microfmt_extern.hpp

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// SPDX-FileCopyrightText: 2026 Jarosław Pelczar <jarek@jpelczar.com>
//
// SPDX-License-Identifier: BSD-2-Clause
 
#pragma once
 
#include "microfmt.hpp"
 
#if defined(MICROFMT_SHARED_BUILD)
// MICROFMT_API (see detail/compat.hpp) is the export attribute here --
// MICROFMT_SHARED_BUILD is defined, so it expands to `__declspec(dllexport)`
// / default visibility, never plain `inline` -- marking these explicit
// instantiation *definitions* as publicly visible symbols so that the
// `extern template` declarations below (seen by ordinary MICROFMT_SHARED
// consumers) can actually bind to them at link time.
#define MICROFMT_FORMATTER_INSTANCE(...)                                                                               \
  template struct MICROFMT_API microfmt::formatter<__VA_ARGS__>;                                                       \
  template MICROFMT_API void microfmt::detail::format_type_thunk<__VA_ARGS__>(const void *, microfmt::string_view,     \
                                                                              const microfmt::sink &)
#elif defined(MICROFMT_SHARED)
// MICROFMT_API here expands to `__declspec(dllimport)` on MSVC (and to
// nothing elsewhere) -- MSVC requires the `extern template` declaration
// importing a dllexport-instantiated template to itself be decorated
// dllimport, or it silently re-instantiates its own local copy instead of
// binding to the shared library's definition above.
#define MICROFMT_FORMATTER_INSTANCE(...)                                                                               \
  extern template struct MICROFMT_API microfmt::formatter<__VA_ARGS__>;                                                \
  extern template MICROFMT_API void microfmt::detail::format_type_thunk<__VA_ARGS__>(                                  \
      const void *, microfmt::string_view, const microfmt::sink &)
#else
#define MICROFMT_FORMATTER_INSTANCE(...)
#endif