emsdk/upstream/emscripten/system/lib/libcxx/src/fstream.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <__config>
#include <cstdio>
#include <fstream>

#if defined(_LIBCPP_WIN32API)
#  define WIN32_LEAN_AND_MEAN
#  define NOMINMAX
#  include <io.h>
#  include <windows.h>
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if defined(_LIBCPP_WIN32API)

// Confirm that `HANDLE` is `void*` as implemented in `basic_filebuf`
static_assert(std::same_as<HANDLE, void*>);

_LIBCPP_EXPORTED_FROM_ABI void* __filebuf_windows_native_handle(FILE* __file) noexcept {
  // https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/get-osfhandle?view=msvc-170
  intptr_t __handle = _get_osfhandle(fileno(__file));
  if (__handle == -1)
    return nullptr;
  return reinterpret_cast<void*>(__handle);
}

#endif

_LIBCPP_END_NAMESPACE_STD