The BOOST_PP_LIMIT_VARIADIC
macro
defines the maximum variadic data size supported by
the library.
Usage
BOOST_PP_LIMIT_VARIADIC
Remarks
This macro expands by default to 64. The end-user can
change this to 128 or 256 by defining this macro to either value
before including any library headers. This value can never be less
than the value of BOOST_PP_LIMIT_TUPLE.