boost/hana/config.hpp

0001 /*!
0002 @file
0003 Defines configuration macros used throughout the library.
0004
0005 Copyright Louis Dionne 2013-2022
0006 Distributed under the Boost Software License, Version 1.0.
0007 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
0008  */
0009
0010 #ifndef BOOST_HANA_CONFIG_HPP
0011 #define BOOST_HANA_CONFIG_HPP
0012
0013 #include <boost/hana/version.hpp>
0014
0015
0016 //////////////////////////////////////////////////////////////////////////////
0017 // Detect the compiler
0018 //////////////////////////////////////////////////////////////////////////////
0019
0020 #if defined(_MSC_VER) && !defined(__clang__) // MSVC
0021     // This must be checked first, because otherwise it produces a fatal
0022     // error due to unrecognized #warning directives used below.
0023
0024 #   if _MSC_VER < 1915
0025 #       pragma message("Warning: the native Microsoft compiler is not supported due to lack of proper C++14 support.")
0026 #   else
0027         // 1. Active issues
0028         // Multiple copy/move ctors
0029 #       define BOOST_HANA_WORKAROUND_MSVC_MULTIPLECTOR_106654
0030
0031         // 2. Issues fixed in the development branch of MSVC
0032         // Forward declaration of class template member function returning decltype(auto)
0033 #       define BOOST_HANA_WORKAROUND_MSVC_DECLTYPEAUTO_RETURNTYPE_662735
0034
0035         // 3. Issues fixed conditionally
0036         // Requires __declspec(empty_bases)
0037         // Empty base optimization
0038 #       define BOOST_HANA_WORKAROUND_MSVC_EMPTYBASE
0039
0040         // Requires /experimental:preprocessor
0041         // Variadic macro expansion
0042 #       if !defined(_MSVC_TRADITIONAL) || _MSVC_TRADITIONAL
0043 #           define BOOST_HANA_WORKAROUND_MSVC_PREPROCESSOR_616033
0044 #       endif
0045 #   endif
0046
0047 #elif defined(__clang__) && defined(_MSC_VER) // Clang-cl (Clang for Windows)
0048
0049 #   define BOOST_HANA_CONFIG_CLANG_CL
0050 #   define BOOST_HANA_CONFIG_CLANG BOOST_HANA_CONFIG_VERSION(               \
0051                     __clang_major__, __clang_minor__, __clang_patchlevel__)
0052
0053 #elif defined(__clang__) && defined(__apple_build_version__) // Apple's Clang
0054
0055 #   define BOOST_HANA_CONFIG_APPLE_CLANG
0056 #   if __apple_build_version__ >= 6020049
0057 #       define BOOST_HANA_CONFIG_CLANG BOOST_HANA_CONFIG_VERSION(3, 6, 0)
0058 #   endif
0059
0060 #elif defined(__clang__) // genuine Clang
0061
0062 #   define BOOST_HANA_CONFIG_CLANG BOOST_HANA_CONFIG_VERSION(               \
0063                 __clang_major__, __clang_minor__, __clang_patchlevel__)
0064
0065 #elif defined(__GNUC__) // GCC
0066
0067 #   define BOOST_HANA_CONFIG_GCC BOOST_HANA_CONFIG_VERSION(                 \
0068                             __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
0069
0070 #endif
0071
0072 //////////////////////////////////////////////////////////////////////////////
0073 // Check the compiler for general C++14 capabilities
0074 //////////////////////////////////////////////////////////////////////////////
0075 #if (__cplusplus < 201400)
0076 #   if defined(_MSC_VER)
0077 #       if _MSC_VER < 1915
0078 #           pragma message("Warning: Your compiler doesn't provide C++14 or higher capabilities. Try adding the compiler flag '-std=c++14' or '-std=c++1y'.")
0079 #       endif
0080 #   else
0081 #       warning "Your compiler doesn't provide C++14 or higher capabilities. Try adding the compiler flag '-std=c++14' or '-std=c++1y'."
0082 #   endif
0083 #endif
0084
0085 //////////////////////////////////////////////////////////////////////////////
0086 // Caveats and other compiler-dependent options
0087 //////////////////////////////////////////////////////////////////////////////
0088
0089 // `BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA` enables some constructs requiring
0090 // `constexpr` lambdas, which are in the language starting with C++17.
0091 //
0092 // Always disabled for now because Clang only has partial support for them
0093 // (captureless lambdas only).
0094 #if defined(__cplusplus) && __cplusplus > 201402L
0095 #   define BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA constexpr
0096 // #   define BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA
0097 #else
0098 #   define BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA /* nothing */
0099 #endif
0100
0101 // `BOOST_HANA_CONSTEXPR_LAMBDA` expands to `constexpr` if constexpr lambdas
0102 // are supported and to nothing otherwise.
0103 #if defined(BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA)
0104 #   define BOOST_HANA_CONSTEXPR_LAMBDA constexpr
0105 #else
0106 #   define BOOST_HANA_CONSTEXPR_LAMBDA /* nothing */
0107 #endif
0108
0109 // `BOOST_HANA_INLINE_VARIABLE` expands to `inline` when C++17 inline variables
0110 // are supported, and to nothing otherwise. This allows marking global variables
0111 // defined in a header as `inline` to avoid potential ODR violations.
0112 #if defined(__cplusplus) && __cplusplus > 201402L
0113 #   define BOOST_HANA_INLINE_VARIABLE inline
0114 #else
0115 #   define BOOST_HANA_INLINE_VARIABLE /* nothing */
0116 #endif
0117
0118 //////////////////////////////////////////////////////////////////////////////
0119 // Library features and options that can be tweaked by users
0120 //////////////////////////////////////////////////////////////////////////////
0121
0122 #if defined(BOOST_HANA_DOXYGEN_INVOKED) || \
0123     (defined(NDEBUG) && !defined(BOOST_HANA_CONFIG_DISABLE_ASSERTIONS))
0124     //! @ingroup group-config
0125     //! Disables the `BOOST_HANA_*_ASSERT` macro & friends.
0126     //!
0127     //! When this macro is defined, the `BOOST_HANA_*_ASSERT` macro & friends
0128     //! are disabled, i.e. they expand to nothing.
0129     //!
0130     //! This macro is defined automatically when `NDEBUG` is defined. It can
0131     //! also be defined by users before including this header or defined on
0132     //! the command line.
0133 #   define BOOST_HANA_CONFIG_DISABLE_ASSERTIONS
0134 #endif
0135
0136 #if defined(BOOST_HANA_DOXYGEN_INVOKED)
0137     //! @ingroup group-config
0138     //! Disables concept checks in interface methods.
0139     //!
0140     //! When this macro is not defined (the default), tag-dispatched methods
0141     //! will make sure the arguments they are passed are models of the proper
0142     //! concept(s). This can be very helpful in catching programming errors,
0143     //! but it is also slightly less compile-time efficient. You should
0144     //! probably always leave the checks enabled (and hence never define this
0145     //! macro), except perhaps in translation units that are compiled very
0146     //! often but whose code using Hana is modified very rarely.
0147 #   define BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
0148 #endif
0149
0150 #if defined(BOOST_HANA_DOXYGEN_INVOKED)
0151     //! @ingroup group-config
0152     //! Enables usage of the "string literal operator template" GNU extension.
0153     //!
0154     //! That operator is not part of the language yet, but it is supported by
0155     //! both Clang and GCC. This operator allows Hana to provide the nice `_s`
0156     //! user-defined literal for creating compile-time strings.
0157     //!
0158     //! When this macro is not defined, the GNU extension will be not used
0159     //! by Hana. Because this is a non-standard extension, the macro is not
0160     //! defined by default.
0161 #   define BOOST_HANA_CONFIG_ENABLE_STRING_UDL
0162 #endif
0163
0164 #if defined(BOOST_HANA_DOXYGEN_INVOKED)
0165     //! @ingroup group-config
0166     //! Enables additional assertions and sanity checks to be done by Hana.
0167     //!
0168     //! When this macro is defined (it is __not defined__ by default),
0169     //! additional sanity checks may be done by Hana. These checks may
0170     //! be costly to perform, either in terms of compilation time or in
0171     //! terms of execution time. These checks may help debugging an
0172     //! application during its initial development, but they should not
0173     //! be enabled as part of the normal configuration.
0174 #   define BOOST_HANA_CONFIG_ENABLE_DEBUG_MODE
0175 #endif
0176
0177 #endif // !BOOST_HANA_CONFIG_HPP