@ulysses.homer.nj.att.com
Reply-To: jss@hector.UUCP (Jerry Schwarz)
Distribution: comp
Organization: AT&T Bell Laboratories
Lines: 32

In article <9640@watcgl.waterloo.edu> al@watsup.waterloo.edu (Al Vermeulen) 
asks for help in understanding why some code fails to compile.

I have simplified his example slightly 

struct A { 
	A( A& ) ;  
};

void func2()
{
	A a; //  This declaration is rejected
}

C++ normally "synthesizes" two constructors for a class A.  The one
with no arguments and the one with an A& argument.  When you declare
any constructor  C++ assumes that you want to specify all the
constructors and therefore does not synthesize any.

The declaration of a requires such a constructor with no arguments.

To solve the problem you need to add a definition of the constructor
with no arguments.

struct A {
	A(A&) ;
	A() { } 
} ;


Jerry Schwarz
AT&T Bell Labs, Murray Hill