From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: Ian Pilcher <arequipeno@gmail.com>
Cc: gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: Flexible array member initializers
Date: Wed, 08 Jan 2014 22:21:00 -0000 [thread overview]
Message-ID: <CAH6eHdRq9-TiWBS+R6=TQL7D4c7s+cHaAqEw4e_oP5T2PkZGjA@mail.gmail.com> (raw)
In-Reply-To: <52CDC7C8.5070804@gmail.com>
On 8 January 2014 21:48, Ian Pilcher wrote:
> On 01/08/2014 04:42 PM, Jonathan Wakely wrote:
>>>
>>> #define SHORT_BYTES(s) { ((s) & 0xff), (((s) >> 8) & 0xff) }
>>>
>>> struct foo {
>>> size_t value_size;
>>> unsigned char value[];
>>> };
>>>
>>> static struct foo foo_short = {
>>> .value_size = sizeof(short),
>>> .value = SHORT_BYTES(513),
>>> };
>>
>>
>> Where do you think those two bytes are meant to be stored?
>>
>
> Maybe I don't understand your question, but the two bytes that make up
> the short get stored in the "value" element (as an array of 2 unsigned
> characters).
The point of my question is that the 'value' member is an incomplete
type, it does not have any storage, so there is nowhere to store those
two bytes.
But I didn't realise GCC has a non-standard extension that does allow
what you're doing, automatically allocating space after the struct:
http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
next prev parent reply other threads:[~2014-01-08 22:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 5:13 Ian Pilcher
2014-01-08 8:59 ` Jonathan Wakely
2014-01-08 20:41 ` Ian Pilcher
2014-01-08 21:00 ` Marc Glisse
2014-01-08 21:46 ` Ian Pilcher
2014-01-08 21:43 ` Jonathan Wakely
2014-01-08 21:49 ` Ian Pilcher
2014-01-08 22:21 ` Jonathan Wakely [this message]
2014-01-08 23:23 ` Ángel González
2014-01-11 2:03 ` Ian Pilcher
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