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+[/
+ Boost.Config
+
+ Copyright (c) 2001 Beman Dawes
+ Copyright (c) 2001 Vesa Karvonen
+ Copyright (c) 2001 John Maddock
+
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+]
+
+
+
+[section Boost Macro Reference]
+
+[#config_defects]
+
+[section Macros that describe C++03 defects]
+
+The following macros all describe features that are required by the C++03 standard,
+if one of the following macros is defined, then it represents a defect in the
+compiler's conformance with the 2003 standard.
+
+
+[table
+[[Macro ][Section ][ Description ]]
+
+
+[[`BOOST_BCB_PARTIAL_SPECIALIZATION_BUG`][Compiler][
+The compiler exhibits certain partial specialisation bug - probably Borland
+C++ Builder specific.
+]]
+[[`BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL`][Compiler][
+Argument dependent lookup fails if there is a using declaration for the
+symbol being looked up in the current scope. For example, using
+`boost::get_pointer`; prevents ADL from finding overloads of `get_pointer`
+in namespaces nested inside boost (but not elsewhere). Probably
+Borland specific.
+]]
+[[`BOOST_NO_ADL_BARRIER`][Compiler][
+The compiler locates and searches namespaces that it should /*not*/ in fact
+search when performing argument dependent lookup.
+]]
+[[`BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP`][Compiler][
+Compiler does not implement argument-dependent lookup (also named
+Koenig lookup); see std::3.4.2 \[basic.koenig.lookup\]
+]]
+[[`BOOST_NO_AUTO_PTR`][Standard library][
+If the compiler / library supplies non-standard or broken `std::auto_ptr`.
+]]
+[[`BOOST_NO_COMPLETE_VALUE_INITIALIZATION`][Compiler][
+Compiler has not completely implemented value-initialization.
+See also [@../../../utility/value_init.htm#compiler_issues The Utility\/Value Init docs]
+]]
+[[`BOOST_NO_CTYPE_FUNCTIONS`][Platform][
+The Platform does not provide functions for the character-classifying
+operations `<ctype.h>` and `<cctype>`, only macros.
+]]
+[[`BOOST_NO_CV_SPECIALIZATIONS`][Compiler][
+If template specialisations for cv-qualified types conflict with a
+specialisation for a cv-unqualififed type.
+]]
+[[`BOOST_NO_CV_VOID_SPECIALIZATIONS`][Compiler][
+If template specialisations for cv-void types conflict with a specialisation
+for void.
+]]
+[[`BOOST_NO_CWCHAR`][Platform][
+The Platform does not provide `<wchar.h>` and `<cwchar>`.
+]]
+[[`BOOST_NO_CWCTYPE`][Platform][
+The Platform does not provide `<wctype.h>` and `<cwctype>`.
+]]
+[[`BOOST_NO_FENV_H`][Platform, Standard library][
+The C standard library doesn't provide `<fenv.h>`. [@../../../../boost/detail/fenv.hpp
+`<boost/detail/fenv.hpp>`] should be included instead of `<fenv.h>` for maximum
+portability on platforms which do provide `<fenv.h>`.
+]]
+[[`BOOST_NO_DEPENDENT_NESTED_DERIVATIONS`][Compiler][
+The compiler fails to compile a nested class that has a dependent base class:
+``
+template<typename T>
+struct foo : {
+ template<typename U>
+ struct bar : public U {};
+``
+};
+]]
+[[`BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS`][Compiler][
+Template value parameters cannot have a dependent type, for example:
+``
+template<class T, typename T::type value>
+class X { ... };
+``
+]]
+[[`BOOST_NO_EXCEPTION_STD_NAMESPACE`][Standard Library][
+The standard library does not put some or all of the contents of
+`<exception>` in namespace std.
+]]
+[[`BOOST_NO_EXCEPTIONS`][Compiler][
+The compiler does not support exception handling (this setting is typically
+required by many C++ compilers for embedded platforms). Note that there is
+no requirement for boost libraries to honor this configuration setting -
+indeed doing so may be impossible in some cases. Those libraries that do
+honor this will typically abort if a critical error occurs - you have been
+warned!
+]]
+[[`BOOST_NO_FUNCTION_TEMPLATE_ORDERING`][Compiler][
+The compiler does not perform function template ordering or its function
+template ordering is incorrect.
+``
+// #1
+template<class T> void f(T);
+
+// #2
+template<class T,class U> void f(T(*)(U));
+
+void bar(int);
+
+f(&bar); // should choose #2.
+``
+]]
+[[`BOOST_NO_INCLASS_MEMBER_INITIALIZATION`][Compiler][
+Compiler violates std::9.4.2/4.
+]]
+[[`BOOST_NO_INTRINSIC_WCHAR_T`][Compiler][
+The C++ implementation does not provide `wchar_t`, or it is really a synonym
+for another integral type. Use this symbol to decide whether it is appropriate
+to explicitly specialize a template on `wchar_t` if there is already a
+specialization for other integer types.
+]]
+[[`BOOST_NO_IOSFWD`][std lib][
+The standard library lacks `<iosfwd>`.
+]]
+[[`BOOST_NO_IOSTREAM`][std lib][
+The standard library lacks `<iostream>`, `<istream>` or `<ostream>`.
+]]
+[[`BOOST_NO_IS_ABSTRACT`][Compiler][
+The C++ compiler does not support SFINAE with abstract types, this is covered
+by __CORE_LANGUAGE_DR337__, but is not part of the current standard. Fortunately
+most compilers that support SFINAE also support this DR. See also BOOST_NO_SFINAE and BOOST_NO_SFINAE_EXPR
+]]
+[[`BOOST_NO_LIMITS`][Standard library][
+The C++ implementation does not provide the `<limits>` header. Never check for
+this symbol in library code; always include `<boost/limits.hpp>`, which
+guarantees to provide `std::numeric_limits`.
+]]
+[[`BOOST_NO_CXX11_NUMERIC_LIMITS`][Standard library][
+C++11 additions to `std::numeric_limits` are not available for use.
+`static function numeric_limits<T>::lowest()` the lowest finite value representable by the numeric type.
+`static int const max_digits10` the number of decimal digits that are required to make sure that two distinct values of the type have distinct decimal representations.
+`template<> class numeric_limits<char16_t>;`, see also `BOOST_NO_CXX11_CHAR16_T`,
+`template<> class numeric_limits<char32_t>;` see also `BOOST_NO_CXX11_CHAR32_T`.
+Replaces BOOST_NO_NUMERIC_LIMITS_LOWEST.
+]]
+[[`BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS`][Standard library][
+Constants such as `numeric_limits<T>::is_signed` are not available for use
+at compile-time.
+]]
+[[`BOOST_NO_LONG_LONG_NUMERIC_LIMITS`][Standard library][
+There is no specialization for `numeric_limits<long long>` and
+`numeric_limits<unsigned long long>`. `<boost/limits.hpp>` will then add these
+specializations as a standard library "fix" only if the compiler supports the
+`long long` datatype.
+]]
+[[`BOOST_NO_MEMBER_FUNCTION_SPECIALIZATIONS`][Compiler][
+The compiler does not support the specialization of individual member
+functions of template classes.
+]]
+[[`BOOST_NO_MEMBER_TEMPLATE_KEYWORD`][Compiler][
+If the compiler supports member templates, but not the template keyword
+when accessing member template classes.
+]]
+[[`BOOST_NO_MEMBER_TEMPLATE_FRIENDS`][Compiler][
+Member template friend syntax (`template<class P> friend class frd;`)
+described in the C++ Standard, 14.5.3, not supported.
+]]
+[[`BOOST_NO_MEMBER_TEMPLATES`][Compiler][
+Member template functions not fully supported.
+]]
+[[`BOOST_NO_MS_INT64_NUMERIC_LIMITS`][Standard library][
+There is no specialization for `numeric_limits<__int64>` and
+`numeric_limits<unsigned __int64>`. `<boost/limits.hpp>` will then add these
+specializations as a standard library "fix", only if the compiler supports
+the `__int64` datatype.
+]]
+[[`BOOST_NO_NESTED_FRIENDSHIP`][Compiler][
+Compiler doesn't allow a nested class to access private members of its
+containing class. Probably Borland/CodeGear specific.
+]]
+[[`BOOST_NO_OPERATORS_IN_NAMESPACE`][Compiler][
+Compiler requires inherited operator friend functions to be defined at
+namespace scope, then using'ed to boost. Probably GCC specific. See
+[@../../../../boost/operators.hpp `<boost/operators.hpp>`] for example.
+]]
+[[`BOOST_NO_PARTIAL_SPECIALIZATION_IMPLICIT_DEFAULT_ARGS`][Compiler][
+The compiler does not correctly handle partial specializations
+which depend upon default arguments in the primary template.
+]]
+[[`BOOST_NO_POINTER_TO_MEMBER_CONST`][Compiler][
+The compiler does not correctly handle pointers to const member functions,
+preventing use of these in overloaded function templates. See
+[@../../../../boost/functional.hpp `<boost/functional.hpp>`] for example.
+]]
+[[`BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS`][Compiler][
+Pointers to members don't work when used as template parameters.
+]]
+[[`BOOST_NO_PRIVATE_IN_AGGREGATE`][Compiler][
+The compiler misreads 8.5.1, treating classes as non-aggregate if they
+contain private or protected member functions.
+]]
+[[`BOOST_NO_RESTRICT_REFERENCES`][Compiler][
+Compiler-specific `restrict` keyword can not be applied to references.
+]]
+[[`BOOST_NO_RTTI`][Compiler][
+The compiler may (or may not) have the typeid operator, but RTTI on the dynamic type
+of an object is not supported.
+]]
+[[`BOOST_NO_SFINAE`][Compiler][
+The compiler does not support the "Substitution Failure Is Not An Error"
+meta-programming idiom. This is the lightweight pre-C++11 version of SFINAE.
+]]
+[[`BOOST_NO_SFINAE_EXPR`][Compiler][
+The compiler does not support usage of SFINAE with arbitrary expressions. This is the
+post-C++11 SFINAE, but excludes a few specific corner cases, see also BOOST_NO_CXX11_SFINAE_EXPR.
+]]
+[[`BOOST_NO_STD_ALLOCATOR`][Standard library][
+The C++ standard library does not provide a standards conforming
+`std::allocator`.
+]]
+[[`BOOST_NO_STD_DISTANCE`][Standard library][
+The platform does not have a conforming version of `std::distance`.
+]]
+[[`BOOST_NO_STD_ITERATOR`][Standard library][
+The C++ implementation fails to provide the `std::iterator` class.
+Note that post C++17, this macro is re-purposed to indicate that std::iterator has been removed or deprecated.
+]]
+[[`BOOST_NO_STD_ITERATOR_TRAITS`][Standard library][
+The compiler does not provide a standard compliant implementation of
+`std::iterator_traits`. Note that the compiler may still have a
+non-standard implementation.
+]]
+[[`BOOST_NO_STD_LOCALE`][Standard library][
+The standard library lacks `std::locale`.
+]]
+[[`BOOST_NO_STD_MESSAGES`][Standard library][
+The standard library lacks a conforming `std::messages` facet.
+]]
+[[`BOOST_NO_STD_MIN_MAX`][Standard library][
+The C++ standard library does not provide the `min()` and `max()` template
+functions that should be in `<algorithm>`.
+]]
+[[`BOOST_NO_STD_OUTPUT_ITERATOR_ASSIGN`][Standard library][
+Defined if the standard library's output iterators are not assignable.
+]]
+[[`BOOST_NO_STD_TYPEINFO`][Standard library][
+The <typeinfo> header declares `type_info` in the global namespace instead of namespace std.
+]]
+[[`BOOST_NO_STD_USE_FACET`][Standard library][
+The standard library lacks a conforming `std::use_facet`.
+]]
+[[`BOOST_NO_STD_WSTREAMBUF`][Standard library][
+The standard library's implementation of `std::basic_streambuf<wchar_t>`
+is either missing, incomplete, or buggy.
+]]
+[[`BOOST_NO_STD_WSTRING`][Standard library][
+The standard library lacks `std::wstring`.
+]]
+[[`BOOST_NO_STDC_NAMESPACE`][Compiler, Platform][
+The contents of C++ standard headers for C library functions
+(the `<c...>` headers) have not been placed in namespace std. This test is
+difficult - some libraries "fake" the std C functions by adding using
+declarations to import them into namespace std, unfortunately they don't
+necessarily catch all of them...
+]]
+[[`BOOST_NO_STRINGSTREAM`][Standard library][
+The C++ implementation does not provide the `<sstream>` header.
+]]
+[[`BOOST_NO_SWPRINTF`][Platform][
+The platform does not have a conforming version of `swprintf`.
+]]
+[[`BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION`][Compiler][
+Class template partial specialization (14.5.4 \[temp.class.spec\]) not
+supported.
+]]
+[[`BOOST_NO_TEMPLATED_IOSTREAMS`][Standard library][
+The standard library does not provide templated iostream classes.
+]]
+[[`BOOST_NO_TEMPLATED_ITERATOR_CONSTRUCTORS`][Standard library][
+The standard library does not provide templated iterator constructors
+for its containers.
+]]
+[[`BOOST_NO_TEMPLATE_TEMPLATES`][Compiler][
+The compiler does not support template template parameters.
+]]
+[[`BOOST_NO_TYPEID`][Compiler][
+The compiler does not support the typeid operator at all.
+]]
+[[`BOOST_NO_TYPENAME_WITH_CTOR`][Compiler][
+The typename keyword cannot be used when creating a temporary of a
+Dependent type.
+]]
+[[`BOOST_NO_UNREACHABLE_RETURN_DETECTION`][Compiler][
+If a return is unreachable, then no return statement should be required,
+however some compilers insist on it, while other issue a bunch of warnings
+if it is in fact present.
+]]
+[[`BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE`][Compiler][
+The compiler will not accept a using declaration that brings a function
+from a typename used as a base class into a derived class if functions of
+the same name are present in the derived class.
+]]
+[[`BOOST_NO_USING_TEMPLATE`][Compiler][
+The compiler will not accept a using declaration that imports a template
+class or function from another namespace. Originally a Borland specific
+problem with imports to/from the global namespace, extended to MSVC6
+which has a specific issue with importing template classes (but not
+functions).
+]]
+[[`BOOST_NO_VOID_RETURNS`][Compiler][
+The compiler does not allow a void function to return the result of calling
+another void function.
+``
+void f() {}
+void g() { return f(); }
+``
+]]
+]
+
+[endsect]
+
+[#config_features]
+
+
+[section Macros that describe optional features]
+
+The following macros describe features that are not required by the C++
+standard. The macro is only defined if the feature is present.
+
+
+[table
+[[Macro ][Section ][Description ]]
+
+[[`BOOST_HAS_BETHREADS`][Platform][
+The platform supports BeOS style threads.
+]]
+[[`BOOST_HAS_CLOCK_GETTIME`][Platform][
+The platform has the POSIX API `clock_gettime`.
+]]
+[[`BOOST_HAS_DIRENT_H`][Platform][
+The platform has the POSIX header `<dirent.h>`.
+]]
+[[`BOOST_HAS_EXPM1`][Platform][
+The platform has the functions `expm1`, `expm1f` and `expm1l` in `<math.h>`
+]]
+[[`BOOST_HAS_FLOAT128`][Compiler][
+The compiler has `__float128` as a native type which is distinct
+from all the regular C++ floating point types.]]
+[[`BOOST_HAS_FTIME`][Platform][
+The platform has the Win32 API type FTIME.
+]]
+[[`BOOST_HAS_GETSYSTEMTIMEASFILETIME`][Platform][
+The platform has the Win32 API GetSystemTimeAsFileTime.
+]]
+[[`BOOST_HAS_GETTIMEOFDAY`][Platform][
+The platform has the POSIX API `gettimeofday`.
+]]
+[[`BOOST_HAS_HASH`][Standard library][
+The C++ implementation provides the (SGI) hash_set and hash_map classes.
+When defined, `BOOST_HASH_SET_HEADER` and `BOOST_HASH_LIST_HEADER` will contain
+the names of the header needed to access hash_set and hash_map;
+`BOOST_STD_EXTENSION_NAMESPACE` will provide the namespace in which the two
+class templates reside.
+]]
+[[`BOOST_HAS_INT128`][Compiler][
+The compiler has `__int128` and `unsigned __int128` as native types which are distinct
+from all the regular C++ integer types.]]
+[[`BOOST_HAS_LOG1P`][Platform][
+The platform has the functions `log1p`, `log1pf` and `log1pl` in `<math.h>`.
+]]
+[[`BOOST_HAS_MACRO_USE_FACET`][Standard library][
+The standard library lacks a conforming `std::use_facet`, but has a macro
+`_USE(loc, Type)` that does the job. This is primarily for the Dinkumware
+std lib.
+]]
+[[`BOOST_HAS_MS_INT64`][Compiler][
+The compiler supports the `__int64` data type.
+]]
+[[`BOOST_HAS_NANOSLEEP`][Platform][
+The platform has the POSIX API nanosleep.
+]]
+[[`BOOST_HAS_NL_TYPES_H`][Platform][
+The platform has an `<nl_types.h>`.
+]]
+[[`BOOST_HAS_NRVO`][Compiler][
+Indicated that the compiler supports the named return value optimization
+(NRVO). Used to select the most efficient implementation for some function.
+See [@../../../../boost/operators.hpp `<boost/operators.hpp>`] for example.
+]]
+[[`BOOST_HAS_PARTIAL_STD_ALLOCATOR`][Standard Library][
+The standard library has a partially conforming `std::allocator` class, but
+without any of the member templates.
+]]
+[[`BOOST_HAS_PRAGMA_ONCE`][Compiler][
+The compiler recognizes the `#pragma once` directive which tells that the
+containing header should be included only once while preprocessing the
+current translation unit. The pragma may improve compile times of large projects
+with some compilers.
+]]
+[[`BOOST_HAS_PRAGMA_DETECT_MISMATCH`][Compiler][
+The compiler recognizes the `#pragma detect_mismatch("name", "value")` directive which tells that the
+link stage should be terminated with error if values for provided `"name"` missmatch.
+This pragma may be a help in preventing ODR violations and ensuring that different modules
+are compiled with same flags.
+]]
+
+[[`BOOST_HAS_PTHREAD_DELAY_NP`][Platform][
+The platform has the POSIX API `pthread_delay_np`.
+]]
+[[`BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE`][Platform][
+The platform has the POSIX API `pthread_mutexattr_settype`.
+]]
+[[`BOOST_HAS_PTHREAD_YIELD`][Platform][
+The platform has the POSIX API `pthread_yield`.
+]]
+[[`BOOST_HAS_PTHREADS`][Platform][
+The platform support POSIX style threads.
+]]
+[[`BOOST_HAS_SCHED_YIELD`][Platform][
+The platform has the POSIX API `sched_yield`.
+]]
+[[`BOOST_HAS_SGI_TYPE_TRAITS`][Compiler, Standard library][
+The compiler has native support for SGI style type traits.
+]]
+[[`BOOST_HAS_STDINT_H`][Platform][
+The platform has a `<stdint.h>`
+]]
+[[`BOOST_HAS_SLIST`][Standard library][
+The C++ implementation provides the (SGI) slist class. When defined,
+`BOOST_SLIST_HEADER` will contain the name of the header needed to access
+`slist` and `BOOST_STD_EXTENSION_NAMESPACE` will provide the namespace in
+which `slist` resides.
+]]
+[[`BOOST_HAS_STLP_USE_FACET`][Standard library][
+The standard library lacks a conforming `std::use_facet`, but has a workaround
+class-version that does the job. This is primarily for the STLport std lib.
+]]
+[[`BOOST_HAS_TR1_ARRAY`][Standard library][
+The library has a TR1 conforming version of `<array>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_ARRAY.
+]]
+[[`BOOST_HAS_TR1_COMPLEX_OVERLOADS`][Standard library][
+The library has a version of `<complex>` that supports passing scalars to the
+complex number algorithms.
+]]
+[[`BOOST_HAS_TR1_COMPLEX_INVERSE_TRIG`][Standard library][
+The library has a version of `<complex>` that includes the new inverse trig
+functions from TR1.
+]]
+[[`BOOST_HAS_TR1_REFERENCE_WRAPPER`][Standard library][
+The library has TR1 conforming reference wrappers in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_RESULT_OF`][Standard library][
+The library has a TR1 conforming result_of template in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_MEM_FN`][Standard library][
+The library has a TR1 conforming mem_fn function template in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_BIND`][Standard library][
+The library has a TR1 conforming bind function template in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_FUNCTION`][Standard library][
+The library has a TR1 conforming function class template in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_HASH`][Standard library][
+The library has a TR1 conforming hash function template in `<functional>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_FUNCTIONAL.
+]]
+[[`BOOST_HAS_TR1_SHARED_PTR`][Standard library][
+The library has a TR1 conforming `shared_ptr` class template in `<memory>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_SMART_PTR.
+]]
+[[`BOOST_HAS_TR1_RANDOM`][Standard library][
+The library has a TR1 conforming version of `<random>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_RANDOM.
+]]
+[[`BOOST_HAS_TR1_REGEX`][Standard library][
+The library has a TR1 conforming version of `<regex>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_REGEX.
+]]
+[[`BOOST_HAS_TR1_TUPLE`][Standard library][
+The library has a TR1 conforming version of `<tuple>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_TUPLE.
+]]
+[[`BOOST_HAS_TR1_TYPE_TRAITS`][Standard library][
+The library has a TR1 conforming version of `<type_traits>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_TYPE_TRAITS.
+]]
+[[`BOOST_HAS_TR1_UTILITY`][Standard library][
+The library has the TR1 additions to `<utility>` (tuple interface to `std::pair`). This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_TUPLE.
+]]
+[[`BOOST_HAS_TR1_UNORDERED_MAP`][Standard library][
+The library has a TR1 conforming version of `<unordered_map>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_UNORDERED_MAP.
+]]
+[[`BOOST_HAS_TR1_UNORDERED_SET`][Standard library][
+The library has a TR1 conforming version of `<unordered_set>`. This macro is only guaranteed
+to be defined after including one of the headers from Boost.TR1. Further this macro
+is now deprecated in favour of BOOST_NO_CXX11_HDR_UNORDERED_SET.
+]]
+[[`BOOST_HAS_TR1`][Standard library][
+Implies all the other `BOOST_HAS_TR1_*` macros should be set.
+]]
+[[`BOOST_HAS_THREADS`][Platform, Compiler][
+Defined if the compiler, in its current translation mode, supports multiple
+threads of execution.
+]]
+[[`BOOST_HAS_TWO_ARG_USE_FACET`][Standard library][
+The standard library lacks a conforming std::use_facet, but has a two
+argument version that does the job. This is primarily for the Rogue Wave
+std lib.
+]]
+[[`BOOST_HAS_UNISTD_H`][Platform][
+The Platform provides `<unistd.h>`.
+]]
+[[`BOOST_HAS_WINTHREADS`][Platform][
+The platform supports MS Windows style threads.
+]]
+[[`BOOST_MSVC_STD_ITERATOR`][Standard library][
+Microsoft's broken version of `std::iterator` is being used. This implies that
+`std::iterator` takes no more than two template parameters.
+]]
+[[`BOOST_MSVC6_MEMBER_TEMPLATES`][Compiler][
+Microsoft Visual C++ 6.0 has enough member template idiosyncrasies
+(being polite) that `BOOST_NO_MEMBER_TEMPLATES` is defined for this compiler.
+`BOOST_MSVC6_MEMBER_TEMPLATES` is defined to allow compiler specific workarounds.
+This macro gets defined automatically if `BOOST_NO_MEMBER_TEMPLATES` is not
+defined - in other words this is treated as a strict subset of the features
+required by the standard.
+]]
+[[`BOOST_HAS_STDINT_H`][Platform][
+There are no 1998 C++ Standard headers `<stdint.h>` or `<cstdint>`, although the
+1999 C Standard does include `<stdint.h>`. If `<stdint.h>` is present,
+`<boost/stdint.h>` can make good use of it, so a flag is supplied (signalling
+presence; thus the default is not present, conforming to the current C++
+standard).
+]]
+]
+
+[endsect]
+
+[section Macros that describe possible C++ future features]
+
+The following macros describe features that may be included in some future
+ISO C++ standard, but have not yet been approved for inclusion in the language.
+
+
+[table
+[[Macro ][Description ]]
+
+[[`BOOST_HAS_CONCEPTS`][
+The compiler supports concepts.
+]]
+]
+
+[endsect]
+
+[section Macros that describe C++11 features not supported]
+
+The following macros describe features in the 2011 ISO C++ standard, formerly known as C++0x,
+that are not yet supported by a particular compiler or library.
+
+[table
+[[Macro ][Description ]]
+
+[[`BOOST_NO_CXX11_ADDRESSOF`][The standard library header <memory> has no working std::addressof.]]
+[[`BOOST_NO_CXX11_ALIGNAS`][The compiler does not support the `alignas` keyword.]]
+[[`BOOST_NO_CXX11_ALLOCATOR`][The standard library does not provide a C++11 version of `std::allocator` in <memory>.]]
+[[`BOOST_NO_CXX11_ATOMIC_SMART_PTR`][The standard library <memory> does not support atomic smart pointer operations.]]
+[[`BOOST_NO_CXX11_AUTO_DECLARATIONS`][The compiler does not support
+type deduction for variables declared with the `auto` keyword (`auto var = ...;`).
+]]
+[[`BOOST_NO_CXX11_AUTO_MULTIDECLARATIONS`][The compiler does not support
+type deduction for multiple variables declared with the `auto` keyword (`auto var = ..., *ptr = ...;`).
+]]
+[[`BOOST_NO_CXX11_CHAR16_T`][The compiler does not support
+type `char16_t`.
+]]
+[[`BOOST_NO_CXX11_CHAR32_T`][The compiler does not support
+type `char32_t`.
+]]
+[[`BOOST_NO_CXX11_CONSTEXPR`][The compiler does not support
+`constexpr`.
+]]
+[[`BOOST_NO_CXX11_DECLTYPE`][The compiler does not support
+`decltype`.
+]]
+[[`BOOST_NO_CXX11_DECLTYPE_N3276`][The compiler does not support the extension to
+`decltype` described in [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3276.pdf N3276],
+accepted in Madrid, March 2011.
+]]
+[[`BOOST_NO_CXX11_DELETED_FUNCTIONS`][The compiler does not support
+deleted (`= delete`) functions.
+]]
+[[`BOOST_NO_CXX11_DEFAULTED_FUNCTIONS`][The compiler does not support
+defaulted (`= default`) functions.
+]]
+[[`BOOST_NO_CXX11_DEFAULTED_MOVES`][The compiler does not support
+defaulted move constructor or assignment. Other defaulted functions may still be supported.
+]]
+[[`BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS`][The compiler does not support
+explicit conversion operators (`explicit operator T()`).
+]]
+[[`BOOST_NO_CXX11_EXTERN_TEMPLATE`][The compiler does not support
+explicit instantiation forward declarations for templates (`extern template ...`).
+]]
+[[`BOOST_NO_CXX11_FINAL`][The compiler does not support the C++ class-virt-specifier final.
+]]
+[[`BOOST_NO_CXX11_FIXED_LENGTH_VARIADIC_TEMPLATE_EXPANSION_PACKS`][The compiler does not support
+expanding a variadic template parameter pack into a template containing one or more
+fixed arguments]]
+[[`BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS`][The compiler does not support
+default template arguments for function templates.
+]]
+[[`BOOST_NO_CXX11_HDR_ATOMIC`][The standard library does not provide header <atomic>.]]
+[[`BOOST_NO_CXX11_HDR_ARRAY`][The standard library does not provide header <array>.]]
+[[`BOOST_NO_CXX11_HDR_CHRONO`][The standard library does not provide header <chrono>.]]
+[[`BOOST_NO_CXX11_HDR_CODECVT`][The standard library does not provide header <codecvt>.]]
+[[`BOOST_NO_CXX11_HDR_CONDITION_VARIABLE`][The standard library does not provide header <condition_variable>.]]
+[[`BOOST_NO_CXX11_HDR_FORWARD_LIST`][The standard library does not provide header <forward_list>.]]
+[[`BOOST_NO_CXX11_HDR_FUNCTIONAL`][The standard library does not provide a C++11 compatible version of <functional>.]]
+[[`BOOST_NO_CXX11_HDR_FUTURE`][The standard library does not provide header <future>.]]
+[[`BOOST_NO_CXX11_HDR_INITIALIZER_LIST`][The standard library does not provide header <initializer_list>.]]
+[[`BOOST_NO_CXX11_HDR_MUTEX`][The standard library does not provide header <mutex>.]]
+[[`BOOST_NO_CXX11_HDR_RANDOM`][The standard library does not provide header <random>.]]
+[[`BOOST_NO_CXX11_HDR_RATIO`][The standard library does not provide header <ratio>.]]
+[[`BOOST_NO_CXX11_HDR_REGEX`][The standard library does not provide header <regex>.]]
+[[`BOOST_NO_CXX11_HDR_SYSTEM_ERROR`][The standard library does not provide header <system_error>.]]
+[[`BOOST_NO_CXX11_HDR_THREAD`][The standard library does not provide header <thread>.]]
+[[`BOOST_NO_CXX11_HDR_TUPLE`][The standard library does not provide header <tuple>.]]
+[[`BOOST_NO_CXX11_HDR_TYPEINDEX`][The standard library does not provide header <typeindex>.]]
+[[`BOOST_NO_CXX11_HDR_TYPE_TRAITS`][The standard library does not provide header <type_traits>.]]
+[[`BOOST_NO_CXX11_HDR_UNORDERED_MAP`][The standard library does not provide header <unordered_map>.]]
+[[`BOOST_NO_CXX11_HDR_UNORDERED_SET`][The standard library does not provide header <unordered_set>.]]
+
+[[`BOOST_NO_CXX11_INLINE_NAMESPACES`][The compiler does not support inline namespaces.]]
+[[`BOOST_NO_CXX11_LAMBDAS`][The compiler does not support Lambdas.
+]]
+[[`BOOST_NO_CXX11_LOCAL_CLASS_TEMPLATE_PARAMETERS`][The compiler does not allow to
+pass local classes as template parameters (this macro intentionally does not
+control passing of unnamed types as template parameters, see also
+[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm N2657]).
+]]
+[[`BOOST_NO_CXX11_NON_PUBLIC_DEFAULTED_FUNCTIONS`][The compiler does not support
+defaulted (`= default`) functions in access control sections other than `public`. Public defaulted
+functions may still be supported, as indicated by `BOOST_NO_CXX11_DEFAULTED_FUNCTIONS`. Some
+compilers implementing an early draft of the C++11 standard (in particular, incorporating
+[@http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#906 DR906]) are susceptible to this problem.
+]]
+[[`BOOST_NO_CXX11_NOEXCEPT`][The compiler does not support `noexcept`.
+]]
+[[`BOOST_NO_CXX11_NULLPTR`][The compiler does not support `nullptr`.
+]]
+[[`BOOST_NO_CXX11_NUMERIC_LIMITS`][The standard library `<limits>` header does
+not support the C++11 version of `numeric_limits`.
+]]
+[[`BOOST_NO_CXX11_POINTER_TRAITS`][The standard library does not provide a
+C++11 version of `std::pointer_traits` in <memory>.]]
+[[`BOOST_NO_CXX11_RANGE_BASED_FOR`][The compiler does not support
+range-based for statements.
+]]
+[[`BOOST_NO_CXX11_RAW_LITERALS`][The compiler does not support
+raw string literals.
+]]
+[[`BOOST_NO_CXX11_REF_QUALIFIERS`][The compiler does not support
+ref-qualifiers on member functions as described in
+[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2439.htm N2439].
+]]
+[[`BOOST_NO_CXX11_RVALUE_REFERENCES`][The compiler does not support
+r-value references.
+]]
+[[`BOOST_NO_CXX11_SCOPED_ENUMS`][The compiler does not support
+scoped enumerations (`enum class`).
+]]
+[[`BOOST_NO_CXX11_SFINAE_EXPR`][The compiler does not support
+usage of C++11 SFINAE with arbitrary expressions. Use this macro only if you
+are using all of the features of SFINAE including substitution-failure-on-private-member-access.
+Otherwise use BOOST_NO_SFINAE_EXPR or BOOST_NO_SFINAE which get defined for fewer compilers.
+]]
+[[`BOOST_NO_CXX11_SMART_PTR`][The standard library header <memory> has no shared_ptr and unique_ptr.]]
+[[`BOOST_NO_CXX11_STATIC_ASSERT`][The compiler does not support
+`static_assert`.
+]]
+[[`BOOST_NO_CXX11_STD_ALIGN`][The standard library header <memory> has no working std::align.]]
+[[`BOOST_NO_CXX11_STD_UNORDERED`][The standard library does not support
+<unordered_map> and <unordered_set>.
+]]
+[[`BOOST_NO_CXX11_TEMPLATE_ALIASES`][The compiler does not support template aliases.
+]]
+[[`BOOST_NO_CXX11_THREAD_LOCAL`][The compiler does not support the `thread_local` storage specifier.
+]]
+[[`BOOST_NO_CXX11_TRAILING_RESULT_TYPES`][The compiler does not support the new function result type
+specification syntax (e.g. `auto foo(T) -> T;`).]]
+[[`BOOST_NO_CXX11_UNICODE_LITERALS`][The compiler does not support
+Unicode (`u8`, `u`, `U`) literals.
+]]
+[[`BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX`][The compiler does not support
+the [@http://en.wikipedia.org/wiki/C%2B%2B0x#Uniform_initialization C++11 Unified Initialization Syntax].
+]]
+[[`BOOST_NO_CXX11_USER_DEFINED_LITERALS`][The compiler does not support user defined literals.
+]]
+[[`BOOST_NO_CXX11_VARIADIC_TEMPLATES`][The compiler does not support
+variadic templates.
+]]
+[[`BOOST_NO_CXX11_VARIADIC_MACROS`][The compiler does not support
+variadic macros.
+]]
+[[`BOOST_NO_LONG_LONG`][The compiler does not support `long long`.
+]]
+]
+
+[endsect]
+
+[#config_11_for_03]
+
+[section Macros that allow use of C++11 features with C++03 compilers]
+
+The following macros allow use of C++11 features even with compilers that do not yet
+provide compliant C++11 support.
+
+[table
+[[Macro ][ Description ]]
+
+[[`BOOST_ALIGNMENT(X)`, `BOOST_NO_ALIGNMENT`][
+Some compilers don't support the `alignas` keyword but provide other means to specify alignment
+(usually, through compiler-specific attributes). The macro `BOOST_ALIGNMENT(X)` will expand to the `alignas(X)`
+keyword if the compiler supports it or to some compiler-specific attribute to achieve the specified alignment.
+If no such compiler-specific attribute is known then `BOOST_ALIGNMENT(X)` will expand to nothing and
+`BOOST_NO_ALIGNMENT` will be defined. Unlike native `alignas`, `X` must always be a compile-time integer constant.
+The macro can be used to specify alignment of types and data:
+``
+ struct BOOST_ALIGNMENT(16) my_data
+ {
+ char c[16];
+ };
+ BOOST_ALIGNMENT(8) int arr[32];
+``
+]]
+[[`BOOST_CONSTEXPR`][
+Some compilers don't support the use of `constexpr`. This macro expands to nothing on those compilers, and `constexpr`
+elsewhere. For example, when defining a constexpr function or constructor replace:
+``
+ constexpr tuple();
+``
+with:
+``
+ BOOST_CONSTEXPR tuple();
+``
+]]
+[[`BOOST_CONSTEXPR_OR_CONST`][
+Some compilers don't support the use of `constexpr`. This macro expands to `const` on those compilers, and `constexpr`
+elsewhere. For example, when defining const expr variables replace:
+``
+ static constexpr UIntType xor_mask = a;
+``
+with:
+``
+ static BOOST_CONSTEXPR_OR_CONST UIntType xor_mask = a;
+``
+]]
+[[`BOOST_STATIC_CONSTEXPR`][
+This is a shortcut for `static BOOST_CONSTEXPR_OR_CONST`. For example, when defining const expr variables replace:
+``
+ static constexpr UIntType xor_mask = a;
+``
+with:
+``
+ BOOST_STATIC_CONSTEXPR UIntType xor_mask = a;
+``
+]]
+[[`BOOST_DEFAULTED_FUNCTION(fun, body)`][
+This macro is intended to be used within a class definition in order to declare a default implementation of function `fun`.
+For the compilers that do not support C++11 defaulted functions the macro will expand into an inline function definition
+with the `body` implementation. For example:
+``
+ struct my_struct
+ {
+ BOOST_DEFAULTED_FUNCTION(my_struct(), {})
+ };
+``
+is equivalent to:
+``
+ struct my_struct
+ {
+ my_struct() = default;
+ };
+``
+or:
+``
+ struct my_struct
+ {
+ my_struct() {}
+ };
+``
+]]
+[[`BOOST_DELETED_FUNCTION(fun)`][
+This macro is intended to be used within a class definition in order to declare a deleted function `fun`.
+For the compilers that do not support C++11 deleted functions the macro will expand into a private function
+declaration with no definition. Since the macro may change the access mode, it is recommended to use this macro
+at the end of the class definition. For example:
+``
+ struct noncopyable
+ {
+ BOOST_DELETED_FUNCTION(noncopyable(noncopyable const&))
+ BOOST_DELETED_FUNCTION(noncopyable& operator= (noncopyable const&))
+ };
+``
+is equivalent to:
+``
+ struct noncopyable
+ {
+ noncopyable(noncopyable const&) = delete;
+ noncopyable& operator= (noncopyable const&) = delete;
+ };
+``
+or:
+``
+ struct noncopyable
+ {
+ private:
+ noncopyable(noncopyable const&);
+ noncopyable& operator= (noncopyable const&);
+ };
+``
+]]
+[[
+``
+ BOOST_NOEXCEPT
+ BOOST_NOEXCEPT_OR_NOTHROW
+ BOOST_NOEXCEPT_IF(Predicate)
+ BOOST_NOEXCEPT_EXPR(Expression)
+``
+][
+If `BOOST_NO_CXX11_NOEXCEPT` is defined (i.e. C++03 compliant compilers) these macros are defined as:
+[:
+``
+ #define BOOST_NOEXCEPT
+ #define BOOST_NOEXCEPT_OR_NOTHROW throw()
+ #define BOOST_NOEXCEPT_IF(Predicate)
+ #define BOOST_NOEXCEPT_EXPR(Expression) false
+``
+]
+If `BOOST_NO_CXX11_NOEXCEPT` is not defined (i.e. C++11 compliant compilers) they are defined as:
+[:
+``
+ #define BOOST_NOEXCEPT noexcept
+ #define BOOST_NOEXCEPT_OR_NOTHROW noexcept
+ #define BOOST_NOEXCEPT_IF(Predicate) noexcept((Predicate))
+ #define BOOST_NOEXCEPT_EXPR(Expression) noexcept((Expression))
+``
+]
+]]
+[[`BOOST_MSVC_ENABLE_2012_NOV_CTP`][
+For Microsoft Visual C++ 2012, enable the C++11 features supplied by the
+November 2012 Community Technology Preview. These features are not automatically
+enabled because the CTP is non-supported alpha code that is not recommended
+for production use. This macro must be defined before including any Boost headers,
+and must be defined for all translation units in the program, including Boost library builds.
+This macro will no longer have any effect once an official Microsoft
+release supports the CTP features.
+]]
+]
+
+[endsect]
+
+[section Macros that describe C++14 features not supported]
+
+The following macros describe features in the 2014 ISO C++ standard, formerly known as C++0y,
+that are not yet supported by a particular compiler or library.
+
+[table
+[[Macro ][Description ]]
+[[`BOOST_NO_CXX14_AGGREGATE_NSDMI`][The compiler does not support member initializer for aggregates as in the following example:
+[:
+``
+struct Foo
+{
+ int x, y = 42;
+};
+
+Foo foo = { 0 };
+``
+]
+]]
+[[`BOOST_NO_CXX14_BINARY_LITERALS`][The compiler does not binary literals (e.g. `0b1010`).]]
+[[`BOOST_NO_CXX14_CONSTEXPR`][The compiler does not support relaxed `constexpr`.]]
+[[`BOOST_NO_CXX14_DECLTYPE_AUTO`][The compiler does not support `decltype(auto)`.]]
+[[`BOOST_NO_CXX14_DIGIT_SEPARATORS`][The compiler does not support digit separators (e.g. `1'000'000`).]]
+[[`BOOST_NO_CXX14_STD_EXCHANGE`][The compiler does not support `std::exchange()`.]]
+[[`BOOST_NO_CXX14_GENERIC_LAMBDAS`][The compiler does not support generic lambda (e.g. `[](auto v){ }`).]]
+[[`BOOST_NO_CXX14_HDR_SHARED_MUTEX`][The standard library does not provide header <shared_mutex>.]]
+[[`BOOST_NO_CXX14_INITIALIZED_LAMBDA_CAPTURES`][The compiler does not support initialized lambda capture (e.g. `[foo = 42]{ }`).]]
+[[`BOOST_NO_CXX14_RETURN_TYPE_DEDUCTION`][The compiler does not support return type deduction for normal functions (e.g. `auto f() { return val; }`).]]
+[[`BOOST_NO_CXX14_VARIABLE_TEMPLATES`][The compiler does not support variable template (e.g. `template <class T> T kibi = T(1024);`).]]
+]
+
+[endsect]
+
+[#config_14_for_11]
+
+[section Macros that allow use of C++14 features with C++11 or earlier compilers]
+
+The following macros allow use of C++14 features even with compilers that do not yet
+provide compliant C++14 support.
+
+[table
+[[Macro ][ Description ]]
+[[`BOOST_CXX14_CONSTEXPR`][This macro works similar to BOOST_CONSTEXPR, but expands to `constexpr` only if the C++14 "relaxed" `constexpr` is available.]]
+]
+
+[endsect]
+
+[section Macros that describe C++17 features not supported]
+
+The following macros describe features in the 2017 ISO C++ standard, formerly known as C++1z,
+that are not yet supported by a particular compiler or library.
+
+[table
+[[Macro ][Description ]]
+[[`BOOST_NO_CXX17_STD_APPLY`][The compiler does not support `std::apply()`.]]
+[[`BOOST_NO_CXX17_STD_INVOKE`][The compiler does not support `std::invoke()`.]]
+[[`BOOST_NO_CXX17_ITERATOR_TRAITS`][The compiler does not support SFINAE-friendly `std::iterator_traits`.]]
+[[`BOOST_NO_CXX17_IF_CONSTEXPR`][The compiler does not support `if constexpr`.]]
+]
+
+[endsect]
+
+[section Macros that describe features that have been removed from the standard.]
+
+The following macros describe features which were required by one version of the standard, but have been removed by later versions.
+
+[table
+[[Macro ][Description ]]
+[[`BOOST_NO_CXX98_RANDOM_SHUFFLE`][The standard library no longer supports `std::random_shuffle()`. It was deprecated in C++11 and is removed from C++14.]]
+[[`BOOST_NO_AUTO_PTR`][The standard library no longer supports `std::auto_ptr`. It was deprecated in C++11 and is removed from C++14.]]
+[[`BOOST_NO_CXX98_FUNCTION_BASE`][The standard library no longer supports `std::unary_function` and `std::binary_function`. They were deprecated in C++11 and is removed from C++14.]]
+[[`BOOST_NO_CXX98_BINDERS`][The standard library no longer supports `std::bind1st`, `std::bind2nd`, `std::ptr_fun` and `std::mem_fun`. They were deprecated in C++11 and is removed from C++14.]]
+]
+
+[endsect]
+
+[#config_helpers]
+
+[section Boost Helper Macros]
+
+The following macros are either simple helpers, or macros that provide
+workarounds for compiler/standard library defects.
+
+
+[table
+[[Macro ][Description ]]
+
+[[`BOOST_WORKAROUND`][
+This macro is used where a compiler specific workaround is required that is not otherwise
+described by one of the other Boost.Config macros. To use the macro you must first
+``
+#include <boost/config/workaround.hpp>
+``
+usage is then:
+``
+#if BOOST_WORKAROUND(MACRONAME, CONDITION)
+ // workaround code goes here...
+#else
+ // Standard conforming code goes here...
+#endif
+``
+where `MACRONAME` is a macro that usually describes the version number to be tested against, and `CONDITION`
+is a comparison operator followed by a value. For example `BOOST_WORKAROUND(BOOST_INTEL, <= 1010)` would
+evaluate to `1` for Intel C++ 10.1 and earlier.
+
+The macro can also be used with `BOOST_TESTED_AT` if all
+current compiler versions exhibit the issue, but the issue is expected to be fixed at some later point.
+
+For example
+`BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x590))` would normally evaluate to `1` for all values
+of `__BORLANDC__` /unless/ the macro `BOOST_DETECT_OUTDATED_WORKAROUNDS` is defined, in which case evaluates to
+`(__BORLANDC__ <= 0x590)`.
+
+[*Note]: the ultimate source of documentation for this macro is in [@../../../../boost/config/workaround.hpp boost/config/workaround.hpp].
+]]
+[[`BOOST_PREVENT_MACRO_SUBSTITUTION`][
+Sometimes you have a function name with the same name as a C macro, for example "min" and "max"
+member functions, in which case one can prevent the function being expanded as a macro using:
+``
+someclass.min BOOST_PREVENT_MACRO_SUBSTITUTION(arg1, arg2);
+``
+The following also works in most, but not all, contexts:
+``
+(someclass.max)(arg1, arg2);
+``
+]]
+[[`BOOST_DEDUCED_TYPENAME`][
+Some compilers don't support the use of typename for dependent types in deduced
+contexts. This macro expands to nothing on those compilers, and typename
+elsewhere. For example, replace:
+`template <class T> void f(T, typename T::type);`
+with:
+`template <class T> void f(T, BOOST_DEDUCED_TYPENAME T::type);`
+]]
+[[`BOOST_HASH_MAP_HEADER`][
+The header to include to get the SGI `hash_map` class. This macro is only
+available if `BOOST_HAS_HASH` is defined.
+]]
+[[`BOOST_HASH_SET_HEADER`][
+The header to include to get the SGI `hash_set` class. This macro is only
+available if `BOOST_HAS_HASH` is defined.
+]]
+[[`BOOST_SLIST_HEADER`][
+The header to include to get the SGI `slist` class. This macro is only
+available if `BOOST_HAS_SLIST` is defined.
+]]
+[[`BOOST_STD_EXTENSION_NAMESPACE`][
+The namespace used for std library extensions (hashtable classes etc).
+]]
+[[`BOOST_STATIC_CONSTANT(Type, assignment)`][
+On compilers which don't allow in-class initialization of static integral
+constant members, we must use enums as a workaround if we want the constants
+to be available at compile-time. This macro gives us a convenient way to
+declare such constants.
+For example instead of:
+``
+struct foo{
+ static const int value = 2;
+};
+``
+use:
+``
+struct foo{
+ BOOST_STATIC_CONSTANT(int, value = 2);
+};
+``
+]]
+[[`BOOST_UNREACHABLE_RETURN(result)`][
+Normally evaluates to nothing, but evaluates to return x; if the compiler
+requires a return, even when it can never be reached.
+]]
+[[`BOOST_FALLTHROUGH`][
+The BOOST_FALLTHROUGH macro can be used to annotate implicit fall-through
+between switch labels:
+``
+ switch (x) {
+ case 40:
+ case 41:
+ if (truth_is_out_there) {
+ ++x;
+ BOOST_FALLTHROUGH; // Use instead of/along with annotations in
+ // comments.
+ } else {
+ return x;
+ }
+ case 42:
+ ...
+``
+As shown in the example above, the BOOST_FALLTHROUGH macro should be
+followed by a semicolon. It is designed to mimic control-flow statements
+like 'break;', so it can be placed in most places where 'break;' can, but
+only if there are no statements on the execution path between it and the
+next switch label.
+
+When compiled with Clang >3.2 in C++11 mode, the BOOST_FALLTHROUGH macro is
+expanded to `[[clang::fallthrough]]` attribute, which is analysed when
+performing switch labels fall-through diagnostic ('-Wimplicit-fallthrough').
+See clang [@http://clang.llvm.org/docs/LanguageExtensions.html#clang__fallthrough
+documentation on language extensions for details.]
+
+When used with unsupported compilers, the BOOST_FALLTHROUGH macro has no
+effect on diagnostics.
+
+In either case this macro has no effect on runtime behavior and performance
+of code.
+]]
+[[`BOOST_EXPLICIT_TEMPLATE_TYPE(t)`
+
+ `BOOST_EXPLICIT_TEMPLATE_NON_TYPE(t,v)`
+
+ `BOOST_APPEND_EXPLICIT_TEMPLATE_TYPE(t)`
+
+ `BOOST_APPEND_EXPLICIT_TEMPLATE_NON_TYPE(t,v)`][
+Some compilers silently "fold" different function template instantiations if
+some of the template parameters don't appear in the function parameter list.
+For instance:
+``
+ #include <iostream>
+ #include <ostream>
+ #include <typeinfo>
+
+ template <int n>
+ void f() { std::cout << n << ' '; }
+
+ template <typename T>
+ void g() { std::cout << typeid(T).name() << ' '; }
+
+ int main() {
+ f<1>();
+ f<2>();
+
+ g<int>();
+ g<double>();
+ }
+``
+incorrectly outputs [^2 2 double double] on VC++ 6. These macros, to be used
+in the function parameter list, fix the problem without effects on the calling
+syntax. For instance, in the case above write:
+``
+ template <int n>
+ void f(BOOST_EXPLICIT_TEMPLATE_NON_TYPE(int, n)) { ... }
+
+ template <typename T>
+ void g(BOOST_EXPLICIT_TEMPLATE_TYPE(T)) { ... }
+``
+Beware that they can declare (for affected compilers) a dummy defaulted
+parameter, so they
+
+[*a)] should be always invoked [*at the end] of the parameter list
+
+[*b)] can't be used if your function template is multiply declared.
+
+Furthermore, in order to add any needed comma separator, an `APPEND_*` version
+must be used when the macro invocation appears after a normal parameter
+declaration or after the invocation of another macro of this same group.
+]]
+[[`BOOST_USE_FACET(Type, loc)`][
+When the standard library does not have a conforming `std::use_facet` there
+are various workarounds available, but they differ from library to library.
+This macro provides a consistent way to access a locale's facets. For example,
+replace:
+`std::use_facet<Type>(loc);`
+with:
+`BOOST_USE_FACET(Type, loc);`
+Note do not add a `std::` prefix to the front of `BOOST_USE_FACET`.
+]]
+[[`BOOST_HAS_FACET(Type, loc)`][
+When the standard library does not have a comforming `std::has_facet` there
+are various workarounds available, but they differ from library to library.
+This macro provides a consistent way to check a locale's facets. For example,
+replace:
+`std::has_facet<Type>(loc);`
+with:
+`BOOST_HAS_FACET(Type, loc);`
+Note do not add a `std::` prefix to the front of `BOOST_HAS_FACET`.
+]]
+[[`BOOST_NESTED_TEMPLATE`][
+Member templates are supported by some compilers even though they can't use
+the `A::template member<U>` syntax, as a workaround replace:
+`typedef typename A::template rebind<U> binder;`
+with:
+`typedef typename A::BOOST_NESTED_TEMPLATE rebind<U> binder;`
+]]
+[[`BOOST_STRINGIZE(X)`][
+Converts the parameter `X` to a string after macro replacement on `X` has
+been performed.
+]]
+[[`BOOST_JOIN(X,Y)`][
+This piece of macro magic joins the two arguments together, even when one of
+the arguments is itself a macro (see 16.3.1 in C++ standard). This is normally
+used to create a mangled name in combination with a predefined macro such a
+\_\_LINE__.
+]]
+[[`BOOST_RESTRICT`][
+This macro can be used in place of the compiler specific variant of the C99 `restrict` keyword to
+notify the compiler that, for the lifetime of the qualified pointer variable, only it and its
+derivative value will be used to gain access to the object it references. This limits the effect of
+pointer aliasing and helps the optimizers in generating better code. However, i this condition is
+violated, undefined behavior may occurs.
+
+Usage example:
+``
+ void perform_computation( float* BOOST_RESTRICT in, float* BOOST_RESTRICT out )
+ {
+ *out = *in * 0.5f;
+ }
+``
+]]
+[[`BOOST_FORCEINLINE`][
+This macro can be used in place of the `inline` keyword to instruct the compiler
+that the function should always be inlined.
+Overuse of this macro can lead to significant bloat, while good use can increase
+performance in certain cases, such as computation-intensive code built through
+generative programming techniques.
+
+Usage example:
+``
+ template<class T>
+ BOOST_FORCEINLINE T& f(T& t)
+ {
+ return t;
+ }
+``
+
+Note that use of this macro can lead to cryptic error messages with some compilers.
+Consider defining it to `inline` before including the Boost.Config header in order to be
+able to debug errors more easily.
+]]
+[[`BOOST_NOINLINE`][
+This macro can be used in place of the `inline` keyword to instruct the compiler
+that the function should never be inlined. One should typically use this macro
+to mark functions that are unlikely to be called, such as error handling routines.
+
+Usage example:
+``
+ BOOST_NOINLINE void handle_error(const char* descr)
+ {
+ // ...
+ }
+``
+]]
+[[`BOOST_NORETURN`][
+This macro can be used before the function declaration or definition to instruct the compiler
+that the function does not return normally (i.e. with a `return` statement or by leaving
+the function scope, if the function return type is `void`). The macro can be used to mark
+functions that always throw exceptions or terminate the application. Compilers that support
+this markup may use this information to specifically organize the code surrounding calls to
+this function and suppress warnings about missing `return` statements in the functions
+enclosing such calls.
+
+Usage example:
+``
+ BOOST_NORETURN void on_error_occurred(const char* descr)
+ {
+ throw std::runtime_error(descr);
+ }
+``
+
+If the compiler does not support this markup, `BOOST_NORETURN` is defined empty and an
+additional macro `BOOST_NO_NORETURN` is defined.
+]]
+[[`BOOST_LIKELY(X)`
+
+ `BOOST_UNLIKELY(X)`][
+These macros communicate to the compiler that the conditional expression `X` is likely
+or unlikely to yield a positive result. The expression should result in a boolean value.
+The result of the macro is an integer or boolean value equivalent to the result of `X`.
+
+The macros are intended to be used in branching statements. The additional hint they provide
+can be used by the compiler to arrange the compiled code of the branches more effectively.
+
+Usage example:
+``
+ if (BOOST_UNLIKELY(ptr == NULL))
+ handle_error("ptr is NULL");
+``
+]]
+[[`BOOST_ATTRIBUTE_UNUSED`][Expands to `__attribute__((unused))` when this is available -
+can be used to disable compiler warnings relating to unused types or variables.]]
+[[`BOOST_MAY_ALIAS`, `BOOST_NO_MAY_ALIAS`][
+`BOOST_MAY_ALIAS` expands to a type attribute that can be used to mark types that may
+alias other types. Pointers or references to such marked types can be used to access objects
+of other types. If the compiler supports this feature `BOOST_NO_MAY_ALIAS` is not defined.
+Otherwise `BOOST_MAY_ALIAS` expands to nothing and `BOOST_NO_MAY_ALIAS` is defined.
+
+Usage example:
+``
+ struct BOOST_MAY_ALIAS aliasing_struct;
+ typedef unsigned int BOOST_MAY_ALIAS aliasing_uint;
+``
+]]
+[[`BOOST_PRAGMA_MESSAGE(M)`][Defined in header `<boost/config/pragma_message.hpp>`,
+this macro expands to the equivalent of `#pragma message(M)`. `M` must be a string
+literal.
+
+Example: `BOOST_PRAGMA_MESSAGE("This header is deprecated.")`
+
+The messages issued by `BOOST_PRAGMA_MESSAGE` can be suppressed by defining the macro
+`BOOST_DISABLE_PRAGMA_MESSAGE`.]]
+
+[[`BOOST_HEADER_DEPRECATED(A)`][Defined in header `<boost/config/header_deprecated.hpp>`,
+this macro issues the message "This header is deprecated. Use `A` instead." via
+`BOOST_PRAGMA_MESSAGE`. `A` must be a string literal.
+
+Example: `BOOST_HEADER_DEPRECATED("<boost/config/workaround.hpp>")`
+
+The messages issued by `BOOST_HEADER_DEPRECATED` can be suppressed by defining the macro
+`BOOST_ALLOW_DEPRECATED_HEADERS`.]]
+]
+
+[endsect]
+
+[#config_info_macros]
+
+[section Boost Informational Macros]
+
+The following macros describe boost features; these are, generally speaking
+the only boost macros that should be tested in user code.
+
+[table
+
+[[Macro ][Header ][Description ]]
+
+[[`BOOST_VERSION`][`<boost/version.hpp>`][
+Describes the boost version number in XYYYZZ format such that:
+`(BOOST_VERSION % 100)` is the sub-minor version, `((BOOST_VERSION / 100) % 1000)`
+is the minor version, and `(BOOST_VERSION / 100000)` is the major version.
+]]
+[[`BOOST_NO_INT64_T`][`<boost/cstdint.hpp>` `<boost/stdint.h>`][
+Defined if there are no 64-bit integral types: `int64_t`, `uint64_t` etc.
+]]
+[[`BOOST_NO_INTEGRAL_INT64_T`][`<boost/cstdint.hpp>` `<boost/stdint.h>`][
+Defined if `int64_t` as defined by `<boost/cstdint.hpp>` is not usable in
+integral constant expressions.
+]]
+[[`BOOST_MSVC`][`<boost/config.hpp>`][
+Defined if the compiler is really Microsoft Visual C++, as opposed to one
+of the many other compilers that also define `_MSC_VER`. Has the same value as
+_MSC_VER.
+]]
+[[`BOOST_MSVC_FULL_VER`][`<boost/config.hpp>`][
+Defined to a normalised 9 digit version of _MSC_FULL_VER (which sometimes only has 8 digits),
+the macro has the form VVMMPPPPP where VV is the major version number, MM is the minor version number, and
+PPPPP is the compiler build number.
+]]
+[[`BOOST_GCC`][`<boost/config.hpp>`][
+Defined if the compiler is really GCC, as opposed to one
+of the many other compilers that also define `__GNUC__`. Has the value:
+`__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__`.
+]]
+[[`BOOST_INTEL`][`<boost/config.hpp>`][
+Defined if the compiler is an Intel compiler, takes the same value as the
+compiler version macro.
+]]
+[[`BOOST_CLANG`][`<boost/config.hpp>`][
+Defined to 1 if the compiler is the Clang compiler.
+]]
+[[`BOOST_WINDOWS`][`<boost/config.hpp>`][
+Defined if the Windows platform API is available.
+]]
+[[`BOOST_DINKUMWARE_STDLIB`][`<boost/config.hpp>`][
+Defined if the dinkumware standard library is in use, takes the same value
+as the Dinkumware library version macro `_CPPLIB_VER` if defined, otherwise 1.
+]]
+[[`BOOST_NO_WREGEX`][`<boost/regex.hpp>`][
+Defined if the regex library does not support wide character regular
+expressions.
+]]
+[[`BOOST_COMPILER`][`<boost/config.hpp>`][
+Defined as a string describing the name and version number of the compiler
+in use. Mainly for debugging the configuration.
+]]
+[[`BOOST_STDLIB`][`<boost/config.hpp>`][
+Defined as a string describing the name and version number of the standard
+library in use. Mainly for debugging the configuration.
+]]
+[[`BOOST_PLATFORM`][`<boost/config.hpp>`][
+Defined as a string describing the name of the platform. Mainly for debugging
+the configuration.
+]]
+]
+
+[endsect]
+
+[#deprecated_macros]
+
+[section Boost Deprecated Macros]
+
+The following have been deprecated; please use the replacements instead.
+They will be removed in a future version of boost.
+
+[table
+
+[[Deprecated Macro][Replacement][When deprecated][When removed]]
+
+[[`BOOST_NO_0X_HDR_ARRAY`][`BOOST_NO_CXX11_HDR_ARRAY`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_CHRONO`][`BOOST_NO_CXX11_HDR_CHRONO`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_CODECVT`][`BOOST_NO_CXX11_HDR_CODECVT`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_CONDITION_VARIABLE`][`BOOST_NO_CXX11_HDR_CONDITION_VARIABLE`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_FORWARD_LIST`][`BOOST_NO_CXX11_HDR_FORWARD_LIST`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_FUTURE`][`BOOST_NO_CXX11_HDR_FUTURE`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_INITIALIZER_LIST`][`BOOST_NO_CXX11_HDR_INITIALIZER_LIST`][Boost 1.50][]]
+[[`BOOST_NO_INITIALIZER_LISTS`][`BOOST_NO_CXX11_HDR_INITIALIZER_LIST`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_MUTEX`][`BOOST_NO_CXX11_HDR_MUTEX`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_RANDOM`][`BOOST_NO_CXX11_HDR_RANDOM`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_RATIO`][`BOOST_NO_CXX11_HDR_RATIO`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_REGEX`][`BOOST_NO_CXX11_HDR_REGEX`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_SYSTEM_ERROR`][`BOOST_NO_CXX11_HDR_SYSTEM_ERROR`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_THREAD`][`BOOST_NO_CXX11_HDR_THREAD`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_TUPLE`][`BOOST_NO_CXX11_HDR_TUPLE`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_TYPE_TRAITS`][`BOOST_NO_CXX11_HDR_TYPE_TRAITS`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_TYPEINDEX`][`BOOST_NO_CXX11_HDR_TYPEINDEX`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_UNORDERED_SET`][`BOOST_NO_CXX11_HDR_UNORDERED_SET`][Boost 1.50][]]
+[[`BOOST_NO_0X_HDR_UNORDERED_MAP`][`BOOST_NO_CXX11_HDR_UNORDERED_MAP`][Boost 1.50][]]
+[[`BOOST_NO_STD_UNORDERED`][`BOOST_NO_CXX11_HDR_UNORDERED_SET`][Boost 1.50][]]
+[[][][][]]
+[[`BOOST_NO_AUTO_DECLARATIONS`][`BOOST_NO_CXX11_AUTO_DECLARATIONS`][Boost 1.51][]]
+[[`BOOST_NO_AUTO_MULTIDECLARATIONS`][`BOOST_NO_CXX11_AUTO_MULTIDECLARATIONS`][Boost 1.51][]]
+[[`BOOST_NO_CHAR16_T`][`BOOST_NO_CXX11_CHAR16_T`][Boost 1.51][]]
+[[`BOOST_NO_CHAR32_T`][`BOOST_NO_CXX11_CHAR32_T`][Boost 1.51][]]
+[[`BOOST_NO_TEMPLATE_ALIASES`][`BOOST_NO_CXX11_TEMPLATE_ALIASES`][Boost 1.51][]]
+[[`BOOST_NO_CONSTEXPR`][`BOOST_NO_CXX11_CONSTEXPR`][Boost 1.51][]]
+[[`BOOST_NO_DECLTYPE`][`BOOST_NO_CXX11_DECLTYPE`][Boost 1.51][]]
+[[`BOOST_NO_DECLTYPE_N3276`][`BOOST_NO_CXX11_DECLTYPE_N3276`][Boost 1.51][]]
+[[`BOOST_NO_DEFAULTED_FUNCTIONS`][`BOOST_NO_CXX11_DEFAULTED_FUNCTIONS`][Boost 1.51][]]
+[[`BOOST_NO_DELETED_FUNCTIONS`][`BOOST_NO_CXX11_DELETED_FUNCTIONS`][Boost 1.51][]]
+[[`BOOST_NO_EXPLICIT_CONVERSION_OPERATORS`][`BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS`][Boost 1.51][]]
+[[`BOOST_NO_EXTERN_TEMPLATE`][`BOOST_NO_CXX11_EXTERN_TEMPLATE`][Boost 1.51][]]
+[[`BOOST_NO_FUNCTION_TEMPLATE_DEFAULT_ARGS`][`BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS`][Boost 1.51][]]
+[[`BOOST_NO_LAMBDAS`][`BOOST_NO_CXX11_LAMBDAS`][Boost 1.51][]]
+[[`BOOST_NO_LOCAL_CLASS_TEMPLATE_PARAMETERS`][`BOOST_NO_CXX11_LOCAL_CLASS_TEMPLATE_PARAMETERS`][Boost 1.51][]]
+[[`BOOST_NO_NOEXCEPT`][`BOOST_NO_CXX11_NOEXCEPT`][Boost 1.51][]]
+[[`BOOST_NO_NULLPTR`][`BOOST_NO_CXX11_NULLPTR`][Boost 1.51][]]
+[[`BOOST_NO_RAW_LITERALS`][`BOOST_NO_CXX11_RAW_LITERALS`][Boost 1.51][]]
+[[`BOOST_NO_RVALUE_REFERENCES`][`BOOST_NO_CXX11_RVALUE_REFERENCES`][Boost 1.51][]]
+[[`BOOST_NO_SCOPED_ENUMS`][`BOOST_NO_CXX11_SCOPED_ENUMS`][Boost 1.51][]]
+[[`BOOST_NO_STATIC_ASSERT`][`BOOST_NO_CXX11_STATIC_ASSERT`][Boost 1.51][]]
+[[`BOOST_NO_STD_UNORDERED`][`BOOST_NO_CXX11_STD_UNORDERED`][Boost 1.51][]]
+[[`BOOST_NO_UNICODE_LITERALS`][`BOOST_NO_CXX11_UNICODE_LITERALS`][Boost 1.51][]]
+[[`BOOST_NO_UNIFIED_INITIALIZATION_SYNTAX`][`BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX`][Boost 1.51][]]
+[[`BOOST_NO_VARIADIC_TEMPLATES`][`BOOST_NO_CXX11_VARIADIC_TEMPLATES`][Boost 1.51][]]
+[[`BOOST_NO_VARIADIC_MACROS`][`BOOST_NO_CXX11_VARIADIC_MACROS`][Boost 1.51][]]
+[[`BOOST_NO_NUMERIC_LIMITS_LOWEST`][`BOOST_NO_CXX11_NUMERIC_LIMITS`][Boost 1.51][]]
+[[][][][]]
+[[`BOOST_HAS_STATIC_ASSERT`][`BOOST_NO_CXX11_STATIC_ASSERT` (negated)][Boost 1.53][]]
+[[`BOOST_HAS_VARIADIC_TMPL`][`BOOST_NO_CXX11_VARIADIC_TEMPLATES` (negated)][Boost 1.53][]]
+[[`BOOST_HAS_RVALUE_REFS`][`BOOST_NO_CXX11_RVALUE_REFERENCES` (negated)][Boost 1.53][]]
+[[`BOOST_HAS_CHAR16_T`][`BOOST_NO_CXX11_CHAR16_T` (negated)][Boost 1.53][]]
+[[`BOOST_HAS_CHAR32_T`][`BOOST_NO_CXX11_CHAR32_T` (negated)][Boost 1.53][]]
+]
+
+[endsect]
+
+[section Macros for libraries with separate source code]
+
+The following macros and helper headers are of use to authors whose libraries
+include separate source code, and are intended to address several issues:
+
+* Controlling shared library symbol visibility
+* Fixing the ABI of the compiled library
+* Selecting which compiled library to link against based upon the compilers settings
+
+See [@http://www.boost.org/development/separate_compilation.html Guidelines for Authors of Boost Libraries Containing Separate Source]
+
+[section Macros controlling shared library symbol visibility]
+
+Some compilers support C++ extensions that control which symbols
+will be exported from shared libraries such as dynamic shared objects (DSO's) on Unix-like
+systems or dynamic-link libraries (DLL's) on Windows.
+
+The Microsoft VC++ compiler has long supplied
+`__declspec(dllexport)` and `__declspec(dllimport)` extensions for this purpose,
+as do virtually all other compilers targeting the Windows platform.
+
+Modern versions of the GNU GCC compiler provide the `__attribute__((visibility("default")))`
+extension to indicate that a symbol should be exported. All other symbols may be hidden by using the
+`-fvisibility-hidden` or `-fvisibility-ms-compat` compiler switches.
+
+Boost supplies several macros to make it easier to manage symbol visibility in a way that
+is portable between compilers and operating systems.
+
+[table
+[[Macro ][Description ]]
+[[`BOOST_SYMBOL_EXPORT`][
+Defines the syntax of a C++ language extension that indicates a symbol is to be exported from a shared library.
+If the compiler has no such extension, the macro is defined with no replacement text.
+]]
+[[`BOOST_SYMBOL_IMPORT`][
+Defines the syntax of a C++ language extension that indicates a symbol is to be imported from a shared library.
+If the compiler has no such extension, the macro is defined with no replacement text.
+]]
+[[`BOOST_SYMBOL_VISIBLE`][
+Defines the syntax of a C++ language extension that indicates a symbol is to be globally visible.
+If the compiler has no such extension, the macro is defined with no replacement text.
+Needed for classes that are not otherwise exported, but are used by RTTI. Examples include
+class for objects that will be thrown as exceptions or used in dynamic_casts,
+across shared library boundaries. For example, a header-only exception class might look like this:
+``
+ class BOOST_SYMBOL_VISIBLE my_exception : public std::runtime_error { ... };
+``
+Without BOOST_SYMBOL_VISIBLE, it would be impossible to catch my_exception thrown from a shared library
+compiled by GCC with the -fvisibility=hidden option.
+]]
+[[`BOOST_HAS_DECLSPEC`][
+The compiler has C++ extensions `__declspec(dllexport)` and `__declspec(dllimport)` to control
+export/import of symbols from shared libraries.
+['Deprecated. This macro is no longer necessary since BOOST_SYMBOL_EXPORT and BOOST_SYMBOL_IMPORT
+are now supplied. It is provided to support legacy code.]
+]]
+]
+
+Typical usage:
+
+[*boost/foo/config.hpp]
+
+ ...
+ #if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_FOO_DYN_LINK)
+ # if defined(BOOST_FOO_SOURCE)
+ # define BOOST_FOO_DECL BOOST_SYMBOL_EXPORT
+ # else
+ # define BOOST_FOO_DECL BOOST_SYMBOL_IMPORT
+ # endif
+ #else
+ # define BOOST_FOO_DECL
+ #endif
+ ...
+
+[*boost/foo/foo.hpp]
+
+ #include <boost/foo/config.hpp>
+ ...
+ class BOOST_FOO_DECL bar { ... };
+ ...
+ void BOOST_FOO_DECL f();
+ ...
+
+[*boost/libs/foo/src/foo.cpp]
+
+ #define BOOST_FOO_SOURCE
+ #include <boost/foo/foo.hpp>
+ ...
+ void BOOST_FOO_DECL f()
+ {
+ ...
+ }
+ ...
+
+[endsect]
+
+[section ABI Fixing]
+
+When linking against a pre-compiled library it vital that the ABI used by the
+compiler when building the library ['matches exactly] the ABI used by the code
+using the library. In this case ABI means things like the struct packing
+arrangement used, the name mangling scheme used, or the size of some types
+(enum types for example). This is separate from things like threading support,
+or runtime library variations, which have to be dealt with by build variants.
+To put this in perspective there is one compiler (Borland's) that has so many
+compiler options that make subtle changes to the ABI, that at least in theory
+there 3200 combinations, and that's without considering runtime library
+variations. Fortunately these variations can be managed by `#pragma`'s that
+tell the compiler what ABI to use for the types declared in your library.
+In order to avoid sprinkling `#pragma`'s all over the boost headers, there are
+some prefix and suffix headers that do the job. Typical usage is:
+
+[*my_library.hpp]
+
+ #ifndef MY_INCLUDE_GUARD
+ #define MY_INCLUDE_GUARD
+
+ // all includes go here:
+ ``[^[*#include <boost/config.hpp>]]``
+ #include <whatever>
+
+ ``[^[*#include <boost/config/abi_prefix.hpp>]]`` // must be the last #include
+
+ namespace boost {
+
+ // your code goes here
+
+ }
+
+ ``[^[*#include <boost/config/abi_suffix.hpp>]]`` // pops abi_prefix.hpp pragmas
+
+ #endif // include guard
+
+[*my_library.cpp]
+
+ ...
+ // nothing special need be done in the implementation file
+ ...
+
+The user can disable this mechanism by defining `BOOST_DISABLE_ABI_HEADERS`, or
+they can define `BOOST_ABI_PREFIX` and/or `BOOST_ABI_SUFFIX` to point to their
+own prefix/suffix headers if they so wish.
+
+[endsect]
+
+[section Automatic library selection]
+
+It is essential that users link to a build of a library which was built against
+the same runtime library that their application will be built against -if this
+does not happen then the library will not be binary compatible with their own
+code- and there is a high likelihood that their application will experience
+runtime crashes. These kinds of problems can be extremely time consuming and
+difficult to debug, and often lead to frustrated users and authors alike (simply
+selecting the right library to link against is not as easy as it seems when
+their are 6-8 of them to chose from, and some users seem to be blissfully
+unaware that there even are different runtimes available to them).
+
+To solve this issue, some compilers allow source code to contain `#pragma`'s that
+instruct the linker which library to link against, all the user need do is
+include the headers they need, place the compiled libraries in their library
+search path, and the compiler and linker do the rest. Boost.config supports
+this via the header `<boost/config/auto_link.hpp>`, before including this header
+one or more of the following macros need to be defined:
+
+[variablelist
+[[`BOOST_LIB_NAME`][
+Required: An identifier containing the basename of the library, for
+example 'boost_regex'.
+]]
+[[`BOOST_DYN_LINK`][
+Optional: when set link to dll rather than static library.
+]]
+[[`BOOST_LIB_DIAGNOSTIC`][
+Optional: when set the header will print out the name of the library selected
+(useful for debugging).
+]]
+]
+
+If the compiler supports this mechanism, then it will be told to link against
+the appropriately named library, the actual algorithm used to mangle the name
+of the library is documented inside `<boost/config/auto_link.hpp>` and has to
+match that used to create the libraries via bjam 's install rules.
+
+
+[*my_library.hpp]
+
+ ...
+ //
+ // Don't include auto-linking code if the user has disabled it by
+ // defining BOOST_ALL_NO_LIB, or BOOST_MY_LIBRARY_NO_LIB, or if this
+ // is one of our own source files (signified by BOOST_MY_LIBRARY_SOURCE):
+ //
+ #if !defined(BOOST_ALL_NO_LIB) && !defined(BOOST_MY_LIBRARY_NO_LIB) && !defined(BOOST_MY_LIBRARY_SOURCE)
+ # define BOOST_LIB_NAME boost_my_library
+ # ifdef BOOST_MY_LIBRARY_DYN_LINK
+ # define BOOST_DYN_LINK
+ # endif
+ # include <boost/config/auto_link.hpp>
+ #endif
+ ...
+
+[*my_library.cpp]
+
+ // define BOOST_MY_LIBRARY_SOURCE so that the header knows that the
+ // library is being built (possibly exporting rather than importing code)
+ //
+ #define BOOST_MY_LIBRARY_SOURCE
+
+ #include <boost/my_library/my_library.hpp>
+ ...
+
+[endsect]
+
+[endsect]
+
+[endsect]
+
+
+