zircon/kernel/lib/ktl/include/__config_site

// Copyright 2021 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#ifndef ZIRCON_KERNEL_LIB_KTL_INCLUDE___CONFIG_SITE_
#define ZIRCON_KERNEL_LIB_KTL_INCLUDE___CONFIG_SITE_

// The libc++ internal header <__config> does #include <__config_site> to get
// definitions that vary by operating system, machine, or configuration.  The
// toolchain's libc++ installation provides include/$triple/.../__config_site
// files for each $cpu-fuchsia appropriate for normal userland.  But the ktl
// abuse of libc++ is different from public userland libc++, so provide special
// kernel-appropriate definitions here.  This file will be in the include path
// ahead of any toolchain-supplied header.  Also, some special bare-metal build
// environments such as phys32 or efi that reuse ktl and kernel libc code may
// use settings that cause the compiler to change the $triple it injects into
// the include path to one for which no runtimes are built and so there is no
// __config_site file to be found at all.

// These two are what <__config_site> for Fuchsia userland defines.
#define _LIBCPP_ABI_VERSION 2
#define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS

// This tells the headers not to use `extern template` declarations that
// expect specific instantiations/specializations to come from the libc++
// library rather than the headers.  In the kernel, only the headers are
// ever going to be available.
#define _LIBCPP_DISABLE_EXTERN_TEMPLATE

// This tells <atomic> not to use threading APIs.
#define _LIBCPP_HAS_NO_PLATFORM_WAIT

// This tells <atomic> et al to use <__external_threading> instead
// of expecting either POSIX or C11 threading APIs.
#define _LIBCPP_HAS_THREAD_API_EXTERNAL
#define _LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL

#endif  // ZIRCON_KERNEL_LIB_KTL_INCLUDE___CONFIG_SITE_