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From: Glynn Clements <glynn@gclements.plus.com>
To: gumbold@bonbon.net
Cc: linux-c-programming@vger.kernel.org
Subject: Re: data structure question
Date: Sun, 15 May 2005 12:02:17 +0100	[thread overview]
Message-ID: <17031.11321.223828.203914@gargle.gargle.HOWL> (raw)
In-Reply-To: <42871714.5060007@bonbon.net>


gumbold wrote:

> why somebody wants to write such thing
> struct abc {
>     __u16 a;
>     __u16 b;
>     char abc[0];
> } __attribute__((packed));
> Specialy for zerod array of chars.

A structure which ends with a zero-length array is intended for use as
the "header" for a variable-sized block of data, e.g.:

	struct abc *new_abc(__u16 a, __u16 b, const char *string)
	{
		int len = strlen(string);
		struct abc *p = malloc(sizeof(struct abc) + len + 1);
	
		p->a = a;
		p->b = b;
		memcpy(p->abc, string, len + 1);
	
		return p;
	}

-- 
Glynn Clements <glynn@gclements.plus.com>

  reply	other threads:[~2005-05-15 11:02 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-15  9:32 data structure question gumbold
2005-05-15 11:02 ` Glynn Clements [this message]
2005-05-15 11:24   ` gumbold
2005-05-15 14:23     ` Glynn Clements
2005-05-16  4:00       ` gumbold
2005-05-16 15:28         ` Glynn Clements
2005-05-16 18:31           ` gumbold
2005-05-17  7:36             ` Glynn Clements
2005-05-16 19:07           ` gumbold

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