diff --git a/include/boost/compat/detail/throw_system_error.hpp b/include/boost/compat/detail/throw_system_error.hpp
new file mode 100644
index 0000000..2f363e5
--- /dev/null
+++ b/include/boost/compat/detail/throw_system_error.hpp
@@ -0,0 +1,25 @@
+#ifndef BOOST_COMPAT_DETAIL_THROW_SYSTEM_ERROR_HPP_INCLUDED
+#define BOOST_COMPAT_DETAIL_THROW_SYSTEM_ERROR_HPP_INCLUDED
+
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/throw_exception.hpp>
+#include <boost/config.hpp>
+#include <system_error>
+
+namespace boost {
+namespace compat {
+namespace detail {
+
+BOOST_NORETURN BOOST_NOINLINE inline void throw_system_error( std::errc e, boost::source_location const& loc = BOOST_CURRENT_LOCATION )
+{
+    boost::throw_exception( std::system_error( std::make_error_code( e ) ), loc );
+}
+
+} // namespace detail
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_DETAIL_THROW_SYSTEM_ERROR_HPP_INCLUDED
diff --git a/include/boost/compat/shared_lock.hpp b/include/boost/compat/shared_lock.hpp
index 91edaa8..cf6ed72 100644
--- a/include/boost/compat/shared_lock.hpp
+++ b/include/boost/compat/shared_lock.hpp
@@ -5,12 +5,11 @@
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
-#include <boost/throw_exception.hpp>
-#include <boost/config.hpp>
+#include <boost/compat/detail/throw_system_error.hpp>
 
-#include <memory>
-#include <mutex>
-#include <system_error>
+#include <memory> // std::addressof
+#include <mutex> // std::defer_lock_t
+#include <system_error> // std::errc
 
 namespace boost {
 namespace compat {
@@ -21,14 +20,6 @@ class shared_lock;
 template <class Mutex>
 void swap( shared_lock<Mutex>& x, shared_lock<Mutex>& y ) noexcept;
 
-namespace detail {
-
-BOOST_NORETURN BOOST_NOINLINE inline void
-throw_system_error( std::errc e, boost::source_location const& loc = BOOST_CURRENT_LOCATION ) {
-  boost::throw_exception( std::system_error( std::make_error_code( e ) ), loc );
-}
-} // namespace detail
-
 template <class Mutex>
 class shared_lock {
 private: