diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,8 @@
+### 0.4.0.0
+
+- all asynchronous handlers can now report events via eventfd channels
+- new dependency on package *binary* (>= 0.8.1.0)
+
 ### 0.3.2.2
 
 - stricter constraints for packages *base* (>= 4.8 && < 5) and
diff --git a/NgxExport.hs b/NgxExport.hs
--- a/NgxExport.hs
+++ b/NgxExport.hs
@@ -54,6 +54,7 @@
 import qualified Data.ByteString.Unsafe as B
 import qualified Data.ByteString.Lazy as L
 import qualified Data.ByteString.Lazy.Char8 as C8L
+import           Data.Binary.Put
 import           Paths_ngx_export (version)
 import           Data.Version
 
@@ -178,8 +179,8 @@
 -- for using in directive /haskell_run_async/.
 ngxExportAsyncIOYY =
     ngxExportC 'IOYY 'asyncIOYY
-    [t|CString -> CInt ->
-       CInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
+    [t|CString -> CInt -> CInt -> CUInt -> CUInt ->
+       Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
 
 -- | Exports a function of type
 -- /'L.ByteString' -> 'B.ByteString' -> 'IO' 'L.ByteString'/
@@ -190,7 +191,7 @@
 ngxExportAsyncOnReqBody =
     ngxExport 'IOYYY 'asyncIOYYY
     [t|Ptr NgxStrType -> CInt -> CString -> CInt ->
-       CInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
+       CInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
 
 -- | Exports a function of type
 -- /'B.ByteString' -> 'Bool' -> 'IO' 'L.ByteString'/
@@ -200,8 +201,8 @@
 -- being run for the first time.
 ngxExportServiceIOYY =
     ngxExport 'IOYY 'asyncIOYY
-    [t|CString -> CInt ->
-       CInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
+    [t|CString -> CInt -> CInt -> CUInt -> CUInt ->
+       Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()|]
 
 -- | Exports a function of type
 -- /'B.ByteString' -> ('L.ByteString', 'String', 'Int')/
@@ -359,9 +360,15 @@
         `catch` \e -> return $ C8L.pack $ show (e :: SomeException)
     pokeLazyByteString s p
 
+asyncIOFlag1b :: B.ByteString
+asyncIOFlag1b = L.toStrict $ runPut $ putInt8 1
+
+asyncIOFlag8b :: B.ByteString
+asyncIOFlag8b = L.toStrict $ runPut $ putInt64host 1
+
 asyncIOCommon :: IO C8L.ByteString ->
-    CInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
-asyncIOCommon a (I fd) p pl r = void . async $
+    CInt -> Bool -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
+asyncIOCommon a (I fd) efd p pl r = void . async $
     ((Right <$> a)
         `catch` (\e -> return $ Left $ show (e :: SomeException)) >>=
             either
@@ -376,20 +383,29 @@
                     poke r 0
                 )
     )
-    `finally` ((fdWrite fd "0" >> closeFd fd) `catchIOError` const (return ()))
+    `finally`
+    ((if efd
+          then void $ B.unsafeUseAsCString asyncIOFlag8b
+                         (\(castPtr -> s) -> fdWriteBuf fd s 8)
+          else B.unsafeUseAsCString asyncIOFlag1b
+                         (\(castPtr -> s) -> fdWriteBuf fd s 1) >> closeFd fd
+     ) `catchIOError` const (return ())
+    )
 
 asyncIOYY :: NgxExport -> CString -> CInt ->
-    CInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
-asyncIOYY (IOYY f) x (I n) fd ((/= 0) -> fstRun) =
-    asyncIOCommon (B.unsafePackCStringLen (x, n) >>= flip f fstRun) fd
+    CInt -> CUInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
+asyncIOYY (IOYY f) x (I n) fd ((/= 0) -> efd) ((/= 0) -> fstRun) =
+    asyncIOCommon (B.unsafePackCStringLen (x, n) >>= flip f fstRun) fd efd
 
 asyncIOYYY :: NgxExport -> Ptr NgxStrType -> CInt -> CString -> CInt ->
-    CInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
-asyncIOYYY (IOYYY f) b (I m) x (I n) =
-    asyncIOCommon $ do
+    CInt -> CUInt -> Ptr CString -> Ptr CSize -> Ptr CUInt -> IO ()
+asyncIOYYY (IOYYY f) b (I m) x (I n) fd ((/= 0) -> efd) =
+    asyncIOCommon
+    (do
         b' <- peekNgxStringArrayLenY b m
         x' <- B.unsafePackCStringLen (x, n)
         f b' x'
+    ) fd efd
 
 bS :: NgxExport -> CString -> CInt -> IO CUInt
 bS (BS f) x (I n) =
diff --git a/ngx-export.cabal b/ngx-export.cabal
--- a/ngx-export.cabal
+++ b/ngx-export.cabal
@@ -1,5 +1,5 @@
 name:                ngx-export
-version:             0.3.2.2
+version:             0.4.0.0
 synopsis:            Helper module for Nginx haskell module
 description:         Helper module for
         <http://github.com/lyokha/nginx-haskell-module Nginx haskell module>
@@ -21,6 +21,7 @@
                      , bytestring >= 0.10.0.0
                      , unix
                      , async >= 2.0
+                     , binary >= 0.8.1.0
   exposed-modules:     NgxExport
   other-modules:       Paths_ngx_export