DragonFly kernel List (threaded) for 2007-06
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#ifndef's before including the headers (redundant inclusion test?)

From:	"Nuno Antunes" <nuno.antunes@xxxxxxxxx>
Date:	Sun, 3 Jun 2007 21:17:32 +0100

Hi.

Why is the following test necessary before including headers? (for
example in sys/netgraph/netgraph.h).

#ifndef _SYS_QUEUE_H_
#include <sys/queue.h>
#endif

when <sys/queue.h> already tests for inclusion?

#ifndef _SYS_QUEUE_H_
#define _SYS_QUEUE_H_
. ..
#endif

Thanks,
Nuno

Follow-Ups:
- Re: #ifndef's before including the headers (redundant inclusion test?)
  - From: Matthew Dillon <dillon@apollo.backplane.com>