Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!lupine!rfg
From: rfg@NCD.COM (Ron Guilmette)
Newsgroups: comp.lang.c++
Subject: Re: value of 'this' in constructor
Message-ID: <1223@lupine.NCD.COM>
Date: 18 Aug 90 05:54:43 GMT
References: <12680@hydra.gatech.EDU>
Distribution: na
Organization: Network Computing Devices, Inc., Mt. View, CA
Lines: 25

In article <12680@hydra.gatech.EDU> gt3930b@prism.gatech.EDU (NICHOLS,STEVEN MALCOLM) writes:
<
<	Consider the following piece of code.  From p. 284 of "Using
<C++", and also p. 164 of "The C++ Programming Language", I am lead to 
<believe that the value of the pointer 'this', on entry to a constructor,
<will be 0 if the instance of the class has been dynamically allocated.
<If the class has been statically allocated, the value of 'this' will be
<non-zero.  However, I see non-zero values for this for both static and dynamic
<instances of the class test in the code fragment that follows. 
<	I see this behavior for both ZORTECH v. 2.06 on a 386 based PC, and
<a similar output for the same code compiled using Oregon C++ on a VMS based
<DEC micro-vax.  Since this is happening for *two* compilers, I conclude that
<I have misunderstood Eckel and Stroustrup when they described this feature.

Times change.  So do languages.  The old conventions regarding the value
of `this' upon entry to a constructor (which may assign to `this') don't apply
anymore.  A look at the newer "Annotated C++ Reference Manual" may help
you to understand the changes that "modern" C++ compilers are implementing
these days.

-- 

// Ron Guilmette  -  C++ Entomologist
// Internet: rfg@ncd.com      uucp: ...uunet!lupine!rfg
// Motto:  If it sticks, force it.  If it breaks, it needed replacing anyway.