llvm-project/libcxx/include/__config

624 lines
16 KiB
C++

// -*- C++ -*-
//===--------------------------- __config ---------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_CONFIG
#define _LIBCPP_CONFIG
#if !defined(_MSC_VER) || defined(__clang__)
#pragma GCC system_header
#endif
#ifdef __GNUC__
#define _GNUC_VER (__GNUC__ * 100 + __GNUC_MINOR__)
#endif
#define _LIBCPP_VERSION 1101
#define _LIBCPP_ABI_VERSION 1
#define _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_X##_LIBCPP_Y
#define _LIBCPP_CONCAT(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y)
#define _LIBCPP_NAMESPACE _LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION)
#ifdef __LITTLE_ENDIAN__
#if __LITTLE_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 1
#define _LIBCPP_BIG_ENDIAN 0
#endif // __LITTLE_ENDIAN__
#endif // __LITTLE_ENDIAN__
#ifdef __BIG_ENDIAN__
#if __BIG_ENDIAN__
#define _LIBCPP_LITTLE_ENDIAN 0
#define _LIBCPP_BIG_ENDIAN 1
#endif // __BIG_ENDIAN__
#endif // __BIG_ENDIAN__
#ifdef __FreeBSD__
# include <sys/endian.h>
# if _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 1
# define _LIBCPP_BIG_ENDIAN 0
# else // _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 0
# define _LIBCPP_BIG_ENDIAN 1
# endif // _BYTE_ORDER == _LITTLE_ENDIAN
# ifndef __LONG_LONG_SUPPORTED
# define _LIBCPP_HAS_NO_LONG_LONG
# endif // __LONG_LONG_SUPPORTED
#endif // __FreeBSD__
#ifdef __NetBSD__
# include <sys/endian.h>
# if _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 1
# define _LIBCPP_BIG_ENDIAN 0
# else // _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 0
# define _LIBCPP_BIG_ENDIAN 1
# endif // _BYTE_ORDER == _LITTLE_ENDIAN
# define _LIBCPP_HAS_QUICK_EXIT
#endif // __NetBSD__
#ifdef _WIN32
# define _LIBCPP_LITTLE_ENDIAN 1
# define _LIBCPP_BIG_ENDIAN 0
// Compiler intrinsics (GCC or MSVC)
# if defined(__clang__) \
|| (defined(_MSC_VER) && _MSC_VER >= 1400) \
|| (defined(__GNUC__) && _GNUC_VER > 403)
# define _LIBCPP_HAS_IS_BASE_OF
# endif
# if defined(_MSC_VER) && !defined(__clang__)
# define _LIBCPP_MSVC // Using Microsoft Visual C++ compiler
# define _LIBCPP_TOSTRING2(x) #x
# define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)
# define _LIBCPP_WARNING(x) __pragma(message(__FILE__ "(" _LIBCPP_TOSTRING(__LINE__) ") : warning note: " x))
# endif
# // If mingw not explicitly detected, assume using MS C runtime only.
# ifndef __MINGW32__
# define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
# endif
#endif // _WIN32
#ifdef __linux__
# if defined(__GNUC__) && _GNUC_VER >= 403
# define _LIBCPP_HAS_IS_BASE_OF
# endif
#endif
#ifdef __sun__
# include <sys/isa_defs.h>
# ifdef _LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 1
# define _LIBCPP_BIG_ENDIAN 0
# else
# define _LIBCPP_LITTLE_ENDIAN 0
# define _LIBCPP_BIG_ENDIAN 1
# endif
#endif // __sun__
#if !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)
# include <endian.h>
# if __BYTE_ORDER == __LITTLE_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 1
# define _LIBCPP_BIG_ENDIAN 0
# elif __BYTE_ORDER == __BIG_ENDIAN
# define _LIBCPP_LITTLE_ENDIAN 0
# define _LIBCPP_BIG_ENDIAN 1
# else // __BYTE_ORDER == __BIG_ENDIAN
# error unable to determine endian
# endif
#endif // !defined(_LIBCPP_LITTLE_ENDIAN) || !defined(_LIBCPP_BIG_ENDIAN)
#ifdef _WIN32
// only really useful for a DLL
#ifdef _LIBCPP_DLL // this should be a compiler builtin define ideally...
# ifdef cxx_EXPORTS
# define _LIBCPP_HIDDEN
# define _LIBCPP_FUNC_VIS __declspec(dllexport)
# define _LIBCPP_TYPE_VIS __declspec(dllexport)
# else
# define _LIBCPP_HIDDEN
# define _LIBCPP_FUNC_VIS __declspec(dllimport)
# define _LIBCPP_TYPE_VIS __declspec(dllimport)
# endif
#else
# define _LIBCPP_HIDDEN
# define _LIBCPP_FUNC_VIS
# define _LIBCPP_TYPE_VIS
#endif
#define _LIBCPP_TYPE_VIS_ONLY
#define _LIBCPP_FUNC_VIS_ONLY
#ifndef _LIBCPP_INLINE_VISIBILITY
# ifdef _LIBCPP_MSVC
# define _LIBCPP_INLINE_VISIBILITY __forceinline
# else // MinGW GCC and Clang
# define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__always_inline__))
# endif
#endif
#ifndef _LIBCPP_EXCEPTION_ABI
#define _LIBCPP_EXCEPTION_ABI _LIBCPP_TYPE_VIS
#endif
#ifndef _LIBCPP_ALWAYS_INLINE
# ifdef _LIBCPP_MSVC
# define _LIBCPP_ALWAYS_INLINE __forceinline
# endif
#endif
#endif // _WIN32
#ifndef __has_attribute
#define __has_attribute(__x) 0
#endif
#ifndef _LIBCPP_HIDDEN
#define _LIBCPP_HIDDEN __attribute__ ((__visibility__("hidden")))
#endif
#ifndef _LIBCPP_FUNC_VIS
#define _LIBCPP_FUNC_VIS __attribute__ ((__visibility__("default")))
#endif
#ifndef _LIBCPP_TYPE_VIS
# if __has_attribute(__type_visibility__)
# define _LIBCPP_TYPE_VIS __attribute__ ((__type_visibility__("default")))
# else
# define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
# endif
#endif
#ifndef _LIBCPP_TYPE_VIS_ONLY
# define _LIBCPP_TYPE_VIS_ONLY _LIBCPP_TYPE_VIS
#endif
#ifndef _LIBCPP_FUNC_VIS_ONLY
# define _LIBCPP_FUNC_VIS_ONLY _LIBCPP_FUNC_VIS
#endif
#ifndef _LIBCPP_INLINE_VISIBILITY
#define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__visibility__("hidden"), __always_inline__))
#endif
#ifndef _LIBCPP_EXCEPTION_ABI
#define _LIBCPP_EXCEPTION_ABI __attribute__ ((__visibility__("default")))
#endif
#ifndef _LIBCPP_ALWAYS_INLINE
#define _LIBCPP_ALWAYS_INLINE __attribute__ ((__visibility__("hidden"), __always_inline__))
#endif
#if defined(__clang__)
#if __has_feature(cxx_alignas)
# define _ALIGNAS_TYPE(x) alignas(x)
# define _ALIGNAS(x) alignas(x)
#else
# define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
# define _ALIGNAS(x) __attribute__((__aligned__(x)))
#endif
#if !__has_feature(cxx_alias_templates)
#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
#endif
#ifndef __GXX_EXPERIMENTAL_CXX0X__
#ifdef __linux__
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#else
typedef __char16_t char16_t;
typedef __char32_t char32_t;
#endif
#endif
#if !(__has_feature(cxx_exceptions))
#define _LIBCPP_NO_EXCEPTIONS
#endif
#if !(__has_feature(cxx_rtti))
#define _LIBCPP_NO_RTTI
#endif
#if !(__has_feature(cxx_strong_enums))
#define _LIBCPP_HAS_NO_STRONG_ENUMS
#endif
#if !(__has_feature(cxx_decltype))
#define _LIBCPP_HAS_NO_DECLTYPE
#endif
#if __has_feature(cxx_attributes)
# define _LIBCPP_NORETURN [[noreturn]]
#else
# define _LIBCPP_NORETURN __attribute__ ((noreturn))
#endif
#if !(__has_feature(cxx_defaulted_functions))
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#endif // !(__has_feature(cxx_defaulted_functions))
#if !(__has_feature(cxx_deleted_functions))
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
#endif // !(__has_feature(cxx_deleted_functions))
#if !(__has_feature(cxx_lambdas))
#define _LIBCPP_HAS_NO_LAMBDAS
#endif
#if !(__has_feature(cxx_nullptr))
#define _LIBCPP_HAS_NO_NULLPTR
#endif
#if !(__has_feature(cxx_rvalue_references))
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#endif
#if !(__has_feature(cxx_static_assert))
#define _LIBCPP_HAS_NO_STATIC_ASSERT
#endif
#if !(__has_feature(cxx_auto_type))
#define _LIBCPP_HAS_NO_AUTO_TYPE
#endif
#if !(__has_feature(cxx_access_control_sfinae)) || !__has_feature(cxx_trailing_return)
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#endif
#if !(__has_feature(cxx_variadic_templates))
#define _LIBCPP_HAS_NO_VARIADICS
#endif
#if !(__has_feature(cxx_trailing_return))
#define _LIBCPP_HAS_NO_TRAILING_RETURN
#endif
#if !(__has_feature(cxx_generalized_initializers))
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#endif
#if __has_feature(is_base_of)
# define _LIBCPP_HAS_IS_BASE_OF
#endif
// Objective-C++ features (opt-in)
#if __has_feature(objc_arc)
#define _LIBCPP_HAS_OBJC_ARC
#endif
#if __has_feature(objc_arc_weak)
#define _LIBCPP_HAS_OBJC_ARC_WEAK
#define _LIBCPP_HAS_NO_STRONG_ENUMS
#endif
#if !(__has_feature(cxx_constexpr))
#define _LIBCPP_HAS_NO_CONSTEXPR
#endif
#if __ISO_C_VISIBLE >= 2011 || __cplusplus >= 201103L
#if defined(__FreeBSD__)
#define _LIBCPP_HAS_QUICK_EXIT
#define _LIBCPP_HAS_C11_FEATURES
#elif defined(__linux__)
#include <features.h>
#if __GLIBC_PREREQ(2, 15)
#define _LIBCPP_HAS_QUICK_EXIT
#endif
#if __GLIBC_PREREQ(2, 17)
#define _LIBCPP_HAS_C11_FEATURES
#endif
#endif
#endif
#if (__has_feature(cxx_noexcept))
# define _NOEXCEPT noexcept
# define _NOEXCEPT_(x) noexcept(x)
# define _NOEXCEPT_OR_FALSE(x) noexcept(x)
#else
# define _NOEXCEPT throw()
# define _NOEXCEPT_(x)
# define _NOEXCEPT_OR_FALSE(x) false
#endif
#if __has_feature(underlying_type)
# define _LIBCXX_UNDERLYING_TYPE(T) __underlying_type(T)
#endif
// Inline namespaces are available in Clang regardless of C++ dialect.
#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD } }
#define _VSTD std::_LIBCPP_NAMESPACE
namespace std {
inline namespace _LIBCPP_NAMESPACE {
}
}
#elif defined(__GNUC__)
#define _ALIGNAS(x) __attribute__((__aligned__(x)))
#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
#define _LIBCPP_NORETURN __attribute__((noreturn))
#if !__EXCEPTIONS
#define _LIBCPP_NO_EXCEPTIONS
#endif
#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
#define _LIBCPP_HAS_NO_CONSTEXPR
#define _NOEXCEPT throw()
#define _NOEXCEPT_(x)
#define _NOEXCEPT_OR_FALSE(x) false
#ifndef __GXX_EXPERIMENTAL_CXX0X__
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#define _LIBCPP_HAS_NO_DECLTYPE
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
#define _LIBCPP_HAS_NO_NULLPTR
#define _LIBCPP_HAS_NO_STATIC_ASSERT
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_NO_VARIADICS
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#define _LIBCPP_HAS_NO_ALWAYS_INLINE_VARIADICS
#define _LIBCPP_HAS_NO_STRONG_ENUMS
#else // __GXX_EXPERIMENTAL_CXX0X__
#define _LIBCPP_HAS_NO_TRAILING_RETURN
#define _LIBCPP_HAS_NO_ALWAYS_INLINE_VARIADICS
#if _GNUC_VER < 403
#define _LIBCPP_HAS_NO_RVALUE_REFERENCES
#endif
#if _GNUC_VER < 403
#define _LIBCPP_HAS_NO_STATIC_ASSERT
#endif
#if _GNUC_VER < 404
#define _LIBCPP_HAS_NO_DECLTYPE
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_NO_VARIADICS
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#endif // _GNUC_VER < 404
#if _GNUC_VER < 406
#define _LIBCPP_HAS_NO_NULLPTR
#endif
#if _GNUC_VER < 407
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#endif
#endif // __GXX_EXPERIMENTAL_CXX0X__
#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD } }
#define _VSTD std::_LIBCPP_NAMESPACE
namespace std {
namespace _LIBCPP_NAMESPACE {
}
using namespace _LIBCPP_NAMESPACE __attribute__((__strong__));
}
#elif defined(_LIBCPP_MSVC)
#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
#define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#define _LIBCPP_HAS_NO_CONSTEXPR
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#define __alignof__ __alignof
#define _LIBCPP_NORETURN __declspec(noreturn)
#define _ALIGNAS(x) __declspec(align(x))
#define _LIBCPP_HAS_NO_VARIADICS
#define _NOEXCEPT throw()
#define _NOEXCEPT_(x)
#define _NOEXCEPT_OR_FALSE(x) false
#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {
#define _LIBCPP_END_NAMESPACE_STD }
#define _VSTD std
# define _LIBCPP_WEAK
namespace std {
}
#elif defined(__IBMCPP__)
#define _ALIGNAS(x) __attribute__((__aligned__(x)))
#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
#define _ATTRIBUTE(x) __attribute__((x))
#define _LIBCPP_NORETURN __attribute__((noreturn))
#define _NOEXCEPT throw()
#define _NOEXCEPT_(x)
#define _NOEXCEPT_OR_FALSE(x) false
#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
#define _LIBCPP_HAS_NO_ALWAYS_INLINE_VARIADICS
#define _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
#define _LIBCPP_HAS_NO_NULLPTR
#define _LIBCPP_HAS_NO_UNICODE_CHARS
#define _LIBCPP_HAS_IS_BASE_OF
#if defined(_AIX)
#define __MULTILOCALE_API
#endif
#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
#define _LIBCPP_END_NAMESPACE_STD } }
#define _VSTD std::_LIBCPP_NAMESPACE
namespace std {
inline namespace _LIBCPP_NAMESPACE {
}
}
#endif // __clang__ || __GNUC__ || _MSC_VER || __IBMCPP__
#ifdef _LIBCPP_HAS_NO_UNICODE_CHARS
typedef unsigned short char16_t;
typedef unsigned int char32_t;
#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
#ifdef _LIBCPP_HAS_NO_STATIC_ASSERT
template <bool> struct __static_assert_test;
template <> struct __static_assert_test<true> {};
template <unsigned> struct __static_assert_check {};
#define static_assert(__b, __m) \
typedef __static_assert_check<sizeof(__static_assert_test<(__b)>)> \
_LIBCPP_CONCAT(__t, __LINE__)
#endif // _LIBCPP_HAS_NO_STATIC_ASSERT
#ifdef _LIBCPP_HAS_NO_DECLTYPE
#define decltype(x) __typeof__(x)
#endif
#ifdef _LIBCPP_HAS_NO_CONSTEXPR
#define _LIBCPP_CONSTEXPR
#else
#define _LIBCPP_CONSTEXPR constexpr
#endif
#ifdef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
#define _LIBCPP_DEFAULT {}
#else
#define _LIBCPP_DEFAULT = default;
#endif
#ifdef __GNUC__
#define _NOALIAS __attribute__((__malloc__))
#else
#define _NOALIAS
#endif
#ifndef __has_feature
#define __has_feature(__x) 0
#endif
#if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__)
# define _LIBCPP_EXPLICIT explicit
#else
# define _LIBCPP_EXPLICIT
#endif
#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
#define _LIBCPP_DECLARE_STRONG_ENUM(x) struct _LIBCPP_TYPE_VIS x { enum __lx
#define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x) \
__lx __v_; \
_LIBCPP_ALWAYS_INLINE x(__lx __v) : __v_(__v) {} \
_LIBCPP_ALWAYS_INLINE explicit x(int __v) : __v_(static_cast<__lx>(__v)) {} \
_LIBCPP_ALWAYS_INLINE operator int() const {return __v_;} \
};
#else // _LIBCPP_HAS_NO_STRONG_ENUMS
#define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class _LIBCPP_TYPE_VIS x
#define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
#endif // _LIBCPP_HAS_NO_STRONG_ENUMS
#ifdef _LIBCPP_DEBUG
# if _LIBCPP_DEBUG == 0
# define _LIBCPP_DEBUG_LEVEL 1
# elif _LIBCPP_DEBUG == 1
# define _LIBCPP_DEBUG_LEVEL 2
# else
# error Supported values for _LIBCPP_DEBUG are 0 and 1
# endif
# define _LIBCPP_EXTERN_TEMPLATE(...)
#endif
#ifndef _LIBCPP_EXTERN_TEMPLATE
#define _LIBCPP_EXTERN_TEMPLATE(...)
#endif
#ifndef _LIBCPP_EXTERN_TEMPLATE2
#define _LIBCPP_EXTERN_TEMPLATE2(...) extern template __VA_ARGS__;
#endif
#if defined(__APPLE__) || defined(__FreeBSD__) || defined(_WIN32) || defined(__sun__) || defined(__NetBSD__)
#define _LIBCPP_LOCALE__L_EXTENSIONS 1
#endif
#ifdef __FreeBSD__
#define _DECLARE_C99_LDBL_MATH 1
#endif
#if defined(__APPLE__) || defined(__FreeBSD__)
#define _LIBCPP_HAS_DEFAULTRUNELOCALE
#endif
#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__sun__)
#define _LIBCPP_WCTYPE_IS_MASK
#endif
#ifndef _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
# define _LIBCPP_TRIVIAL_PAIR_COPY_CTOR 1
#endif
#ifndef _LIBCPP_STD_VER
# if __cplusplus <= 201103L
# define _LIBCPP_STD_VER 11
# else
# define _LIBCPP_STD_VER 13 // current year, or date of c++14 ratification
# endif
#endif // _LIBCPP_STD_VER
#if _LIBCPP_STD_VER > 11
#define _LIBCPP_DEPRECATED [[deprecated]]
#else
#define _LIBCPP_DEPRECATED
#endif
#if _LIBCPP_STD_VER <= 11
#define _LIBCPP_CONSTEXPR_AFTER_CXX11
#define _LIBCPP_EXPLICIT_AFTER_CXX11
#define _LIBCPP_DEPRECATED_AFTER_CXX11
#else
#define _LIBCPP_CONSTEXPR_AFTER_CXX11 constexpr
#define _LIBCPP_EXPLICIT_AFTER_CXX11 explicit
#define _LIBCPP_DEPRECATED_AFTER_CXX11 [[deprecated]]
#endif
// Try to find out if RTTI is disabled.
// g++ and cl.exe have RTTI on by default and define a macro when it is.
// g++ only defines the macro in 4.3.2 and onwards.
#if !defined(_LIBCPP_NO_RTTI)
# if defined(__GNUG__) && (__GNUC__ >= 4 && \
(__GNUC_MINOR__ >= 3 || __GNUC_PATCHLEVEL__ >= 2)) && !defined(__GXX_RTTI)
# define _LIBCPP_NO_RTTI
# elif (defined(_MSC_VER) && !defined(__clang__)) && !defined(_CPPRTTI)
# define _LIBCPP_NO_RTTI
# endif
#endif
#ifndef _LIBCPP_WEAK
# define _LIBCPP_WEAK __attribute__((__weak__))
#endif
#endif // _LIBCPP_CONFIG