// file      : libbutl/ft/shared_mutex.hxx -*- C++ -*-
// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#ifndef LIBBUTL_FT_SHARED_MUTEX_HXX
#define LIBBUTL_FT_SHARED_MUTEX_HXX

#if defined(__clang__)
#  if __has_include(<__config>)
#    include <__config>          // _LIBCPP_VERSION
#  endif
#endif

// __cpp_lib_shared_mutex
//
#ifndef __cpp_lib_shared_mutex
   //
   // VC has it since 1900.
   //
#  if defined(_MSC_VER)
#    if _MSC_VER >= 1900
#      define __cpp_lib_shared_mutex 201505
#    endif
   //
   // Clang's libc++ seems to have it for a while (but not before 1200) so we
   // assume it's there from 1200. It's also only enabled after C++14. But not
   // for MacOS, where it is explicitly marked as unavailable until MacOS
   // 10.12.
   //
#  elif defined(_LIBCPP_VERSION) && defined(_LIBCPP_STD_VER)
#    if _LIBCPP_VERSION >= 1200 &&                              \
  _LIBCPP_STD_VER > 14 &&                                       \
  (!defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) ||   \
   __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101200)
#      define __cpp_lib_shared_mutex 201505
#    endif
   //
   // GCC libstdc++ has it since GCC 6 and it defines the feature test macro.
   // We will also use this for any other runtime.
   //
#  endif
#endif

// __cpp_lib_shared_timed_mutex
//
#ifndef __cpp_lib_shared_timed_mutex
   //
   // On MacOS shared_timed_mutex is marked as unavailable until MacOS
   // 10.12.
   //
#  if defined(_LIBCPP_VERSION)
#    if !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) ||      \
  __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101200
#      define __cpp_lib_shared_timed_mutex 201402
#    endif
#  else
#    define __cpp_lib_shared_timed_mutex 201402
#  endif
#endif

#endif // LIBBUTL_FT_SHARED_MUTEX_HXX