Path: utzoo!attcan!uunet!husc6!uwvax!tank!uxc!uxc.cso.uiuc.edu!m.cs.uiuc.edu!grunwald
From: grunwald@m.cs.uiuc.edu
Newsgroups: comp.lang.c++
Subject: Re: Managing C++ Libraries: Using +e0 a
Message-ID: <4800042@m.cs.uiuc.edu>
Date: 3 Nov 88 17:17:00 GMT
References: <4981@thorin.cs.unc.edu>
Lines: 26
Nf-ID: #R:thorin.cs.unc.edu:4981:m.cs.uiuc.edu:4800042:000:614
Nf-From: m.cs.uiuc.edu!grunwald    Nov  3 11:17:00 1988


The problem with +e0 is that if a library routine has something like:

--Bar.h--
class Foo;

class Bar {
	Foo *instance
public:
	Bar()
}

--Bar.cc--
Bar::Bar()
{
	instance = new Foo;
}

and you compile Bar.cc with +e0, and your program never references ``Foo.h'',
your constructor doesn't get created.

This is one of the problems of compiling directly to C code. You really
want to pass information to the loader in the form of ``stabs'' or COFF
info saying ``hey, I'm using class Foo'' and ``Foo has the following vtbl''.
Then, the loader can sort through these entries, producing a single vtbl
at compile time.