bslmf_addcv.h

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/// @file bslmf_addcv.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bslmf_addcv.h                                                      -*-C++-*-
#ifndef INCLUDED_BSLMF_ADDCV
#define INCLUDED_BSLMF_ADDCV
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bslmf_addcv bslmf_addcv
/// @brief  Provide a meta-function for adding top-level cv-qualifiers.
/// @addtogroup bsl
/// @{
/// @addtogroup bslmf
/// @{
/// @addtogroup bslmf_addcv
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bslmf_addcv-purpose"> Purpose</a>
/// * <a href="#bslmf_addcv-classes"> Classes </a>
/// * <a href="#bslmf_addcv-description"> Description </a>
///   * <a href="#bslmf_addcv-usage"> Usage </a>
///     * <a href="#bslmf_addcv-example-1-adding-a-const-qualifier-and-a-volatile-qualifier-to-a-type"> Example 1: Adding a const-Qualifier and a volatile-Qualifier to a Type </a>
///
/// # Purpose {#bslmf_addcv-purpose}
/// Provide a meta-function for adding top-level cv-qualifiers.
///
/// # Classes {#bslmf_addcv-classes}
///
/// -  bsl::add_cv: meta-function for adding top-level cv-qualifiers
/// -  bsl::add_cv_t: alias to the return type of the `bsl::add_cv` meta-function
///
/// @see  bslmf_removecv
///
/// # Description {#bslmf_addcv-description}
/// This component defines a meta-function, `bsl::add_cv` and
/// declares an `bsl::add_cv_t` alias to the return type of the `bsl::add_cv`,
/// that may be used to add a top-level `const`-qualifier and a top-level
/// `volatile`-qualifier to a type if it is not a reference type, nor a function
/// type, nor already `const`-qualified and `volatile`-qualified at the
/// top-level.
///
/// `bsl::add_cv` and `bsl::add_cv_t` meet the requirements of the `add_cv`
/// template defined in the C++11 standard [meta.trans.cv].
///
/// ## Usage {#bslmf_addcv-usage}
///
///
/// In this section we show intended use of this component.
///
/// ### Example 1: Adding a const-Qualifier and a volatile-Qualifier to a Type {#bslmf_addcv-example-1-adding-a-const-qualifier-and-a-volatile-qualifier-to-a-type}
///
///
/// Suppose that we want to add a `const`-qualifier and a `volatile`-qualifier
/// to a particular type.
///
/// First, we create two `typedef`s -- a `const`-qualified and
/// `volatile`-qualified type (`MyCvType`) and the same type without the
/// cv-qualifiers (`MyType`):
/// @code
/// typedef int                MyType;
/// typedef const volatile int MyCvType;
/// @endcode
/// Now, we add a `const`-qualifier and a `volatile`-qualifier to `MyType` using
/// `bsl::add_cv` and verify that the resulting type is the same as `MyCvType`:
/// @code
/// assert(true == (bsl::is_same<bsl::add_cv<MyType>::type, MyCvType>::value));
/// @endcode
/// Finally, if the current compiler supports alias templates C++11 feature, we
/// add a `const`-qualifier and a `volatile`-qualifier to `MyType` using
/// `bsl::add_cv_t` and verify that the resulting type is the same as
/// `MyCvType`:
/// @code
/// #ifdef BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES
///   assert(true == (bsl::is_same<bsl::add_cv_t<MyType>, MyCvType>::value));
/// #endif
/// @endcode
/// Note, that the `bsl::add_cv_t` avoids the `::type` suffix and `typename`
/// prefix when we want to use the result of the `bsl::add_cv` meta-function in
/// templates.
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bslmf
 * @{
 */
/** @addtogroup bslmf_addcv
 * @{
 */
 
#include <bslscm_version.h>
 
#include <bslmf_addconst.h>
#include <bslmf_addvolatile.h>
 
#include <bsls_compilerfeatures.h>
 
namespace bsl {
 
                         // =============
                         // struct add_cv
                         // =============
 
/// This `struct` template implements the `add_cv` meta-function defined in
/// the C++11 standard [meta.trans.cv], providing an alias, `type`, that
/// returns the result.  If the (template parameter) `t_TYPE` is not a
/// reference type, nor a function type, nor already `const`-qualified and
/// `volatile`-qualified at the top-level, then `type` is an alias to
/// `t_TYPE` with a top-level `const`-qualifier and a `volatile`-qualifier
/// added; otherwise, `type` is an alias to `t_TYPE`.
template <class t_TYPE>
struct add_cv {
 
    // PUBLIC TYPES
 
    /// This `typedef` is an alias to the (template parameter) `t_TYPE` with
    /// a top-level `const`-qualifier and `volatile`-qualifier added if
    /// `t_TYPE` is not a reference type, nor a function type, nor already
    /// `const`-qualified and `volatile`-qualified at the top-level;
    /// otherwise, `type` is an alias to `t_TYPE`.
    typedef typename add_const<typename add_volatile<t_TYPE>::type>::type type;
};
 
#ifdef BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES
 
// ALIASES
 
/// `add_cv_t` is an alias to the return type of the `bsl::add_cv`
/// meta-function.  Note, that the `add_cv_t` avoids the `::type` suffix and
/// `typename` prefix when we want to use the result of the `bsl::add_cv` in
/// templates.
template <class t_TYPE>
using add_cv_t = typename add_cv<t_TYPE>::type;
#endif  // BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES
 
}  // close namespace bsl
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2013 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */