Date: Fri, 01 Apr 2005 17:04:35 +0200 From: des@des.no (=?iso-8859-1?q?Dag-Erling_Sm=F8rgrav?=) To: standards@freebsd.org Subject: offsetof Message-ID: <86br8yr118.fsf@xps.des.no>
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I noticed that our definition of offsetof (in <sys/cdefs.h>) is as
follows:
#define __offsetof(type, field) ((size_t)(&((type *)0)->field))
This definition is gratuitously unportable (it assumes that a null
pointer is all-bits-zero). A better definition would be the
following:
#define __offsetof(type, field) \
((size_t)((char *)&((type *)0)->field - (char *)(type *)0))
DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no
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