Extend handler tracking to cover reactor-related events.
diff --git a/asio/include/asio/detail/handler_tracking.hpp b/asio/include/asio/detail/handler_tracking.hpp
index e177f5f..bc5d5b8 100644
--- a/asio/include/asio/detail/handler_tracking.hpp
+++ b/asio/include/asio/detail/handler_tracking.hpp
@@ -44,8 +44,18 @@
 // - ASIO_HANDLER_INVOCATION_BEGIN(args)
 // - ASIO_HANDLER_INVOCATION_END
 // - ASIO_HANDLER_OPERATION(args)
+// - ASIO_HANDLER_REACTOR_REGISTRATION(args)
+// - ASIO_HANDLER_REACTOR_DEREGISTRATION(args)
+// - ASIO_HANDLER_REACTOR_READ_EVENT
+// - ASIO_HANDLER_REACTOR_WRITE_EVENT
+// - ASIO_HANDLER_REACTOR_ERROR_EVENT
+// - ASIO_HANDLER_REACTOR_EVENTS(args)
 // - ASIO_HANDLER_REACTOR_OPERATION(args)
 
+# if !defined(ASIO_ENABLE_HANDLER_TRACKING)
+#  define ASIO_ENABLE_HANDLER_TRACKING 1
+# endif /// !defined(ASIO_ENABLE_HANDLER_TRACKING)
+
 #elif defined(ASIO_ENABLE_HANDLER_TRACKING)
 
 class handler_tracking
@@ -122,6 +132,18 @@
       const char* object_type, void* object,
       uintmax_t native_handle, const char* op_name);
 
+  // Record that a descriptor has been registered with the reactor.
+  ASIO_DECL static void reactor_registration(execution_context& context,
+      uintmax_t native_handle, uintmax_t registration);
+
+  // Record that a descriptor has been deregistered from the reactor.
+  ASIO_DECL static void reactor_deregistration(execution_context& context,
+      uintmax_t native_handle, uintmax_t registration);
+
+  // Record a reactor-based operation that is associated with a handler.
+  ASIO_DECL static void reactor_events(execution_context& context,
+      uintmax_t registration, unsigned events);
+
   // Record a reactor-based operation that is associated with a handler.
   ASIO_DECL static void reactor_operation(
       const tracked_handler& h, const char* op_name,
@@ -164,6 +186,19 @@
 # define ASIO_HANDLER_OPERATION(args) \
   asio::detail::handler_tracking::operation args
 
+# define ASIO_HANDLER_REACTOR_REGISTRATION(args) \
+  asio::detail::handler_tracking::reactor_registration args
+
+# define ASIO_HANDLER_REACTOR_DEREGISTRATION(args) \
+  asio::detail::handler_tracking::reactor_deregistration args
+
+# define ASIO_HANDLER_REACTOR_READ_EVENT 1
+# define ASIO_HANDLER_REACTOR_WRITE_EVENT 2
+# define ASIO_HANDLER_REACTOR_ERROR_EVENT 4
+
+# define ASIO_HANDLER_REACTOR_EVENTS(args) \
+  asio::detail::handler_tracking::reactor_events args
+
 # define ASIO_HANDLER_REACTOR_OPERATION(args) \
   asio::detail::handler_tracking::reactor_operation args
 
@@ -177,6 +212,12 @@
 # define ASIO_HANDLER_INVOCATION_BEGIN(args) (void)0
 # define ASIO_HANDLER_INVOCATION_END (void)0
 # define ASIO_HANDLER_OPERATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_REGISTRATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_DEREGISTRATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_READ_EVENT 0
+# define ASIO_HANDLER_REACTOR_WRITE_EVENT 0
+# define ASIO_HANDLER_REACTOR_ERROR_EVENT 0
+# define ASIO_HANDLER_REACTOR_EVENTS(args) (void)0
 # define ASIO_HANDLER_REACTOR_OPERATION(args) (void)0
 
 #endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
diff --git a/asio/include/asio/detail/impl/epoll_reactor.ipp b/asio/include/asio/detail/impl/epoll_reactor.ipp
index 4cdef35..a2ddae4 100644
--- a/asio/include/asio/detail/impl/epoll_reactor.ipp
+++ b/asio/include/asio/detail/impl/epoll_reactor.ipp
@@ -150,6 +150,10 @@
 {
   descriptor_data = allocate_descriptor_state();
 
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
   {
     mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
 
@@ -175,6 +179,10 @@
 {
   descriptor_data = allocate_descriptor_state();
 
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
   {
     mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
 
@@ -335,6 +343,10 @@
 
     descriptor_lock.unlock();
 
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
     free_descriptor_state(descriptor_data);
     descriptor_data = 0;
 
@@ -364,6 +376,10 @@
 
     descriptor_lock.unlock();
 
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
     free_descriptor_state(descriptor_data);
     descriptor_data = 0;
   }
@@ -391,6 +407,35 @@
   epoll_event events[128];
   int num_events = epoll_wait(epoll_fd_, events, 128, timeout);
 
+#if defined(ASIO_ENABLE_HANDLER_TRACKING)
+  // Trace the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = events[i].data.ptr;
+    if (ptr == &interrupter_)
+    {
+      // Ignore.
+    }
+# if defined(ASIO_HAS_TIMERFD)
+    else if (ptr == &timer_fd_)
+    {
+      // Ignore.
+    }
+# endif // defined(ASIO_HAS_TIMERFD)
+    {
+      unsigned event_mask = 0;
+      if ((events[i].events & EPOLLIN) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_READ_EVENT;
+      if ((events[i].events & EPOLLOUT))
+        event_mask |= ASIO_HANDLER_REACTOR_WRITE_EVENT;
+      if ((events[i].events & (EPOLLERR | EPOLLHUP)) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_ERROR_EVENT;
+      ASIO_HANDLER_REACTOR_EVENTS((context(),
+            reinterpret_cast<uintmax_t>(ptr), event_mask));
+    }
+  }
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
 #if defined(ASIO_HAS_TIMERFD)
   bool check_timers = (timer_fd_ == -1);
 #else // defined(ASIO_HAS_TIMERFD)
diff --git a/asio/include/asio/detail/impl/handler_tracking.ipp b/asio/include/asio/detail/impl/handler_tracking.ipp
index 37a4f92..e838a93 100644
--- a/asio/include/asio/detail/impl/handler_tracking.ipp
+++ b/asio/include/asio/detail/impl/handler_tracking.ipp
@@ -280,6 +280,21 @@
       current_id, object_type, object, op_name);
 }
 
+void handler_tracking::reactor_registration(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, uintmax_t /*registration*/)
+{
+}
+
+void handler_tracking::reactor_deregistration(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, uintmax_t /*registration*/)
+{
+}
+
+void handler_tracking::reactor_events(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, unsigned /*events*/)
+{
+}
+
 void handler_tracking::reactor_operation(
     const tracked_handler& h, const char* op_name,
     const asio::error_code& ec)
diff --git a/asio/include/asio/detail/impl/kqueue_reactor.ipp b/asio/include/asio/detail/impl/kqueue_reactor.ipp
index 52127de..b92096e 100644
--- a/asio/include/asio/detail/impl/kqueue_reactor.ipp
+++ b/asio/include/asio/detail/impl/kqueue_reactor.ipp
@@ -137,6 +137,10 @@
 {
   descriptor_data = allocate_descriptor_state();
 
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
   mutex::scoped_lock lock(descriptor_data->mutex_);
 
   descriptor_data->descriptor_ = descriptor;
@@ -152,6 +156,10 @@
 {
   descriptor_data = allocate_descriptor_state();
 
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
   mutex::scoped_lock lock(descriptor_data->mutex_);
 
   descriptor_data->descriptor_ = descriptor;
@@ -313,6 +321,10 @@
 
     descriptor_lock.unlock();
 
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
     free_descriptor_state(descriptor_data);
     descriptor_data = 0;
 
@@ -346,6 +358,10 @@
 
     descriptor_lock.unlock();
 
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
     free_descriptor_state(descriptor_data);
     descriptor_data = 0;
   }
@@ -365,6 +381,31 @@
   struct kevent events[128];
   int num_events = kevent(kqueue_fd_, 0, 0, events, 128, timeout);
 
+#if defined(ASIO_ENABLE_HANDLER_TRACKING)
+  // Trace the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = reinterpret_cast<void*>(events[i].udata);
+    if (ptr != &interrupter_)
+    {
+      unsigned event_mask = 0;
+      switch (events[i].filter)
+      {
+      case EVFILT_READ:
+        event_mask |= ASIO_HANDLER_REACTOR_READ_EVENT;
+        break;
+      case EVFILT_WRITE:
+        event_mask |= ASIO_HANDLER_REACTOR_WRITE_EVENT;
+        break;
+      }
+      if ((events[i].flags & (EV_ERROR | EV_OOBAND)) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_ERROR_EVENT;
+      ASIO_HANDLER_REACTOR_EVENTS((context(),
+            reinterpret_cast<uintmax_t>(ptr), event_mask));
+    }
+  }
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
   // Dispatch the waiting events.
   for (int i = 0; i < num_events; ++i)
   {
diff --git a/asio/src/examples/cpp11/Makefile.am b/asio/src/examples/cpp11/Makefile.am
index 7e2c200..28b61b3 100644
--- a/asio/src/examples/cpp11/Makefile.am
+++ b/asio/src/examples/cpp11/Makefile.am
@@ -77,6 +77,7 @@
 endif
 
 EXTRA_DIST = \
+	handler_tracking/custom_tracking.hpp \
 	http/server/connection.hpp \
 	http/server/connection_manager.hpp \
 	http/server/header.hpp \
diff --git a/asio/src/examples/cpp11/handler_tracking/custom_tracking.hpp b/asio/src/examples/cpp11/handler_tracking/custom_tracking.hpp
new file mode 100644
index 0000000..d9cad58
--- /dev/null
+++ b/asio/src/examples/cpp11/handler_tracking/custom_tracking.hpp
@@ -0,0 +1,201 @@
+//
+// custom_tracking.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef CUSTOM_TRACKING_HPP
+#define CUSTOM_TRACKING_HPP
+
+#include <cinttypes>
+#include <cstdint>
+#include <cstdio>
+
+# define ASIO_INHERIT_TRACKED_HANDLER \
+  : public ::custom_tracking::tracked_handler
+
+# define ASIO_ALSO_INHERIT_TRACKED_HANDLER \
+  , public ::custom_tracking::tracked_handler
+
+# define ASIO_HANDLER_TRACKING_INIT \
+  ::custom_tracking::init()
+
+# define ASIO_HANDLER_CREATION(args) \
+  ::custom_tracking::creation args
+
+# define ASIO_HANDLER_COMPLETION(args) \
+  ::custom_tracking::completion tracked_completion args
+
+# define ASIO_HANDLER_INVOCATION_BEGIN(args) \
+  tracked_completion.invocation_begin args
+
+# define ASIO_HANDLER_INVOCATION_END \
+  tracked_completion.invocation_end()
+
+# define ASIO_HANDLER_OPERATION(args) \
+  ::custom_tracking::operation args
+
+# define ASIO_HANDLER_REACTOR_REGISTRATION(args) \
+  ::custom_tracking::reactor_registration args
+
+# define ASIO_HANDLER_REACTOR_DEREGISTRATION(args) \
+  ::custom_tracking::reactor_deregistration args
+
+# define ASIO_HANDLER_REACTOR_READ_EVENT 1
+# define ASIO_HANDLER_REACTOR_WRITE_EVENT 2
+# define ASIO_HANDLER_REACTOR_ERROR_EVENT 4
+
+# define ASIO_HANDLER_REACTOR_EVENTS(args) \
+  ::custom_tracking::reactor_events args
+
+# define ASIO_HANDLER_REACTOR_OPERATION(args) \
+  ::custom_tracking::reactor_operation args
+
+struct custom_tracking
+{
+  // Base class for objects containing tracked handlers.
+  struct tracked_handler
+  {
+    std::uintmax_t handler_id_ = 0; // To uniquely identify a handler.
+    std::uintmax_t tree_id_ = 0; // To identify related handlers.
+    const char* object_type_; // The object type associated with the handler.
+    std::uintmax_t native_handle_; // Native handle, if any.
+  };
+
+  // Initialise the tracking system.
+  static void init()
+  {
+  }
+
+  // Record the creation of a tracked handler.
+  static void creation(asio::execution_context& /*ctx*/, tracked_handler& h,
+      const char* object_type, void* /*object*/,
+      std::uintmax_t native_handle, const char* op_name)
+  {
+    // Generate a unique id for the new handler.
+    static std::atomic<std::uintmax_t> next_handler_id{1};
+    h.handler_id_ = next_handler_id++;
+
+    // Copy the tree identifier forward from the current handler.
+    if (*current_completion())
+      h.tree_id_ = (*current_completion())->handler_.tree_id_;
+
+    // Store various attributes of the operation to use in later output.
+    h.object_type_ = object_type;
+    h.native_handle_ = native_handle;
+
+    std::printf(
+        "Starting operation %s.%s for native_handle = %" PRIuMAX
+        ", handler = %" PRIuMAX ", tree = %" PRIuMAX "\n",
+        object_type, op_name, h.native_handle_, h.handler_id_, h.tree_id_);
+  }
+
+  struct completion
+  {
+    explicit completion(const tracked_handler& h)
+      : handler_(h),
+        next_(*current_completion())
+    {
+      *current_completion() = this;
+    }
+
+    completion(const completion&) = delete;
+    completion& operator=(const completion&) = delete;
+
+    // Destructor records only when an exception is thrown from the handler, or
+    // if the memory is being freed without the handler having been invoked.
+    ~completion()
+    {
+      *current_completion() = next_;
+    }
+
+    // Records that handler is to be invoked with the specified arguments.
+    template <class... Args>
+    void invocation_begin(Args&&... /*args*/)
+    {
+      std::printf("Entering handler %" PRIuMAX " in tree %" PRIuMAX "\n",
+          handler_.handler_id_, handler_.tree_id_);
+    }
+
+    // Record that handler invocation has ended.
+    void invocation_end()
+    {
+      std::printf("Leaving handler %" PRIuMAX " in tree %" PRIuMAX "\n",
+          handler_.handler_id_, handler_.tree_id_);
+    }
+
+    tracked_handler handler_;
+
+    // Completions may nest. Here we stash a pointer to the outer completion.
+    completion* next_;
+  };
+
+  static completion** current_completion()
+  {
+    static ASIO_THREAD_KEYWORD completion* current = nullptr;
+    return &current;
+  }
+
+  // Record an operation that is not directly associated with a handler.
+  static void operation(asio::execution_context& /*ctx*/,
+      const char* /*object_type*/, void* /*object*/,
+      std::uintmax_t /*native_handle*/, const char* /*op_name*/)
+  {
+  }
+
+  // Record that a descriptor has been registered with the reactor.
+  static void reactor_registration(asio::execution_context& context,
+      uintmax_t native_handle, uintmax_t registration)
+  {
+    std::printf("Adding to reactor native_handle = %" PRIuMAX
+        ", registration = %" PRIuMAX "\n", native_handle, registration);
+  }
+
+  // Record that a descriptor has been deregistered from the reactor.
+  static void reactor_deregistration(asio::execution_context& context,
+      uintmax_t native_handle, uintmax_t registration)
+  {
+    std::printf("Removing from reactor native_handle = %" PRIuMAX
+        ", registration = %" PRIuMAX "\n", native_handle, registration);
+  }
+
+  // Record reactor-based readiness events associated with a descriptor.
+  static void reactor_events(asio::execution_context& context,
+      uintmax_t registration, unsigned events)
+  {
+    std::printf(
+        "Reactor readiness for registration = %" PRIuMAX ", events =%s%s%s\n",
+        registration,
+        (events & ASIO_HANDLER_REACTOR_READ_EVENT) ? " read" : "",
+        (events & ASIO_HANDLER_REACTOR_WRITE_EVENT) ? " write" : "",
+        (events & ASIO_HANDLER_REACTOR_ERROR_EVENT) ? " error" : "");
+  }
+
+  // Record a reactor-based operation that is associated with a handler.
+  static void reactor_operation(const tracked_handler& h,
+      const char* op_name, const asio::error_code& ec)
+  {
+    std::printf(
+        "Performed operation %s.%s for native_handle = %" PRIuMAX
+        ", ec = %s:%d\n", h.object_type_, op_name, h.native_handle_,
+        ec.category().name(), ec.value());
+  }
+
+  // Record a reactor-based operation that is associated with a handler.
+  static void reactor_operation(const tracked_handler& h,
+      const char* op_name, const asio::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    std::printf(
+        "Performed operation %s.%s for native_handle = %" PRIuMAX
+        ", ec = %s:%d, n = %" PRIuMAX "\n", h.object_type_, op_name,
+        h.native_handle_, ec.category().name(), ec.value(),
+        static_cast<uintmax_t>(bytes_transferred));
+  }
+};
+
+#endif // CUSTOM_TRACKING_HPP