text: //---------------------------------------------------------------------------//
  // Copyright (c) 2013-2015 Kyle Lutz <kyle.r.lutz@gmail.com>
  //
  // Distributed under the Boost Software License, Version 1.0
  // See accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt
  //
  // See http://kylelutz.github.com/compute for more information.
  //---------------------------------------------------------------------------//
  
  #ifndef BOOST_COMPUTE_UTILITY_INVOKE_HPP
  #define BOOST_COMPUTE_UTILITY_INVOKE_HPP
  
  #include <boost/preprocessor/enum.hpp>
  #include <boost/preprocessor/repetition.hpp>
  
  #include <boost/compute/config.hpp>
  #include <boost/compute/command_queue.hpp>
  #include <boost/compute/detail/meta_kernel.hpp>
  #include <boost/compute/container/detail/scalar.hpp>
  #include <boost/compute/type_traits/result_of.hpp>
  
  namespace boost {
  namespace compute {
  
  #define BOOST_COMPUTE_DETAIL_INVOKE_ARG(z, n, unused) \
      BOOST_PP_COMMA_IF(n) k.var<BOOST_PP_CAT(T, n)>("arg" BOOST_PP_STRINGIZE(n))
  
  #define BOOST_COMPUTE_DETAIL_INVOKE_ADD_ARG(z, n, unused) \
      k.add_set_arg("arg" BOOST_PP_STRINGIZE(n), BOOST_PP_CAT(arg, n));
  
  #define BOOST_COMPUTE_DETAIL_DEFINE_INVOKE(z, n, unused) \
  template<class Function, BOOST_PP_ENUM_PARAMS(n, class T)> \
  inline typename result_of<Function(BOOST_PP_ENUM_PARAMS(n, T))>::type \
  invoke(const Function& function, command_queue& queue, BOOST_PP_ENUM_BINARY_PARAMS(n, const T, &arg)) \
  { \
      typedef typename result_of<Function(BOOST_PP_ENUM_PARAMS(n, T))>::type result_type; \
      detail::meta_kernel k("invoke"); \
      detail::scalar<result_type> result(queue.get_context()); \
      const size_t result_arg = k.add_arg<result_type *>(memory_object::global_memory, "result"); \
      BOOST_PP_REPEAT(n, BOOST_COMPUTE_DETAIL_INVOKE_ADD_ARG, ~) \
      k << "*result = " << function( \
          BOOST_PP_REPEAT(n, BOOST_COMPUTE_DETAIL_INVOKE_ARG, ~) \
      ) << ";"; \
      k.set_arg(result_arg, result.get_buffer()); \
      k.exec(queue); \
      return result.read(queue); \
  }
  
  BOOST_PP_REPEAT_FROM_TO(1, BOOST_COMPUTE_MAX_ARITY, BOOST_COMPUTE_DETAIL_DEFINE_INVOKE, ~)
  
  #undef BOOST_COMPUTE_DETAIL_INVOKE_ARG
  #undef BOOST_COMPUTE_DETAIL_INVOKE_ADD_ARG
  #undef BOOST_COMPUTE_DETAIL_DEFINE_INVOKE
  
  #ifdef BOOST_COMPUTE_DOXYGEN_INVOKED
  /// Invokes \p function with \p args on \p queue.
  ///
  /// For example, to invoke the builtin abs() function:
  /// \code
  /// int result = invoke(abs<int>(), queue, -10); // returns 10
  /// \endcode
  template<class Function, class... Args>
  inline typename result_of<Function(Args...)>::type
  invoke(const Function& function, command_queue& queue, const Args&... args);
  #endif // BOOST_COMPUTE_DOXYGEN_INVOKED
  
  } // end compute namespace
  } // end boost namespace
  
  #endif // BOOST_COMPUTE_UTILITY_INVOKE_HPP
  