bslmf_ismemberpointer.h

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/// @file bslmf_ismemberpointer.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bslmf_ismemberpointer.h                                            -*-C++-*-
#ifndef INCLUDED_BSLMF_ISMEMBERPOINTER
#define INCLUDED_BSLMF_ISMEMBERPOINTER
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bslmf_ismemberpointer bslmf_ismemberpointer
/// @brief  Provide a compile-time check for non-static member pointer types.
/// @addtogroup bsl
/// @{
/// @addtogroup bslmf
/// @{
/// @addtogroup bslmf_ismemberpointer
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bslmf_ismemberpointer-purpose"> Purpose</a>
/// * <a href="#bslmf_ismemberpointer-classes"> Classes </a>
/// * <a href="#bslmf_ismemberpointer-description"> Description </a>
///   * <a href="#bslmf_ismemberpointer-usage"> Usage </a>
///     * <a href="#bslmf_ismemberpointer-example-1-verify-member-pointer-types"> Example 1: Verify Member Pointer Types </a>
///
/// # Purpose {#bslmf_ismemberpointer-purpose}
/// Provide a compile-time check for non-static member pointer types.
///
/// # Classes {#bslmf_ismemberpointer-classes}
///
/// -  bsl::is_member_pointer: standard meta-function for member pointer types
/// -  bsl::is_member_pointer_v: the result value of the standard meta-function
///
/// @see  bslmf_ismemberfunctionpointer, bslmf_ismemberobjectpointer
///
/// # Description {#bslmf_ismemberpointer-description}
/// This component defines a meta-function,
/// `bsl::is_member_pointer` and a template variable `bsl::is_member_pointer_v`,
/// that represents the result value of the `bsl::is_member_pointer`
/// meta-function, that may be used to query whether a type is a pointer to
/// non-static member type.
///
/// `bsl::is_member_pointer` meets the requirements of the `is_member_pointer`
/// template defined in the C++11 standard [meta.unary.comp].
///
/// Note that the template variable `is_member_pointer_v` is defined in the
/// C++17 standard as an inline variable.  If the current compiler supports the
/// inline variable C++17 compiler feature, `bsl::is_member_pointer_v` is
/// defined as an `inline constexpr bool` variable.  Otherwise, if the compiler
/// supports the variable templates C++14 compiler feature,
/// `bsl::is_member_pointer_v` is defined as a non-inline `constexpr bool`
/// variable.  See `BSLS_COMPILERFEATURES_SUPPORT_INLINE_VARIABLES` and
/// `BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES` macros in
/// bsls_compilerfeatures component for details.
///
/// ## Usage {#bslmf_ismemberpointer-usage}
///
///
/// In this section we show intended use of this component.
///
/// ### Example 1: Verify Member Pointer Types {#bslmf_ismemberpointer-example-1-verify-member-pointer-types}
///
///
/// Suppose that we want to assert whether a set of types are member pointer
/// types.
///
/// First, we create a user-defined type `MyStruct`:
/// @code
/// struct MyStruct
/// {
/// };
/// @endcode
/// Now, we create three `typedef`s -- a member object pointer type, a member
/// function pointer type and a general function pointer type:
/// @code
/// typedef int MyStruct::* DataMemPtr;
/// typedef int (MyStruct::*MyStructMethodPtr) ();
/// typedef int (*MyFunctionPtr) ();
/// @endcode
/// Finally, we instantiate the `bsl::is_member_pointer` template for various
/// types and assert the `value` static data member of each instantiation:
/// @code
/// assert(false == bsl::is_member_pointer<int*>::value);
/// assert(false == bsl::is_member_pointer<MyFunctionPtr>::value);
/// assert(true  == bsl::is_member_pointer<DataMemPtr>::value);
/// assert(true  == bsl::is_member_pointer<MyStructMethodPtr>::value);
/// @endcode
/// Note that if the current compiler supports the variable templates C++14
/// feature then we can re-write the snippet of code above using the
/// `bsl::is_member_pointer_v` variable as follows:
/// @code
/// #ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
///   assert(false == bsl::is_member_pointer_v<int*>);
///   assert(false == bsl::is_member_pointer_v<MyFunctionPtr>);
///   assert(true  == bsl::is_member_pointer_v<DataMemPtr>);
///   assert(true  == bsl::is_member_pointer_v<MyStructMethodPtr>);
/// #endif
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bslmf
 * @{
 */
/** @addtogroup bslmf_ismemberpointer
 * @{
 */
 
#include <bslscm_version.h>
 
#include <bslmf_integralconstant.h>
 
#include <bsls_compilerfeatures.h>
#include <bsls_keyword.h>
#include <bsls_platform.h>
 
#ifndef BDE_DONT_ALLOW_TRANSITIVE_INCLUDES
#include <bslmf_ismemberfunctionpointer.h>
#include <bslmf_ismemberobjectpointer.h>
#endif
 
namespace bsl {
 
                         // ========================
                         // struct is_member_pointer
                         // ========================
 
/// This `struct` template implements the `is_member_pointer` meta-function
/// defined in the C++11 standard [meta.unary.comp] to determine if the
/// (template parameter) `t_TYPE` is a member pointer type.  This `struct`
/// derives from `bsl::true_type` if the `t_TYPE` is a member pointer type,
/// and from `bsl::false_type` otherwise.  Additional specializations are
/// provided below to give the correct answer in all cases.
template <class t_TYPE>
struct is_member_pointer : false_type {
};
 
/// This partial specialization provides the `true_type` result for a
/// (cv-unqualified) pointer-to-member type.  Note that additional partial
/// specializations are required to handle the cv-qualified cases.
template <class t_TARGET_TYPE, class t_HOST_TYPE>
struct is_member_pointer<t_TARGET_TYPE t_HOST_TYPE::*> : true_type {
};
 
/// This partial specialization provides the `true_type` result for a
/// `const`-qualified pointer-to-member type.
template <class t_TARGET_TYPE, class t_HOST_TYPE>
struct is_member_pointer<t_TARGET_TYPE t_HOST_TYPE::*const> : true_type {
};
 
/// This partial specialization provides the `true_type` result for a
/// `volatile`-qualified pointer-to-member type.
template <class t_TARGET_TYPE, class t_HOST_TYPE>
struct is_member_pointer<t_TARGET_TYPE t_HOST_TYPE::*volatile> : true_type {
};
 
/// This partial specialization provides the `true_type` result for a
/// `const volatile`-qualified pointer-to-member type.
template <class t_TARGET_TYPE, class t_HOST_TYPE>
struct is_member_pointer<t_TARGET_TYPE t_HOST_TYPE::*const volatile>
: true_type {
};
 
#ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
/// This template variable represents the result value of the
/// `bsl::is_member_pointer` meta-function.
template <class t_TYPE>
BSLS_KEYWORD_INLINE_VARIABLE constexpr bool is_member_pointer_v =
                                              is_member_pointer<t_TYPE>::value;
#endif
 
#if defined(BSLS_PLATFORM_CMP_MSVC)    \
 &&   BSLS_PLATFORM_CMP_VERSION < 1910 \
 &&!((BSLS_PLATFORM_CMP_VERSION == 1900) && defined(BSLS_PLATFORM_CPU_64_BIT))
// MSVC 2013 (and earlier) has two bugs that affect this component.  First,
// it does not match partial specializations for cv-qualified pointer-to-member
// types, requiring a general stripping of cv-qualifiers for all types to get
// the right result.  Secondly, pointer-to-cv-qualified-member-function fails
// to match the partial specialization at all, so fall back on trying to match
// a member function with exactly the right signature using variadic templates,
// which apparently does work.  Note that this bug also appears to affect the
// MSVC 2015 compiler, but only for 32-bit builds.
 
template <class t_TYPE>
struct is_member_pointer<const t_TYPE> : is_member_pointer<t_TYPE>::type {
    // The 'const'-qualified (template parameter) 't_TYPE' is a member pointer
    // if the corresponding unqualified 't_TYPE' is a member pointer.
};
 
template <class t_TYPE>
struct is_member_pointer<volatile t_TYPE> : is_member_pointer<t_TYPE>::type {
    // The 'volatile'-qualified (template parameter) 't_TYPE' is a member
    // pointer if the corresponding unqualified 't_TYPE' is a member pointer.
};
 
template <class t_TYPE>
struct is_member_pointer<const volatile t_TYPE>
: is_member_pointer<t_TYPE>::type {
    // The 'const volatile'-qualified (template parameter) 't_TYPE' is a member
    // pointer if the corresponding unqualified 't_TYPE' is a member pointer.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...)> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) volatile> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const volatile>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...)> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) volatile> : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const volatile>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
#if defined(BSLS_COMPILERFEATURES_SUPPORT_REF_QUALIFIERS)
// Only MSVC 2015 32-bit builds get here
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) volatile &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const volatile &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) volatile &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const volatile &>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) volatile &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...) const volatile &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) volatile &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
 
template <class RESULT, class HOST, class... ARGS>
struct is_member_pointer<RESULT (HOST::*)(ARGS...,...) const volatile &&>
    : true_type {
    // This partial specialization for non-cv-qualified pointer-to-member types
    // derives from 'true_type' if the specified (template parameter) 'type' is
    // a function type.
};
#endif  // Reference-qualifier support for MSVC 2015
 
#endif  // MSVC workarounds
 
}  // 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 ----------------------------------
 
/** @} */
/** @} */
/** @} */