1 //===---------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===---------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___FWD_SUBRANGE_H
10 #define _LIBCPP___FWD_SUBRANGE_H
11 
12 #include <__config>
13 
14 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
15 #  pragma GCC system_header
16 #endif
17 
18 #if _LIBCPP_STD_VER >= 20
19 
20 #include <__iterator/concepts.h>
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 namespace ranges {
25 
26 enum class _LIBCPP_ENUM_VIS subrange_kind : bool { unsized, sized };
27 
28 template <input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent, subrange_kind _Kind>
29   requires(_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>)
30 class _LIBCPP_TEMPLATE_VIS subrange;
31 
32 } // namespace ranges
33 
34 _LIBCPP_END_NAMESPACE_STD
35 
36 #endif // _LIBCPP_STD_VER >= 20
37 
38 #endif // _LIBCPP___FWD_SUBRANGE_H
39