gcc/libstdc++-v3/include/std/source_location

// <source_location> -*- C++ -*-

// Copyright (C) 2020-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file include/source_location
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_SRCLOC
#define _GLIBCXX_SRCLOC 1

#if __cplusplus > 201703L && __has_builtin(__builtin_source_location)
#include <bits/c++config.h>

namespace std
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#define __cpp_lib_source_location 201907L

  /// A class that describes a location in source code.
  struct source_location
  {
  private:
    using uint_least32_t = __UINT_LEAST32_TYPE__;

  public:

    // [support.srcloc.cons], creation
    static consteval source_location
    current(const void* __p = __builtin_source_location()) noexcept
    {
      source_location __ret;
      __ret._M_impl = static_cast <const __impl*>(__p);
      return __ret;
    }

    constexpr source_location() noexcept { }

    // [support.srcloc.obs], observers
    constexpr uint_least32_t
    line() const noexcept
    { return _M_impl ? _M_impl->_M_line : 0u; }

    constexpr uint_least32_t
    column() const noexcept
    { return _M_impl ? _M_impl->_M_column : 0u; }

    constexpr const char*
    file_name() const noexcept
    { return _M_impl ? _M_impl->_M_file_name : ""; }

    constexpr const char*
    function_name() const noexcept
    { return _M_impl ? _M_impl->_M_function_name : ""; }

  private:
    struct __impl
    {
      const char* _M_file_name;
      const char* _M_function_name;
      unsigned _M_line;
      unsigned _M_column;
    };

    const __impl* _M_impl = nullptr;
  };

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++20 && __builtin_source_location
#endif // _GLIBCXX_SRCLOC