warning: use of the 'deprecated' attribute is a C++14 extension

[ashtum]

When compiling with Clang in C++11 mode using -Wpedantic, the following warning appears:

In file included from /workspace/boost/libs/asio/include/boost/asio.hpp:21:
In file included from /workspace/boost/libs/asio/include/boost/asio/any_completion_handler.hpp:20:
In file included from /workspace/boost/libs/asio/include/boost/asio/any_io_executor.hpp:23:
In file included from /workspace/boost/libs/asio/include/boost/asio/execution_context.hpp:584:
/workspace/boost/libs/asio/include/boost/asio/impl/execution_context.hpp:118:1: warning: use of the 'deprecated' attribute is a C++14 extension [-Wc++14-attribute-extensions]
  118 | BOOST_ASIO_DEPRECATED_MSG("Use make_service()")
      | ^
/workspace/boost/libs/asio/include/boost/asio/detail/config.hpp:1373:46: note: expanded from macro 'BOOST_ASIO_DEPRECATED_MSG'
 1373 | #    define BOOST_ASIO_DEPRECATED_MSG(msg) [[deprecated(msg)]]

[ashtum]

In Clang 3.7 and 3.8, the warning appears even without the -Wpedantic flag:
https://godbolt.org/z/sf8GP4s6q
https://godbolt.org/z/P9YWddbsa

[nigels-com]

So there is a check #if __has_cpp_attribute(deprecated) but for -Wpedantic compilation mode there would also need to be a __cplusplus > 201402L (C++14 or newer) check?

[nigels-com]

Pytorch has some interesting logic for (either) C++14, gcc or MSVC:

#if (defined(__cplusplus) && __cplusplus >= 201402L)
#define C10_DEPRECATED [[deprecated]]
#define C10_DEPRECATED_MESSAGE(message) [[deprecated(message)]]
#elif defined(__GNUC__)
#define C10_DEPRECATED __attribute__((deprecated))
// TODO Is there some way to implement this?
#define C10_DEPRECATED_MESSAGE(message) __attribute__((deprecated))

#elif defined(_MSC_VER)
#define C10_DEPRECATED __declspec(deprecated)
#define C10_DEPRECATED_MESSAGE(message) __declspec(deprecated(message))
#else
#warning "You need to implement C10_DEPRECATED for this compiler"
#define C10_DEPRECATED
#endif

Which does seem more -Wpedantic friendly.

[nigels-com]

clang-3.7 also seems happy with __attribute__((deprecated)) in C++11 with -Wpedantic.