1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___CXX03___FUNCTIONAL_BIND_H 11 #define _LIBCPP___CXX03___FUNCTIONAL_BIND_H 12 13 #include <__cxx03/__config> 14 #include <__cxx03/__functional/weak_result_type.h> 15 #include <__cxx03/__fwd/functional.h> 16 #include <__cxx03/__type_traits/decay.h> 17 #include <__cxx03/__type_traits/invoke.h> 18 #include <__cxx03/__type_traits/is_reference_wrapper.h> 19 #include <__cxx03/__type_traits/is_void.h> 20 #include <__cxx03/__type_traits/remove_cvref.h> 21 #include <__cxx03/cstddef> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 29 template <class _Tp> 30 struct is_bind_expression 31 : _If< _IsSame<_Tp, __remove_cvref_t<_Tp> >::value, false_type, is_bind_expression<__remove_cvref_t<_Tp> > > {}; 32 33 template <class _Tp> 34 struct is_placeholder 35 : _If< _IsSame<_Tp, __remove_cvref_t<_Tp> >::value, 36 integral_constant<int, 0>, 37 is_placeholder<__remove_cvref_t<_Tp> > > {}; 38 39 namespace placeholders { 40 41 template <int _Np> 42 struct __ph {}; 43 44 // C++17 recommends that we implement placeholders as `inline constexpr`, but allows 45 // implementing them as `extern <implementation-defined>`. Libc++ implements them as 46 // `extern const` in all standard modes to avoid an ABI break in C++03: making them 47 // `inline constexpr` requires removing their definition in the shared library to 48 // avoid ODR violations, which is an ABI break. 49 // 50 // In practice, since placeholders are empty, `extern const` is almost impossible 51 // to distinguish from `inline constexpr` from a usage stand point. 52 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<1> _1; 53 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<2> _2; 54 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<3> _3; 55 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<4> _4; 56 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<5> _5; 57 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<6> _6; 58 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<7> _7; 59 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<8> _8; 60 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<9> _9; 61 _LIBCPP_EXPORTED_FROM_ABI extern const __ph<10> _10; 62 63 } // namespace placeholders 64 65 template <int _Np> 66 struct is_placeholder<placeholders::__ph<_Np> > : public integral_constant<int, _Np> {}; 67 68 _LIBCPP_END_NAMESPACE_STD 69 70 #endif // _LIBCPP___CXX03___FUNCTIONAL_BIND_H 71