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Re: is this legal (and ANSI89 conforming) C?

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On 6/23/2011 06:47, Ben Bacarisse wrote:
> Shao Miller<sha0.miller@gmail.com>  writes:
>
>> On 6/22/2011 8:57 PM, Eric Sosman wrote:
>>> On 6/22/2011 2:35 PM, Tom St Denis wrote:
>>>> On Jun 22, 1:26 pm, "dr.oktopus"<blindwi...@freeonline.zzn.com>
>>>> wrote:
>>>>> Hello,
>>>>> suppose that I have to create a dummy node of a list data type
>>>>> that references itself (like in Sedgewick book). Is this:
>>>>>
>>>>> struct node {
>>>>> struct node *next;
>>>>> int c;
>>>>>
>>>>> } dummy_node = {&dummy_node };
>>>>>
>>>>> legal? I think no problem should be, but I want a confirm.
>>>>
>>>> IIRC it's valid because once you declare the variable you can use it
>>>> right away.
>>>
>>> Yes. The scope of the identifier `node' begins immediately
>>> after its first appearance, so it's in scope when mentioned on
>>> the next line. The scope of the identifier `dummy_node' begins
>>> immediately after its declarator (that is, just before the `='),
>>> so it's in scope when used in the initializer.
>>>
>>
>> I could be mistaken, but for C89:
>>
>> - I believe that an initializer for a 'struct', 'union', or array must
>> be a constant expression.
>>
>> - I believe that '&dummy_node' is not an address constant because
>> dummy_node' is not an object with 'static' storage duration.
>
> You don't know it doesn't!  The code is, presumably, intended to be at
> file scope (if I can mix usages for a moment) so 'dummy_node' will be an
> object with static storage duration.
>

"Create" and "dummy_node" give me the impression that it is within a 
function.  As always, I could be mistaken.  Perhaps dr.oktopus could 
clarify?

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is this legal (and ANSI89 conforming) C? "dr.oktopus" <blindwilly@freeonline.zzn.com> - 2011-06-22 10:26 -0700
  Re: is this legal (and ANSI89 conforming) C? Tom St Denis <tom@iahu.ca> - 2011-06-22 11:35 -0700
    Re: is this legal (and ANSI89 conforming) C? BGB <cr88192@hotmail.com> - 2011-06-22 12:49 -0700
      Re: is this legal (and ANSI89 conforming) C? Angel <angel+news@spamcop.net> - 2011-06-22 20:00 +0000
      Re: is this legal (and ANSI89 conforming) C? Tom St Denis <tom@iahu.ca> - 2011-06-22 13:39 -0700
        Re: is this legal (and ANSI89 conforming) C? BGB <cr88192@hotmail.com> - 2011-06-22 15:22 -0700
    Re: is this legal (and ANSI89 conforming) C? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-22 21:57 -0400
      Re: is this legal (and ANSI89 conforming) C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-23 11:47 +0100
        Re: is this legal (and ANSI89 conforming) C? Shao Miller <sha0.miller@gmail.com> - 2011-06-23 08:28 -0400
          Re: is this legal (and ANSI89 conforming) C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-23 14:08 +0100
          Re: is this legal (and ANSI89 conforming) C? "dr.oktopus" <blindwilly@freeonline.zzn.com> - 2011-06-24 12:36 -0700
            Re: is this legal (and ANSI89 conforming) C? Shao Miller <sha0.miller@gmail.com> - 2011-06-24 16:01 -0400
              Re: is this legal (and ANSI89 conforming) C? "dr.oktopus" <blindwilly@freeonline.zzn.com> - 2011-06-25 13:08 -0700
                Re: is this legal (and ANSI89 conforming) C? James Kuyper <jameskuyper@verizon.net> - 2011-06-25 19:02 -0400
  Re: is this legal (and ANSI89 conforming) C? Shao Miller <sha0.miller@gmail.com> - 2011-06-22 19:24 -0500
    Re: is this legal (and ANSI89 conforming) C? Shao Miller <sha0.miller@gmail.com> - 2011-06-22 19:34 -0500
  Re: is this legal (and ANSI89 conforming) C? Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-23 01:15 -0700
  Re: is this legal (and ANSI89 conforming) C? James Kuyper <jameskuyper@verizon.net> - 2011-06-23 06:15 -0400

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