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Re: Second draft, "Safe arrays and pointers for C"

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On 2012-09-03, BGB <cr88192@hotmail.com> wrote:
> On 9/2/2012 3:20 PM, Hans-Bernhard Br?ker wrote:
>> On 01.09.2012 02:26, John Nagle wrote:
>>
>>>     Not really.  The main use case for unions is for data read
>>> in from an external source, often a network.
>>
>> No, it's not, because the vast majority of usages of unions for that
>> purpose would automatically cause undefined behaviour.
>>
>
> yeah, and also most cases I have seen unions used for have little to do 
> with network data.
>
>
>>>     Tightening down the screws further on that would alienate too many C
>>> programmers.  Consider the common idiom
>>>
>>>     const char* msg[] =
>>>     {"First message", "second message", "third message", 0 }
>>
>
> (ironically, the above will probably only work without issue in C++, and 
> in C will usually generate a message something like "warning: int to 
> pointer conversion without a cast" or similar... this means the array 
> needs to be terminated with either NULL or "((void *)0)" or "((char 
> *)0)" or similar to avoid the compiler complaining about it).

In C, 0 is perfectly fine as a char* (it's a null pointer constant).
Have you really seen warnings for this?

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Second draft, "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-30 12:48 -0700
  Re: Second draft, "Safe arrays and pointers for C" pacman@kosh.dhis.org (Alan Curry) - 2012-08-31 22:17 +0000
    Re: Second draft, "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-08-31 17:26 -0700
      Re: Second draft, "Safe arrays and pointers for C" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-09-02 22:20 +0200
        Re: Second draft, "Safe arrays and pointers for C" BGB <cr88192@hotmail.com> - 2012-09-03 10:55 -0500
          Re: Second draft, "Safe arrays and pointers for C" Ike Naar <ike@iceland.freeshell.org> - 2012-09-03 16:39 +0000
            Re: Second draft, "Safe arrays and pointers for C" BGB <cr88192@hotmail.com> - 2012-09-03 13:18 -0500
  Re: Second draft, "Safe arrays and pointers for C" Jens Gustedt <jens.gustedt@loria.fr> - 2012-09-02 10:52 +0200
  Re: Second draft, "Safe arrays and pointers for C" Per <per.mathisen@gmail.com> - 2012-09-28 06:49 -0700
    Re: Second draft, "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-09-28 11:36 -0700
      Re: Second draft, "Safe arrays and pointers for C" Per <per.mathisen@gmail.com> - 2012-10-01 09:38 -0700
        Re: Second draft, "Safe arrays and pointers for C" John Nagle <nagle@animats.com> - 2012-10-01 11:38 -0700
      Re: Second draft, "Safe arrays and pointers for C" Shao Miller <sha0.miller@gmail.com> - 2012-12-17 09:11 -0500
        Re: Second draft, "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-12-17 10:18 -0800
          Re: Second draft, "Safe arrays and pointers for C" Shao Miller <sha0.miller@gmail.com> - 2012-12-17 18:24 -0500
            Re: Second draft, "Safe arrays and pointers for C" Shao Miller <sha0.miller@gmail.com> - 2012-12-17 18:32 -0500
            Re: Second draft, "Safe arrays and pointers for C" Keith Thompson <kst-u@mib.org> - 2012-12-17 15:44 -0800

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