Since a nonzero id is only passed when BOOST_SYSTEM_AVOID_STD_GENERIC_CATEGORY or BOOST_SYSTEM_AVOID_STD_SYSTEM_CATEGORY is defined, and since id is only stored into _Addr when the MS STL is 14x, but none of these macros are defined in this case, this code should be dead and it should be possible to remove it.
... as this creates problems for the MS STL (https://github.com/microsoft/STL/pull/3176).
Since a nonzero
idis only passed whenBOOST_SYSTEM_AVOID_STD_GENERIC_CATEGORYorBOOST_SYSTEM_AVOID_STD_SYSTEM_CATEGORYis defined, and sinceidis only stored into_Addrwhen the MS STL is 14x, but none of these macros are defined in this case, this code should be dead and it should be possible to remove it.