wxwidgets/include/wx/meta/convertible.h
Vadim Zeitlin 6bbfdb157e Check that C++11 is available and remove tests for it
Don't bother checking for various C++11 features that are available in
all C++11 compilers.

Also assume that std::exception_ptr is available in all still supported
MinGW versions and remove checks for it too (see #16634).

Further simplifications remain possible, this is just the first step.
2022-10-11 00:02:29 +02:00

52 lines
1.5 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: wx/meta/convertible.h
// Purpose: Test if types are convertible
// Author: Arne Steinarson
// Created: 2008-01-10
// Copyright: (c) 2008 Arne Steinarson
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_META_CONVERTIBLE_H_
#define _WX_META_CONVERTIBLE_H_
//
// Introduce an extra class to make this header compilable with g++3.2
//
template <class D, class B>
struct wxConvertibleTo_SizeHelper
{
static char Match(B* pb);
static int Match(...);
};
// Helper to decide if an object of type D is convertible to type B (the test
// succeeds in particular when D derives from B)
template <class D, class B>
struct wxConvertibleTo
{
enum
{
value =
sizeof(wxConvertibleTo_SizeHelper<D,B>::Match(static_cast<D*>(NULL)))
==
sizeof(char)
};
};
// This is similar to wxConvertibleTo, except that when using a C++11 compiler,
// the case of D deriving from B non-publicly will be detected and the correct
// value (false) will be deduced instead of getting a compile-time error as
// with wxConvertibleTo. For pre-C++11 compilers there is no difference between
// this helper and wxConvertibleTo.
template <class D, class B>
struct wxIsPubliclyDerived
{
enum
{
value = std::is_base_of<B, D>::value && std::is_convertible<D*, B*>::value
};
};
#endif // _WX_META_CONVERTIBLE_H_