The MPL Reference Manual: BOOST_MPL_LIMIT_SET_SIZE

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# BOOST_MPL_LIMIT_SET_SIZE

### Synopsis

    #if !defined(BOOST_MPL_LIMIT_SET_SIZE)
    #   define BOOST_MPL_LIMIT_SET_SIZE \
            implementation-defined integral constant \
    /**/
    #endif

### Description

`BOOST_MPL_LIMIT_SET_SIZE` is an overridable configuration macro regulating the maximum arity of the `set`'s and `set_c`'s variadic forms. In this implementation of the library, `BOOST_MPL_LIMIT_SET_SIZE` has a default value of 20. To override the default limit, define `BOOST_MPL_LIMIT_SET_SIZE` to the desired maximum arity rounded up to the nearest multiple of ten before including any library header. [Note: Overriding will take effect only if the library is configured not to use preprocessed headers. See BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS for more information. — end note]

### Example

    #define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS
    #define BOOST_MPL_LIMIT_SET_SIZE 10
    #include <boost/mpl/set.hpp>

    using namespace boost::mpl;

    typedef set_c<int,1> s_1;
    typedef set_c<int,1,2,3,4,5,6,7,8,9,10> s_10;
    // typedef set_c<int,1,2,3,4,5,6,7,8,9,10,11> s_11; // error!

### See also

Configuration, BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS, BOOST_MPL_LIMIT_MAP_SIZE