Component bslmf_memberfunctionpointertraits [Package bslmf]

Provide meta-functions to detect member function pointer traits. More...

Namespaces
namespace	bslmf
Defines
#define	bslmf_MemberFunctionPointerTraits   bslmf::MemberFunctionPointerTraits
#define	bslmf_IsMemberFunctionPointer   bslmf::IsMemberFunctionPointer
#define	bslmf_MemberFunctionPointerTraitsImp   bslmf::MemberFunctionPointerTraits_Imp

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Detailed Description

Outline

• Purpose
• Classes
• Description
  • Usage

Purpose:

Provide meta-functions to detect member function pointer traits.

Classes:

bslmf::MemberFunctionPointerTraits

meta-function for detecting member

function pointer traits bslmf::IsMemberFunctionPointer: meta-function to determine if a type is a member function pointer

See also:

Component bslmf_functionpointertraits

Description:

This component provides meta-functions for determining the traits of a member function pointer. Two meta-functions are provided: bslmf::IsMemberFunctionPointer, and bslmf::MemberFunctionPointerTraits. bslmf::IsMemberFunctionPointer tests if a given type is a supported member function pointer. bslmf::MemberFunctionPointerTraits determines the traits of a member function type, including the type of the object that it is a member of, its result type, and the type of its list of arguments.

Note that, in order to support pre-C++11 compilers in a manageable way, only member functions with up to 14 arguments and no C-style (varargs) elipses are supported on all platforms by this component. When variadic templates are available, any number of arguments are supported. C-style elipses are not supported by this component at all. To identify all member function pointers see bslmf_ismemberfunctionpointer.

Usage:

Define the following function types:

  typedef void (*VoidFunc0)();

and the following struct with the following members:

  struct MyTestClass {
      static void voidFunc0() {}
      int func1(int) { return 0; }
      int func2(int, int) { return 1; }
  };

In order to deduce the types of voidFunc0 and func1, we will use the C++ template system to get two auxiliary functions:

  template <class t_TYPE>
  void checkNotMemberFunctionPointer(t_TYPE object)
  {
      assert(0 == bslmf::IsMemberFunctionPointer<t_TYPE>::value);
  }

  template <class t_BSLMF_RETURN, class t_ARGS, class t_TYPE>
  void checkMemberFunctionPointer(t_TYPE object)
  {
      assert(1 == bslmf::IsMemberFunctionPointer<t_TYPE>::value);
      typedef typename bslmf::MemberFunctionPointerTraits<t_TYPE>::ResultType
          ResultType;
      typedef typename
                     bslmf::MemberFunctionPointerTraits<t_TYPE>::ArgumentList
          ArgumentList;
      assert(1 == (bsl::is_same<ResultType, t_BSLMF_RETURN>::value));
      assert(1 == (bsl::is_same<ArgumentList, t_ARGS>::value));
  }

The following program should compile and run without errors:

  void usageExample()
  {
      assert(0 == bslmf::IsMemberFunctionPointer<int>::value);
      assert(0 == bslmf::IsMemberFunctionPointer<int>::value);

      checkNotMemberFunctionPointer(&MyTestClass::voidFunc0);
      checkMemberFunctionPointer<int, bslmf::TypeList1<int> >(
                                                        &MyTestClass::func1);
      checkMemberFunctionPointer<int, bslmf::TypeList2<int, int> >(
                                                        &MyTestClass::func2);
  }

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Define Documentation

#define bslmf_MemberFunctionPointerTraits   bslmf::MemberFunctionPointerTraits

#define bslmf_IsMemberFunctionPointer   bslmf::IsMemberFunctionPointer

#define bslmf_MemberFunctionPointerTraitsImp   bslmf::MemberFunctionPointerTraits_Imp