take functor by value and return it

Author: kevinushey

examples/boost-simd-for-each.cpp

@@ -28,8 +28,7 @@ class Accumulator
 // [[Rcpp::export]]
 double vectorProd(NumericVector x) {
    auto accumulator = Accumulator();
-   boost::simd::for_each(x.begin(), x.end(), accumulator);
-   return accumulator;
+   return boost::simd::for_each(x.begin(), x.end(), accumulator);
 }
 
 /*** R

inst/include/RcppParallel/simd/for_each.h

@@ -5,7 +5,7 @@ namespace boost {
 namespace simd {
 
 template <typename T, typename F>
-void for_each(const T* it, const T* end, F& f)
+F for_each(const T* it, const T* end, F f)
 {
    typedef boost::simd::pack<T> vT;
    static const std::size_t N = vT::static_size;
@@ -20,6 +20,8 @@ void for_each(const T* it, const T* end, F& f)
 
    for (; it != end; ++it)
       f(*it);
+   
+   return f;
 }
 
 } // namespace simd