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From: horstman@mathcs.sjsu.edu (Cay Horstmann)
Newsgroups: comp.lang.c++
Subject: Re: Why no renew
Message-ID: <1991Mar23.164302.10931@mathcs.sjsu.edu>
Date: 23 Mar 91 16:43:02 GMT
References: <281@nazgul.UUCP> <1991Mar14.042611.14921@mathcs.sjsu.edu> <12132@pasteur.Berkeley.EDU>
Organization: San Jose State University - Math/CS Dept.
Lines: 49

In article <12132@pasteur.Berkeley.EDU> jbuck@galileo.berkeley.edu (Joe Buck) writes:
>In article <1991Mar14.042611.14921@mathcs.sjsu.edu>, horstman@mathcs.sjsu.edu (Cay Horstmann) writes:
>|> I repeat my request that operator new should default to initializing the
>|> memory with the logical 0 value for the type allocated (almost always an
>|> all-0 bit pattern, but then who knows how 0 pointers or 0.0 floats are
>|> represented on some crazy systems.) ANSI, are you listening?
>
>How are you going to implement this?  operator new is handed a size_t
>object and returns an object of type void.  It doesn't know what type
>it's supposed to return.  Or do you want to make the "default" operator
>new special (preventing a user from writing something similar)?

I am not proposing to build this into operator new. Just like arrays of
classes get initialized AFTER operator new is called, arrays of non-class
objects would be initialized afterwards. You could still supply your
own global operator new. 

>
>Even if you could solve the technical problems, I'm still against it;
>it will just lead to lazy programming and subtle bugs (people will
>stop worrying about initializing every object member).

Now I agree it would be AWFUL if people started worrying about initia-
lizing every object member. For that reason, constructors should be BANNED
from the language.

Get real. Automatic initialization is one of the great features of C++. 
People have enough other things to worry about when writing programs.

>
>Next you'll be asking for a guarantee that when I write
>
>void foo (int arg1) {
>	char byteArray[BIGBUF];
>	int intArray[INTBUF];
>	...
>}
>
>that byteArray and intArray be initialized to all zeros as well.  If not,
>why not?  Why should creating an array with new be different from making
>automatic variables?

I am not going to argue this. It is not a problem I often have when pro-
gramming C++. It would be an incompatible change from C. I restrict my
request to operator new which doesn't exist in C, and for which an alter-
native exists (calling malloc) when the cost of zeroing out is considered
excessive. 

Cay