#if !defined(TORCH_STABLE_ONLY) && !defined(TORCH_TARGET_VERSION)
// Copyright (c) Facebook, Inc. and its affiliates.
// All rights reserved.
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree.

#pragma once

#include <cstring>
#include <system_error>

#include <fmt/format.h>

namespace fmt {

template <>
struct formatter<std::error_category> {
  constexpr auto parse(format_parse_context& ctx) const {
    return ctx.begin();
  }

  template <typename FormatContext>
  auto format(const std::error_category& cat, FormatContext& ctx) const {
    if (std::strcmp(cat.name(), "generic") == 0) {
      return fmt::format_to(ctx.out(), "errno");
    } else {
      return fmt::format_to(ctx.out(), "{} error", cat.name());
    }
  }
};

template <>
struct formatter<std::error_code> {
  constexpr auto parse(format_parse_context& ctx) const {
    return ctx.begin();
  }

  template <typename FormatContext>
  auto format(const std::error_code& err, FormatContext& ctx) const {
    return fmt::format_to(
        ctx.out(), "({}: {} - {})", err.category(), err.value(), err.message());
  }
};

} // namespace fmt

namespace c10d::detail {

inline std::error_code lastError() noexcept {
  return std::error_code{errno, std::generic_category()};
}

} // namespace c10d::detail

#else
#error "This file should not be included when either TORCH_STABLE_ONLY or TORCH_TARGET_VERSION is defined."
#endif  // !defined(TORCH_STABLE_ONLY) && !defined(TORCH_TARGET_VERSION)
