Added BOOST_INLINE_VARIABLE macro.

The BOOST_INLINE_VARIABLE macro can be used to mark C++17 inline variables in
contexts where omitting the inline keyword is still acceptable on older
compilers.

This commit also adds the missing docs for BOOST_NO_CXX17_INLINE_VARIABLES.
This commit is contained in:
Andrey Semashev
2019-10-02 17:16:55 +03:00
parent cda275e884
commit 38df8ca0d7
2 changed files with 25 additions and 1 deletions

View File

@ -936,7 +936,7 @@ 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.]]
[[`BOOST_CXX14_CONSTEXPR`][This macro works similar to `BOOST_CONSTEXPR`, but expands to `constexpr` only if the C++14 "relaxed" `constexpr` is available.]]
]
[endsect]
@ -955,6 +955,21 @@ that are not yet supported by a particular compiler or library.
[[`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`.]]
[[`BOOST_NO_CXX17_INLINE_VARIABLES`][The compiler does not support `inline` variables.]]
]
[endsect]
[#config_17_for_14]
[section Macros that allow use of C++17 features with C++14 or earlier compilers]
The following macros allow use of C++17 features even with compilers that do not yet
provide compliant C++17 support.
[table
[[Macro ][ Description ]]
[[`BOOST_INLINE_VARIABLE`][This macro expands to `inline` on compilers that support C++17 inline variables and to nothing otherwise. Users may need to check for `BOOST_NO_CXX17_INLINE_VARIABLES` for further adjustments to the code.]]
]
[endsect]

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@ -986,6 +986,15 @@ namespace std{ using ::type_info; }
#define BOOST_CXX14_CONSTEXPR constexpr
#endif
//
// C++17 inline variables
//
#if !defined(BOOST_NO_CXX17_INLINE_VARIABLES)
#define BOOST_INLINE_VARIABLE inline
#else
#define BOOST_INLINE_VARIABLE
#endif
//
// Unused variable/typedef workarounds:
//