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From: michi1@michaelblizek.twilightparadox.com (michi1 at michaelblizek.twilightparadox.com)
To: kernelnewbies@lists.kernelnewbies.org
Subject: [RFC]confusions about 'struct' define
Date: Thu, 31 May 2012 18:40:20 +0200	[thread overview]
Message-ID: <20120531164019.GA2256@grml> (raw)
In-Reply-To: <CAD+1EGNbNqZSnO54NDRO083NEmGUXoetmwLE67cGh0Y55mkRVg@mail.gmail.com>

Hi!

On 00:50 Thu 31 May     , harryxiyou wrote:
...
> I have never seen struct define like
> 
> "struct device;
> struct device_private;
> struct device_driver;
> [...]
> struct device_node;
> struct iommu_ops;"

This basically says that these structs exist and are defined somewhere. You
need this basically for things like this:

struct b;

struct a{
	struct b *b_ptr;
};

struct b{
	struct a *a_ptr;
};

The struct can only be dereferenced after it is defined. Also, the storage
size is unknown, so the same applies to inlining and sizeof().

	-Michi
-- 
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com

  parent reply	other threads:[~2012-05-31 16:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-30 16:50 [RFC]confusions about 'struct' define harryxiyou
2012-05-30 17:20 ` Gaurav Jain
2012-05-30 17:37   ` harryxiyou
2012-06-01  9:30     ` Bernd Petrovitsch
2012-06-04 14:18       ` Sarbojit Ganguly
2012-05-31 16:40 ` michi1 at michaelblizek.twilightparadox.com [this message]
  -- strict thread matches above, loose matches on Subject: below --
2012-05-30 18:41 Rajat Sharma

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