a162f659c6
From the redhat web page: http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/gcc/offsetof.html __offsetof__ (expression) is equivalent to the parenthesized expression, except that the expression is considered an integral constant expression even if it contains certain operators that are not normally permitted in an integral constant expression. Users should never use __offsetof__ directly; the only valid use of __offsetof__ is to implement the offsetof macro in <stddef.h>.
66 lines
2.4 KiB
C
66 lines
2.4 KiB
C
/* $NetBSD: stddef.h,v 1.13 2006/08/21 15:26:49 christos Exp $ */
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)stddef.h 8.1 (Berkeley) 6/2/93
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*/
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#ifndef _STDDEF_H_
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#define _STDDEF_H_
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#include <machine/ansi.h>
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typedef _BSD_PTRDIFF_T_ ptrdiff_t;
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#ifdef _BSD_SIZE_T_
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typedef _BSD_SIZE_T_ size_t;
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#undef _BSD_SIZE_T_
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#endif
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#ifdef _BSD_WCHAR_T_
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typedef _BSD_WCHAR_T_ wchar_t;
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#undef _BSD_WCHAR_T_
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#endif
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#include <sys/null.h>
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#if __GNUC__ >= 4
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#define offsetof(type, member) __builtin_offsetof(type, member)
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#elif !defined(__cplusplus)
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#define offsetof(type, member) ((size_t)(unsigned long)(&((type *)0)->member))
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#else
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#ifndef __offsetof__
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#define __offsetof__(a) a
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#endif
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#define offsetof(type, member) __offsetof__((reinterpret_cast<size_t> \
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(&reinterpret_cast<const volatile char &>(static_cast<type *>(0)->member))))
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#endif
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#endif /* _STDDEF_H_ */
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