| .. Data Types/Miscellaneous//void_ |100 |
| |
| void\_ |
| ====== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| struct void\_ |
| { |
| typedef void\_ type; |
| }; |
| |
| template< typename T > struct is_void; |
| |
| |
| Description |
| ----------- |
| |
| ``void_`` is a generic type placeholder representing "nothing". |
| |
| .. In many cases, returning ``void_`` from a metafunction to signal |
| an absence of the requested data leads to a simpler user code than |
| having a separate metafunction specifically for the purpose of |
| performing the corresponding check. |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/void.hpp> |
| |
| |
| See also |
| -------- |
| |
| |Data Types|, |pair|, |empty_base|, |bool_|, |int_|, |integral_c| |
| |
| |
| .. copyright:: Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams |
| 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) |
