diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf49fc24..8975da9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 * Tidy up MSVC CMake configuration
 * Make close_code a proper enum
 * Add flat_streambuf
+* Rename to BEAST_DOXYGEN
 
 --------------------------------------------------------------------------------
 
diff --git a/doc/source.dox b/doc/source.dox
index 624ab633..f4707c41 100644
--- a/doc/source.dox
+++ b/doc/source.dox
@@ -282,8 +282,7 @@ EXPAND_ONLY_PREDEF     = YES
 SEARCH_INCLUDES        = YES
 INCLUDE_PATH           = ../
 INCLUDE_FILE_PATTERNS  =
-PREDEFINED             = DOXYGEN \
-                         GENERATING_DOCS
+PREDEFINED             = BEAST_DOXYGEN
 EXPAND_AS_DEFINED      =
 SKIP_FUNCTION_MACROS   = YES
 
diff --git a/extras/beast/doc_debug.hpp b/extras/beast/doc_debug.hpp
index 5b5587f0..7023c8a2 100644
--- a/extras/beast/doc_debug.hpp
+++ b/extras/beast/doc_debug.hpp
@@ -10,7 +10,7 @@
 
 namespace beast {
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 
 /// doc type (documentation debug helper)
 using doc_type = int;
diff --git a/extras/beast/test/yield_to.hpp b/extras/beast/test/yield_to.hpp
index c6b3a867..16dea02d 100644
--- a/extras/beast/test/yield_to.hpp
+++ b/extras/beast/test/yield_to.hpp
@@ -79,7 +79,7 @@ public:
 
         @param args Optional arguments forwarded to the callable object.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class F, class... Args>
     void
     yield_to(F&& f, Args&&... args);
diff --git a/include/beast/core/bind_handler.hpp b/include/beast/core/bind_handler.hpp
index 1b2d11da..18c26520 100644
--- a/include/beast/core/bind_handler.hpp
+++ b/include/beast/core/bind_handler.hpp
@@ -50,7 +50,7 @@ namespace beast {
     arguments are forwarded into the returned object.
 */
 template<class Handler, class... Args>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 implementation_defined
 #else
 detail::bound_handler<
diff --git a/include/beast/core/buffer_cat.hpp b/include/beast/core/buffer_cat.hpp
index a0c892a7..c2ab78ee 100644
--- a/include/beast/core/buffer_cat.hpp
+++ b/include/beast/core/buffer_cat.hpp
@@ -37,7 +37,7 @@ namespace beast {
     also a @b MutableBufferSequence, else the returned buffer sequence
     will be a @b ConstBufferSequence.
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 template<class... BufferSequence>
 implementation_defined
 buffer_cat(BufferSequence const&... buffers)
diff --git a/include/beast/core/buffer_concepts.hpp b/include/beast/core/buffer_concepts.hpp
index 545689eb..aeef682f 100644
--- a/include/beast/core/buffer_concepts.hpp
+++ b/include/beast/core/buffer_concepts.hpp
@@ -17,7 +17,7 @@ namespace beast {
 
 /// Determine if `T` meets the requirements of @b `BufferSequence`.
 template<class T, class BufferType>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_BufferSequence : std::integral_constant<bool, ...>
 #else
 struct is_BufferSequence : detail::is_BufferSequence<T, BufferType>::type
@@ -27,7 +27,7 @@ struct is_BufferSequence : detail::is_BufferSequence<T, BufferType>::type
 
 /// Determine if `T` meets the requirements of @b `ConstBufferSequence`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_ConstBufferSequence : std::integral_constant<bool, ...>
 #else
 struct is_ConstBufferSequence :
@@ -38,7 +38,7 @@ struct is_ConstBufferSequence :
 
 /// Determine if `T` meets the requirements of @b `DynamicBuffer`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_DynamicBuffer : std::integral_constant<bool, ...>
 #else
 struct is_DynamicBuffer : detail::is_DynamicBuffer<T>::type
@@ -48,7 +48,7 @@ struct is_DynamicBuffer : detail::is_DynamicBuffer<T>::type
 
 /// Determine if `T` meets the requirements of @b `MutableBufferSequence`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_MutableBufferSequence : std::integral_constant<bool, ...>
 #else
 struct is_MutableBufferSequence :
diff --git a/include/beast/core/buffers_adapter.hpp b/include/beast/core/buffers_adapter.hpp
index 36220d05..df9edf70 100644
--- a/include/beast/core/buffers_adapter.hpp
+++ b/include/beast/core/buffers_adapter.hpp
@@ -64,7 +64,7 @@ class buffers_adapter
     }
 
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type used to represent the input sequence as a list of buffers.
     using const_buffers_type = implementation_defined;
 
diff --git a/include/beast/core/consuming_buffers.hpp b/include/beast/core/consuming_buffers.hpp
index 4d8d42a6..2e09a418 100644
--- a/include/beast/core/consuming_buffers.hpp
+++ b/include/beast/core/consuming_buffers.hpp
@@ -59,7 +59,7 @@ public:
         `boost::asio::mutable_buffer`, else this type will be
         `boost::asio::const_buffer`.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using value_type = ...;
 #else
     using value_type = typename std::conditional<
@@ -70,7 +70,7 @@ public:
                         boost::asio::const_buffer>::type;
 #endif
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// A bidirectional iterator type that may be used to read elements.
     using const_iterator = implementation_defined;
 
diff --git a/include/beast/core/detail/prepare_buffers.hpp b/include/beast/core/detail/prepare_buffers.hpp
index 4f9441c9..040e087f 100644
--- a/include/beast/core/detail/prepare_buffers.hpp
+++ b/include/beast/core/detail/prepare_buffers.hpp
@@ -61,7 +61,7 @@ public:
                     boost::asio::mutable_buffer,
                         boost::asio::const_buffer>::type;
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// A bidirectional iterator type that may be used to read elements.
     using const_iterator = implementation_defined;
 
diff --git a/include/beast/core/dynabuf_readstream.hpp b/include/beast/core/dynabuf_readstream.hpp
index e914d434..e749ba01 100644
--- a/include/beast/core/dynabuf_readstream.hpp
+++ b/include/beast/core/dynabuf_readstream.hpp
@@ -110,7 +110,7 @@ public:
 
     /// The type of the lowest layer.
     using lowest_layer_type =
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
         implementation_defined;
 #else
         typename detail::get_lowest_layer<
@@ -272,7 +272,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class MutableBufferSequence, class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<ReadHandler, void(error_code)>::result_type
@@ -347,7 +347,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class ConstBufferSequence, class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<WriteHandler, void(error_code)>::result_type
diff --git a/include/beast/core/error.hpp b/include/beast/core/error.hpp
index b8c78687..0b9b667e 100644
--- a/include/beast/core/error.hpp
+++ b/include/beast/core/error.hpp
@@ -24,7 +24,7 @@ using system_error = boost::system::system_error;
 using error_category = boost::system::error_category;
 
 /// A function to return the system error category used by the library
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 error_category const&
 system_category();
 #else
@@ -35,7 +35,7 @@ using boost::system::system_category;
 using error_condition = boost::system::error_condition;
 
 /// The set of constants used for cross-platform error codes
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 enum errc{};
 #else
 namespace errc = boost::system::errc;
diff --git a/include/beast/core/flat_streambuf.hpp b/include/beast/core/flat_streambuf.hpp
index 496adc00..bf6ed9a8 100644
--- a/include/beast/core/flat_streambuf.hpp
+++ b/include/beast/core/flat_streambuf.hpp
@@ -35,14 +35,14 @@ namespace beast {
 */
 template<class Allocator>
 class basic_flat_streambuf
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
     : private detail::empty_base_optimization<
         typename std::allocator_traits<Allocator>::
             template rebind_alloc<char>>
 #endif
 {
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type of allocator used.
     using allocator_type = Allocator;
 #else
diff --git a/include/beast/core/handler_alloc.hpp b/include/beast/core/handler_alloc.hpp
index 08a395c3..b110ec44 100644
--- a/include/beast/core/handler_alloc.hpp
+++ b/include/beast/core/handler_alloc.hpp
@@ -35,7 +35,7 @@ namespace beast {
     the handler is invoked or undefined behavior results. This behavior
     is described as the "deallocate before invocation" Asio guarantee.
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 template<class T, class Handler>
 class handler_alloc;
 #else
diff --git a/include/beast/core/handler_concepts.hpp b/include/beast/core/handler_concepts.hpp
index e118072a..0f4fd9f2 100644
--- a/include/beast/core/handler_concepts.hpp
+++ b/include/beast/core/handler_concepts.hpp
@@ -16,7 +16,7 @@ namespace beast {
 
 /// Determine if `T` meets the requirements of @b `CompletionHandler`.
 template<class T, class Signature>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using is_CompletionHandler = std::integral_constant<bool, ...>;
 #else
 using is_CompletionHandler = std::integral_constant<bool,
diff --git a/include/beast/core/prepare_buffers.hpp b/include/beast/core/prepare_buffers.hpp
index 7db31b5b..0a960ea8 100644
--- a/include/beast/core/prepare_buffers.hpp
+++ b/include/beast/core/prepare_buffers.hpp
@@ -37,7 +37,7 @@ namespace beast {
     memory is not transferred.
 */
 template<class BufferSequence>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 implementation_defined
 #else
 inline
diff --git a/include/beast/core/static_streambuf.hpp b/include/beast/core/static_streambuf.hpp
index 75ced50a..2a0d49e1 100644
--- a/include/beast/core/static_streambuf.hpp
+++ b/include/beast/core/static_streambuf.hpp
@@ -28,7 +28,7 @@ namespace beast {
 */
 class static_streambuf
 {
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #else
 protected:
@@ -40,7 +40,7 @@ protected:
     std::uint8_t* end_;
 
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type used to represent the input sequence as a list of buffers.
     using const_buffers_type = implementation_defined;
 
@@ -116,7 +116,7 @@ public:
         in_ += std::min<std::size_t>(n, out_ - in_);
     }
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #else
 protected:
@@ -150,7 +150,7 @@ protected:
 template<std::size_t N>
 class static_streambuf_n
     : public static_streambuf
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
     , private boost::base_from_member<
         std::array<std::uint8_t, N>>
 #endif
@@ -158,14 +158,14 @@ class static_streambuf_n
     using member_type = boost::base_from_member<
         std::array<std::uint8_t, N>>;
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #endif
     static_streambuf_n(
         static_streambuf_n const&) = delete;
     static_streambuf_n& operator=(
         static_streambuf_n const&) = delete;
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 public:
 #endif
 
diff --git a/include/beast/core/stream_concepts.hpp b/include/beast/core/stream_concepts.hpp
index 5f0ba3ad..f3609e4b 100644
--- a/include/beast/core/stream_concepts.hpp
+++ b/include/beast/core/stream_concepts.hpp
@@ -16,7 +16,7 @@ namespace beast {
 
 /// Determine if `T` has the `get_io_service` member.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct has_get_io_service : std::integral_constant<bool, ...>{};
 #else
 using has_get_io_service = typename detail::has_get_io_service<T>::type;
@@ -24,7 +24,7 @@ using has_get_io_service = typename detail::has_get_io_service<T>::type;
 
 /// Determine if `T` meets the requirements of @b `AsyncReadStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_AsyncReadStream : std::integral_constant<bool, ...>{};
 #else
 using is_AsyncReadStream = typename detail::is_AsyncReadStream<T>::type;
@@ -32,7 +32,7 @@ using is_AsyncReadStream = typename detail::is_AsyncReadStream<T>::type;
 
 /// Determine if `T` meets the requirements of @b `AsyncWriteStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_AsyncWriteStream : std::integral_constant<bool, ...>{};
 #else
 using is_AsyncWriteStream = typename detail::is_AsyncWriteStream<T>::type;
@@ -40,7 +40,7 @@ using is_AsyncWriteStream = typename detail::is_AsyncWriteStream<T>::type;
 
 /// Determine if `T` meets the requirements of @b `SyncReadStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_SyncReadStream : std::integral_constant<bool, ...>{};
 #else
 using is_SyncReadStream = typename detail::is_SyncReadStream<T>::type;
@@ -48,7 +48,7 @@ using is_SyncReadStream = typename detail::is_SyncReadStream<T>::type;
 
 /// Determine if `T` meets the requirements of @b `SyncWriterStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_SyncWriteStream : std::integral_constant<bool, ...>{};
 #else
 using is_SyncWriteStream = typename detail::is_SyncWriteStream<T>::type;
@@ -56,7 +56,7 @@ using is_SyncWriteStream = typename detail::is_SyncWriteStream<T>::type;
 
 /// Determine if `T` meets the requirements of @b `AsyncStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_AsyncStream : std::integral_constant<bool, ...>{};
 #else
 using is_AsyncStream = std::integral_constant<bool,
@@ -65,7 +65,7 @@ using is_AsyncStream = std::integral_constant<bool,
 
 /// Determine if `T` meets the requirements of @b `SyncStream`.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_SyncStream : std::integral_constant<bool, ...>{};
 #else
 using is_SyncStream = std::integral_constant<bool,
diff --git a/include/beast/core/streambuf.hpp b/include/beast/core/streambuf.hpp
index 537094c1..ed0cae6d 100644
--- a/include/beast/core/streambuf.hpp
+++ b/include/beast/core/streambuf.hpp
@@ -32,14 +32,14 @@ namespace beast {
 */
 template<class Allocator>
 class basic_streambuf
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
     : private detail::empty_base_optimization<
         typename std::allocator_traits<Allocator>::
             template rebind_alloc<char>>
 #endif
 {
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type of allocator used.
     using allocator_type = Allocator;
 #else
@@ -81,7 +81,7 @@ private:
     size_type out_end_ = 0; // output end offset in list_.back()
 
 public:
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type used to represent the input sequence as a list of buffers.
     using const_buffers_type = implementation_defined;
 
diff --git a/include/beast/core/to_string.hpp b/include/beast/core/to_string.hpp
index e391ea2d..14d32589 100644
--- a/include/beast/core/to_string.hpp
+++ b/include/beast/core/to_string.hpp
@@ -29,7 +29,7 @@ namespace beast {
     the buffers parameter meets the requirements of @b `ConstBufferSequence`.
 */
 template<class ConstBufferSequence>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 std::string
 #else
 typename std::enable_if<
diff --git a/include/beast/core/write_dynabuf.hpp b/include/beast/core/write_dynabuf.hpp
index 646e7874..c91b984c 100644
--- a/include/beast/core/write_dynabuf.hpp
+++ b/include/beast/core/write_dynabuf.hpp
@@ -49,7 +49,7 @@ namespace beast {
     the `dynabuf` parameter meets the requirements of @b `DynamicBuffer`.
 */
 template<class DynamicBuffer, class... Args>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void
 #else
 typename std::enable_if<is_DynamicBuffer<DynamicBuffer>::value>::type
diff --git a/include/beast/http/basic_dynabuf_body.hpp b/include/beast/http/basic_dynabuf_body.hpp
index a2c09014..981905e8 100644
--- a/include/beast/http/basic_dynabuf_body.hpp
+++ b/include/beast/http/basic_dynabuf_body.hpp
@@ -27,7 +27,7 @@ struct basic_dynabuf_body
     /// The type of the `message::body` member
     using value_type = DynamicBuffer;
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #endif
 
diff --git a/include/beast/http/basic_fields.hpp b/include/beast/http/basic_fields.hpp
index 2589c827..f4f73ba9 100644
--- a/include/beast/http/basic_fields.hpp
+++ b/include/beast/http/basic_fields.hpp
@@ -39,7 +39,7 @@ namespace http {
 */
 template<class Allocator>
 class basic_fields :
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
     private beast::detail::empty_base_optimization<
         typename std::allocator_traits<Allocator>::
             template rebind_alloc<
@@ -89,17 +89,17 @@ public:
 
         Meets the requirements of @b Field.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using value_type = implementation_defined;
 #endif
 
     /// A const iterator to the field sequence
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using iterator = implementation_defined;
 #endif
 
     /// A const iterator to the field sequence
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using const_iterator = implementation_defined;
 #endif
 
diff --git a/include/beast/http/basic_parser_v1.hpp b/include/beast/http/basic_parser_v1.hpp
index cda14a00..3f03dff6 100644
--- a/include/beast/http/basic_parser_v1.hpp
+++ b/include/beast/http/basic_parser_v1.hpp
@@ -308,7 +308,7 @@ public:
 
         @param args One or more parser options to set.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class... Args>
     void
     set_option(Args&&... args)
@@ -449,7 +449,7 @@ public:
         @return The number of bytes consumed in the input sequence.
     */
     template<class ConstBufferSequence>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     std::size_t
 #else
     typename std::enable_if<
diff --git a/include/beast/http/chunk_encode.hpp b/include/beast/http/chunk_encode.hpp
index a437fe18..082d2df1 100644
--- a/include/beast/http/chunk_encode.hpp
+++ b/include/beast/http/chunk_encode.hpp
@@ -36,7 +36,7 @@ namespace http {
     @see <a href=https://tools.ietf.org/html/rfc7230#section-4.1.3>rfc7230 section 4.1.3</a>
 */
 template<class ConstBufferSequence>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 implementation_defined
 #else
 beast::detail::buffer_cat_helper<
@@ -59,7 +59,7 @@ chunk_encode(bool fin, ConstBufferSequence const& buffers)
     @see <a href=https://tools.ietf.org/html/rfc7230#section-4.1.3>rfc7230 section 4.1.3</a>
 */
 inline
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 implementation_defined
 #else
 boost::asio::const_buffers_1
diff --git a/include/beast/http/concepts.hpp b/include/beast/http/concepts.hpp
index 2e83fe7a..8dafa2ca 100644
--- a/include/beast/http/concepts.hpp
+++ b/include/beast/http/concepts.hpp
@@ -129,7 +129,7 @@ public:
 
 /// Determine if `T` meets the requirements of @b Body.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_Body : std::integral_constant<bool, ...>{};
 #else
 using is_Body = detail::has_value_type<T>;
@@ -140,7 +140,7 @@ using is_Body = detail::has_value_type<T>;
     @tparam T The type to check, which must meet the
     requirements of @b Body.
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 template<class T>
 struct has_reader : std::integral_constant<bool, ...>{};
 #else
@@ -158,7 +158,7 @@ struct has_reader<T, beast::detail::void_t<
     @tparam T The type to check, which must meet the
     requirements of @b Body.
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 template<class T>
 struct has_writer : std::integral_constant<bool, ...>{};
 #else
@@ -178,7 +178,7 @@ struct has_writer<T, beast::detail::void_t<
     @tparam M The message type to test with, which must be of
     type `message`.
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 template<class T, class M>
 struct is_Reader : std::integral_constant<bool, ...> {};
 #else
@@ -211,7 +211,7 @@ struct is_Reader<T, M, beast::detail::void_t<decltype(
     type `message`.
 */
 template<class T, class M>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_Writer : std::integral_constant<bool, ...> {};
 #else
 using is_Writer = typename detail::is_Writer<T, M>::type;
@@ -219,7 +219,7 @@ using is_Writer = typename detail::is_Writer<T, M>::type;
 
 /// Determine if `T` meets the requirements of @b Parser.
 template<class T>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 struct is_Parser : std::integral_constant<bool, ...>{};
 #else
 using is_Parser = typename detail::is_Parser<T>::type;
diff --git a/include/beast/http/empty_body.hpp b/include/beast/http/empty_body.hpp
index 40f549d9..2e61fb2a 100644
--- a/include/beast/http/empty_body.hpp
+++ b/include/beast/http/empty_body.hpp
@@ -25,14 +25,14 @@ namespace http {
 */
 struct empty_body
 {
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     /// The type of the `message::body` member
     using value_type = void;
 #else
     struct value_type {};
 #endif
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #endif
 
diff --git a/include/beast/http/header_parser_v1.hpp b/include/beast/http/header_parser_v1.hpp
index c6f732d2..555659ec 100644
--- a/include/beast/http/header_parser_v1.hpp
+++ b/include/beast/http/header_parser_v1.hpp
@@ -84,7 +84,7 @@ public:
 
         @param args Forwarded to the header constructor.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class... Args>
     explicit
     header_parser_v1(Args&&... args);
diff --git a/include/beast/http/message.hpp b/include/beast/http/message.hpp
index 70cfbf19..ae47d633 100644
--- a/include/beast/http/message.hpp
+++ b/include/beast/http/message.hpp
@@ -19,7 +19,7 @@
 namespace beast {
 namespace http {
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 /** A container for a HTTP request or response header.
 
     A header includes the Start Line and Fields.
@@ -44,7 +44,7 @@ struct header<true, Fields>
 #endif
 {
     /// Indicates if the header is a request or response.
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     static bool constexpr is_request = isRequest;
 
 #else
@@ -104,7 +104,7 @@ struct header<true, Fields>
         if and only if the first parameter is not convertible to
         `header`.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class... Args>
     explicit
     header(Args&&... args);
@@ -293,7 +293,7 @@ struct message : header<isRequest, Fields>
         only if `u` is not convertible to `base_type`.
     */
     template<class U
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
         , class = typename std::enable_if<
             ! std::is_convertible<typename
                 std::decay<U>::type, base_type>::value>::type
@@ -315,7 +315,7 @@ struct message : header<isRequest, Fields>
         only if `u` is not convertible to `base_type`.
     */
     template<class U, class V
-#if ! GENERATING_DOCS
+#if ! BEAST_DOXYGEN
         ,class = typename std::enable_if<! std::is_convertible<
             typename std::decay<U>::type, base_type>::value>::type
 #endif
@@ -388,7 +388,7 @@ private:
 
 //------------------------------------------------------------------------------
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 /** Swap two header objects.
 
     @par Requirements
diff --git a/include/beast/http/parse.hpp b/include/beast/http/parse.hpp
index bcc8b0f5..58065bfe 100644
--- a/include/beast/http/parse.hpp
+++ b/include/beast/http/parse.hpp
@@ -138,7 +138,7 @@ parse(SyncReadStream& stream,
 */
 template<class AsyncReadStream,
     class DynamicBuffer, class Parser, class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void_or_deduced
 #else
 typename async_completion<
diff --git a/include/beast/http/parser_v1.hpp b/include/beast/http/parser_v1.hpp
index be1aed1e..86c626b8 100644
--- a/include/beast/http/parser_v1.hpp
+++ b/include/beast/http/parser_v1.hpp
@@ -116,7 +116,7 @@ public:
         @note This function participates in overload resolution only
         if the first argument is not a parser or fields parser.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class... Args>
     explicit
     parser_v1(Args&&... args);
diff --git a/include/beast/http/read.hpp b/include/beast/http/read.hpp
index 54dd5796..56cc4324 100644
--- a/include/beast/http/read.hpp
+++ b/include/beast/http/read.hpp
@@ -153,7 +153,7 @@ read(SyncReadStream& stream, DynamicBuffer& dynabuf,
 template<class AsyncReadStream, class DynamicBuffer,
     bool isRequest, class Body, class Fields,
         class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void_or_deduced
 #else
 typename async_completion<
@@ -285,7 +285,7 @@ read(SyncReadStream& stream, DynamicBuffer& dynabuf,
 template<class AsyncReadStream, class DynamicBuffer,
     bool isRequest, class Body, class Fields,
         class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void_or_deduced
 #else
 typename async_completion<
diff --git a/include/beast/http/rfc7230.hpp b/include/beast/http/rfc7230.hpp
index 1f73194d..4eca51e1 100644
--- a/include/beast/http/rfc7230.hpp
+++ b/include/beast/http/rfc7230.hpp
@@ -61,7 +61,7 @@ public:
         std::pair<boost::string_ref, boost::string_ref>;
 
     /// A constant iterator to the list
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using const_iterator = implementation_defined;
 #else
     class const_iterator;
@@ -150,7 +150,7 @@ public:
     using value_type = std::pair<boost::string_ref, param_list>;
 
     /// A constant iterator to the list
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using const_iterator = implementation_defined;
 #else
     class const_iterator;
@@ -238,7 +238,7 @@ public:
     using value_type = boost::string_ref;
 
     /// A constant iterator to the list
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     using const_iterator = implementation_defined;
 #else
     class const_iterator;
diff --git a/include/beast/http/string_body.hpp b/include/beast/http/string_body.hpp
index 707709c1..7f2e63a1 100644
--- a/include/beast/http/string_body.hpp
+++ b/include/beast/http/string_body.hpp
@@ -28,7 +28,7 @@ struct string_body
     /// The type of the `message::body` member
     using value_type = std::string;
 
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 private:
 #endif
 
diff --git a/include/beast/http/write.hpp b/include/beast/http/write.hpp
index b190e2e6..563a8690 100644
--- a/include/beast/http/write.hpp
+++ b/include/beast/http/write.hpp
@@ -121,7 +121,7 @@ write(SyncWriteStream& stream,
 template<class AsyncWriteStream,
     bool isRequest, class Fields,
         class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void_or_deduced
 #else
 typename async_completion<
@@ -240,7 +240,7 @@ write(SyncWriteStream& stream,
 template<class AsyncWriteStream,
     bool isRequest, class Body, class Fields,
         class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 void_or_deduced
 #else
 typename async_completion<
diff --git a/include/beast/websocket/option.hpp b/include/beast/websocket/option.hpp
index 005ae7b2..cdfe5037 100644
--- a/include/beast/websocket/option.hpp
+++ b/include/beast/websocket/option.hpp
@@ -44,7 +44,7 @@ namespace websocket {
     stream.set_option(auto_fragment{true});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using auto_fragment = implementation_defined;
 #else
 struct auto_fragment
@@ -103,7 +103,7 @@ struct auto_fragment
     ws.set_option(decorate(identity{}));
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using decorate = implementation_defined;
 #else
 using decorate = detail::decorator_type;
@@ -133,7 +133,7 @@ using decorate = detail::decorator_type;
     ws.set_option(keep_alive{8192});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using keep_alive = implementation_defined;
 #else
 struct keep_alive
@@ -169,7 +169,7 @@ struct keep_alive
     ws.set_option(message_type{opcode::binary});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using message_type = implementation_defined;
 #else
 struct message_type
@@ -270,7 +270,7 @@ struct permessage_deflate
           To remove the ping callback, construct the option with
           no parameters: `set_option(ping_callback{})`
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using ping_callback = implementation_defined;
 #else
 struct ping_callback
@@ -312,7 +312,7 @@ struct ping_callback
     ws.set_option(read_buffer_size{16 * 1024});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using read_buffer_size = implementation_defined;
 #else
 struct read_buffer_size
@@ -350,7 +350,7 @@ struct read_buffer_size
     ws.set_option(read_message_max{65536});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using read_message_max = implementation_defined;
 #else
 struct read_message_max
@@ -393,7 +393,7 @@ struct read_message_max
     ws.set_option(write_buffer_size{8192});
     @endcode
 */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
 using write_buffer_size = implementation_defined;
 #else
 struct write_buffer_size
diff --git a/include/beast/websocket/stream.hpp b/include/beast/websocket/stream.hpp
index 5f58042a..ccffa16e 100644
--- a/include/beast/websocket/stream.hpp
+++ b/include/beast/websocket/stream.hpp
@@ -96,7 +96,7 @@ public:
 
     /// The type of the lowest layer.
     using lowest_layer_type =
-    #if GENERATING_DOCS
+    #if BEAST_DOXYGEN
         implementation_defined;
     #else
         typename beast::detail::get_lowest_layer<
@@ -152,7 +152,7 @@ public:
 
         @param args One or more stream options to set.
     */
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     template<class... Args>
     void
     set_option(Args&&... args)
@@ -192,7 +192,7 @@ public:
         the version number is used.
     */
     void
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     set_option(implementation_defined o)
 #else
     set_option(detail::decorator_type const& o)
@@ -433,7 +433,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class AcceptHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -559,7 +559,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class ConstBufferSequence, class AcceptHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -676,7 +676,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class Body, class Fields, class AcceptHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -813,7 +813,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class HandshakeHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -924,7 +924,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class CloseHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1006,7 +1006,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1103,7 +1103,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1251,7 +1251,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class DynamicBuffer, class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1409,7 +1409,7 @@ public:
         manner equivalent to using boost::asio::io_service::post().
     */
     template<class DynamicBuffer, class ReadHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1535,7 +1535,7 @@ public:
         manner equivalent to using `boost::asio::io_service::post`.
     */
     template<class ConstBufferSequence, class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<
@@ -1651,7 +1651,7 @@ public:
         ); @endcode
     */
     template<class ConstBufferSequence, class WriteHandler>
-#if GENERATING_DOCS
+#if BEAST_DOXYGEN
     void_or_deduced
 #else
     typename async_completion<