Update test and documentation

doc/alloc_construct.qbk

@@ -116,7 +116,9 @@ reverse order by calling `std::allocator_traits<A>::destroy(a, &p[j])`.]]]]]
 [[`template<class A, class T, class I> void alloc_construct_n(A& a, T* p,
 std::size_t n, I begin);`]
 [[variablelist
-[[Requires][`A` is an /Allocator/; `I` is an /InputIterator/]]
+[[Requires]
+[[itemized_list
+[`A` is an /Allocator/][`I` is an /InputIterator/]]]]
 [[Effects]
 [Constructs each `i`-th element in order by calling
 `std::allocator_traits<A>::construct(a, &p[i], *begin++])`.]]
@@ -140,7 +142,7 @@ without going through the supplied allocator.
 
 Glen Fernandes originally implemented this functionality in Boost.Smart_Ptr and
 later moved these functions to Boost.Core for use in other Boost libraries,
-such as Boost.Multi_Array.
+such as Boost.Multi_Array and Boost.Histogram.
 
 [endsect]
 

doc/exchange.qbk

@@ -18,7 +18,8 @@ Distributed under the Boost Software License, Version 1.0.
 
 The header <boost/core/exchange.hpp> provides the function template
 `boost::exchange` which is an implementation of the `std::exchange`
-function introduced in C++14.
+function introduced in C++14. `boost::exchange(o, v)` replaces the
+value of `o` with `v` and returns the old value of `o`.
 
 [endsect]
 

doc/first_scalar.qbk

@@ -16,10 +16,11 @@ Distributed under the Boost Software License, Version 1.0.
 
 [section Overview]
 
-The header <boost/core/first_scalar.hpp> provides the function template
+The header <boost/core/first_scalar.hpp> provides the function templates
 `boost::first_scalar` that can be used to obtain a pointer to the first scalar
-element of an array. Given a pointer of type `T*` it returns a pointer of type
-`remove_all_extents_t<T>*`.
+element of an array. Given a pointer of type `T*` they return a pointer of
+type `remove_all_extents_t<T>*`. The functions are `constexpr` and can be used
+in constant expressions.
 
 [endsect]
 
@@ -80,4 +81,11 @@ noexcept;`]
 
 [endsect]
 
+[section History]
+
+Glen Fernandes implemented `first_scalar`. Peter Dimov suggested a change for
+GCC to support an additional `constexpr` use.
+
+[endsect]
+
 [endsect]

test/alloc_construct_cxx11_test.cpp

@@ -47,15 +47,14 @@ struct creator {
         ::operator delete(ptr);
     }
 
-    template<class U, class V>
-    void construct(U* ptr, const V& value) {
-        ::new(static_cast<void*>(ptr)) U(value + 1);
+    template<class V>
+    void construct(type* ptr, const V& value) {
+        ::new(static_cast<void*>(ptr)) type(value + 1);
         ++type::count;
     }
 
-    template<class U>
-    void destroy(U* ptr) {
-        ptr->~U();
+    void destroy(type* ptr) {
+        ptr->~type();
         --type::count;
     }
 };