--- EV/README	2010/10/21 02:46:59	1.36
+++ EV/README	2010/10/23 22:25:44	1.37
@@ -77,6 +77,36 @@
     and still be faster than with any other event loop currently supported
     in Perl.
 
+  PORTING FROM EV 3.X to 4.X
+    EV version 4 introduces a number of incompatible changes summarised
+    here. According to the depreciation strategy used by libev, there is a
+    compatibility layer in place so programs should continue to run
+    unchanged (the XS interface lacks this layer, so programs using that one
+    need to be updated).
+
+    This compatibility layer will be switched off in some future release.
+
+    All changes relevant to Perl are renames of symbols, functions and
+    methods:
+
+      EV::loop          => EV::run
+      EV::LOOP_NONBLOCK => EV::RUN_NOWAIT
+      EV::LOOP_ONESHOT  => EV::RUN_ONCE
+
+      EV::unloop        => EV::break
+      EV::UNLOOP_CANCEL => EV::BREAK_CANCEL
+      EV::UNLOOP_ONE    => EV::BREAK_ONE
+      EV::UNLOOP_ALL    => EV::BREAK_ALL
+
+      EV::TIMEOUT       => EV::TIMER
+
+      EV::loop_count    => EV::iteration
+      EV::loop_depth    => EV::depth
+      EV::loop_verify   => EV::verify
+
+    The loop object methods corresponding to the functions above have been
+    similarly renamed.
+
   MODULE EXPORTS
     This module does not export any symbols.
 
@@ -768,7 +798,7 @@
         has gathered events), but before any other callbacks have been
         invoked.
 
-        This is used to integrate other event-based software into the EV
+        This can be used to integrate other event-based software into the EV
         mainloop: You register a prepare callback and in there, you create
         io and timer watchers as required by the other software. Here is a
         real-world example of integrating Net::SNMP (with some details left
@@ -815,6 +845,15 @@
         The "check_ns" variant doesn't start (activate) the newly created
         watcher.
 
+    EV::CHECK constant issues
+        Like all other watcher types, there is a bitmask constant for use in
+        $revents and other places. The "EV::CHECK" is special as it has the
+        same name as the "CHECK" sub called by Perl. This doesn't cause big
+        issues on newer perls (beginning with 5.8.9), but it means thatthe
+        constant must be *inlined*, i.e. runtime calls will not work. That
+        means that as long as you always "use EV" and then "EV::CHECK" you
+        are on the safe side.
+
    FORK WATCHERS - the audacity to resume the event loop after a fork
     Fork watchers are called when a "fork ()" was detected. The invocation
     is done before the event loop blocks next and before "check" watchers