NetNews Usenet Archive 1992 #18/NN_1992_18.iso/spool/comp/lang/cplus/12601

Internet Message Format | 1992-08-19 | 1.6 KB

Path: sparky!uunet!ogicse!uwm.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!sunb10.cs.uiuc.edu!sparc10.cs.uiuc.edu!pjl
From: [e-mail] (Paul Lucas)
Newsgroups: comp.lang.c++
Subject: Re: Return value for the constructors.
Message-ID: <[e-mail]>
Date: 19 Aug 92 23:19:26 GMT
Article-I.D.: sunb10.1992Aug19.231926.28218
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
Sender: [e-mail]
Distribution: usa
Organization: University of Illinois at Urbana-Champaign
Lines: 22

In <[e-mail]> [e-mail] (Josh Mittleman) writes:

>[e-mail] (Paul Lucas) writes:

>*****>    No; the allocator new() is returning zero, not the constructor.
>>     Also, if the ctor further allocates it's own stuff, there is
>>     currently no clean way of returning that fact to the caller--
>>     new() will return success, i.e., non-zero.

>Sure there is: Overload operator new().  For example, give your class a
>static status flag.  operator new() sets it to 1, then calls ::new() to
>allocate the object.  Your constructors make whatever internal checks they
>need, and set status to 0 if there is a problem.  Then, operator new()
>returns a pointer to the new object or 0, depending on the success of the
>process.  From the users point-of-view, it simply looks like a normal call
>to new().

*****>    Clever...but it's not reentrant.
--
    - Paul J. Lucas                University of Illinois
      AT&T Bell Laboratories        at Urbana-Champaign
      Naperville, IL            [e-mail]