[boost] Deprecation indication

Hi, Is there anything in eg. boost.config or other that expands to a compiler indication that something is "deprecated", possibly with a message that appears only once? It may expand to `[[deprecated]]` or `[[deprecated("reason")]]` if available and supported, or `__declspec(deprecated)` / `__declspec(deprecated("reason"))`, `__attribute__ ((deprecated))` ... I could not find anything in boost.config. Has anyone an example of this in boost? Is there any indication/policy in boost about deprecation? Thanks in advance, Raffi