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/** @file
* IPRT - Compile Time Assertions.
*/
/*
* Copyright (C) 2006-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
#ifndef IPRT_INCLUDED_assertcompile_h
#define IPRT_INCLUDED_assertcompile_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif
#include <iprt/cdefs.h>
/** @defgroup grp_rt_assert_compile Compile time assertions
* @ingroup grp_rt
*
* These assertions are used to check structure sizes, member/size alignments
* and similar compile time expressions.
*
* @remarks As you might have noticed, the AssertCompile macros don't follow the
* coding guidelines wrt to macros supposedly being all uppercase and
* underscored. For various reasons they don't, and nobody has
* complained yet.
*
* @{
*/
/**
* RTASSERTTYPE is the type the AssertCompile() macro redefines.
* It has no other function and shouldn't be used.
* Visual C++ uses this.
*/
typedef int RTASSERTTYPE[1];
/**
* RTASSERTVAR is the type the AssertCompile() macro redefines.
* It has no other function and shouldn't be used.
* GCC uses this.
*/
#ifdef __GNUC__
RT_C_DECLS_BEGIN
#endif
extern int RTASSERTVAR[1];
#ifdef __GNUC__
RT_C_DECLS_END
#endif
/** @def RTASSERT_HAVE_STATIC_ASSERT
* Indicates that the compiler implements static_assert(expr, msg).
*/
#ifdef _MSC_VER
# if _MSC_VER >= 1600 && defined(__cplusplus)
# define RTASSERT_HAVE_STATIC_ASSERT
# endif
#endif
#if defined(__GNUC__) && defined(__GXX_EXPERIMENTAL_CXX0X__)
# define RTASSERT_HAVE_STATIC_ASSERT
#endif
#if RT_CLANG_PREREQ(6, 0)
# if __has_feature(cxx_static_assert) || __has_feature(c_static_assert)
# define RTASSERT_HAVE_STATIC_ASSERT
# endif
#endif
#ifdef DOXYGEN_RUNNING
# define RTASSERT_HAVE_STATIC_ASSERT
#endif
/** @def AssertCompileNS
* Asserts that a compile-time expression is true. If it's not break the build.
*
* This differs from AssertCompile in that it accepts some more expressions
* than what C++0x allows - NS = Non-standard.
*
* @param expr Expression which should be true.
*/
#ifdef __GNUC__
# define AssertCompileNS(expr) extern int RTASSERTVAR[1] __attribute__((__unused__)), RTASSERTVAR[(expr) ? 1 : 0] __attribute__((__unused__))
#elif defined(__IBMC__) || defined(__IBMCPP__)
# define AssertCompileNS(expr) extern int RTASSERTVAR[(expr) ? 1 : 0]
#else
# define AssertCompileNS(expr) typedef int RTASSERTTYPE[(expr) ? 1 : 0]
#endif
/** @def AssertCompile
* Asserts that a C++0x compile-time expression is true. If it's not break the
* build.
* @param expr Expression which should be true.
*/
#ifdef RTASSERT_HAVE_STATIC_ASSERT
# ifdef __cplusplus
# define AssertCompile(expr) static_assert(!!(expr), #expr)
# else
# define AssertCompile(expr) _Static_assert(!!(expr), #expr)
# endif
#else
# define AssertCompile(expr) AssertCompileNS(expr)
#endif
/** @def RTASSERT_OFFSET_OF()
* A offsetof() macro suitable for compile time assertions.
* Both GCC v4 and VisualAge for C++ v3.08 has trouble using RT_OFFSETOF.
*/
#if defined(__GNUC__)
# if __GNUC__ >= 4
# define RTASSERT_OFFSET_OF(a_Type, a_Member) __builtin_offsetof(a_Type, a_Member)
# else
# define RTASSERT_OFFSET_OF(a_Type, a_Member) RT_OFFSETOF(a_Type, a_Member)
# endif
#elif (defined(__IBMC__) || defined(__IBMCPP__)) && defined(RT_OS_OS2)
# define RTASSERT_OFFSET_OF(a_Type, a_Member) __offsetof(a_Type, a_Member)
#elif (defined(__WATCOMC__) && defined(__cplusplus))
# define RTASSERT_OFFSET_OF(a_Type, a_Member) __offsetof(a_Type, a_Member)
#else
# define RTASSERT_OFFSET_OF(a_Type, a_Member) RT_OFFSETOF(a_Type, a_Member)
#endif
/** @def AssertCompileSize
* Asserts a size at compile.
* @param type The type.
* @param size The expected type size.
*/
#define AssertCompileSize(type, size) \
AssertCompile(sizeof(type) == (size))
/** @def AssertCompileSizeAlignment
* Asserts a size alignment at compile.
* @param type The type.
* @param align The size alignment to assert.
*/
#define AssertCompileSizeAlignment(type, align) \
AssertCompile(!(sizeof(type) & ((align) - 1)))
/** @def AssertCompileMemberSize
* Asserts a member offset alignment at compile.
* @param type The type.
* @param member The member.
* @param size The member size to assert.
*/
#define AssertCompileMemberSize(type, member, size) \
AssertCompile(RT_SIZEOFMEMB(type, member) == (size))
/** @def AssertCompileMemberSizeAlignment
* Asserts a member size alignment at compile.
* @param type The type.
* @param member The member.
* @param align The member size alignment to assert.
*/
#define AssertCompileMemberSizeAlignment(type, member, align) \
AssertCompile(!(RT_SIZEOFMEMB(type, member) & ((align) - 1)))
/** @def AssertCompileMemberAlignment
* Asserts a member offset alignment at compile.
* @param type The type.
* @param member The member.
* @param align The member offset alignment to assert.
*/
#define AssertCompileMemberAlignment(type, member, align) \
AssertCompile(!(RTASSERT_OFFSET_OF(type, member) & ((align) - 1)))
/** @def AssertCompileMemberOffset
* Asserts an offset of a structure member at compile.
* @param type The type.
* @param member The member.
* @param off The expected offset.
*/
#define AssertCompileMemberOffset(type, member, off) \
AssertCompile(RTASSERT_OFFSET_OF(type, member) == (off))
/** @def AssertCompile2MemberOffsets
* Asserts that two (sub-structure) members in union have the same offset.
* @param type The type.
* @param member1 The first member.
* @param member2 The second member.
*/
#define AssertCompile2MemberOffsets(type, member1, member2) \
AssertCompile(RTASSERT_OFFSET_OF(type, member1) == RTASSERT_OFFSET_OF(type, member2))
/** @def AssertCompileAdjacentMembers
* Asserts that two structure members are adjacent.
* @param type The type.
* @param member1 The first member.
* @param member2 The second member.
*/
#define AssertCompileAdjacentMembers(type, member1, member2) \
AssertCompile(RTASSERT_OFFSET_OF(type, member1) + RT_SIZEOFMEMB(type, member1) == RTASSERT_OFFSET_OF(type, member2))
/** @def AssertCompileMembersAtSameOffset
* Asserts that members of two different structures are at the same offset.
* @param type1 The first type.
* @param member1 The first member.
* @param type2 The second type.
* @param member2 The second member.
*/
#define AssertCompileMembersAtSameOffset(type1, member1, type2, member2) \
AssertCompile(RTASSERT_OFFSET_OF(type1, member1) == RTASSERT_OFFSET_OF(type2, member2))
/** @def AssertCompileMembersSameSize
* Asserts that members of two different structures have the same size.
* @param type1 The first type.
* @param member1 The first member.
* @param type2 The second type.
* @param member2 The second member.
*/
#define AssertCompileMembersSameSize(type1, member1, type2, member2) \
AssertCompile(RT_SIZEOFMEMB(type1, member1) == RT_SIZEOFMEMB(type2, member2))
/** @def AssertCompileMembersSameSizeAndOffset
* Asserts that members of two different structures have the same size and are
* at the same offset.
* @param type1 The first type.
* @param member1 The first member.
* @param type2 The second type.
* @param member2 The second member.
*/
#define AssertCompileMembersSameSizeAndOffset(type1, member1, type2, member2) \
AssertCompile( RTASSERT_OFFSET_OF(type1, member1) == RTASSERT_OFFSET_OF(type2, member2) \
&& RT_SIZEOFMEMB(type1, member1) == RT_SIZEOFMEMB(type2, member2))
/** @} */
#endif /* !IPRT_INCLUDED_assertcompile_h */