Xmobar.System.Utils, Xmobar.X11.Events

1 files changed, 36 insertions, 0 deletions

diff --git a/src/Xmobar/X11/Events.hs b/src/Xmobar/X11/Events.hs
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+------------------------------------------------------------------------------
+-- |
+-- Module: Xmobar.X11.Events
+-- Copyright: (c) 2018 Jose Antonio Ortega Ruiz
+-- License: BSD3-style (see LICENSE)
+--
+-- Maintainer: jao@gnu.org
+-- Stability: unstable
+-- Portability: portable
+-- Created: Sun Nov 25, 2018 23:24
+--
+--
+-- Utilities or event handling
+--
+------------------------------------------------------------------------------
+
+
+module Xmobar.X11.Events(nextEvent') where
+
+import Control.Concurrent
+import System.Posix.Types (Fd(..))
+
+import Graphics.X11.Xlib (
+  Display(..), XEventPtr, nextEvent, pending, connectionNumber)
+
+-- | A version of nextEvent that does not block in foreign calls.
+nextEvent' :: Display -> XEventPtr -> IO ()
+nextEvent' d p = do
+    pend <- pending d
+    if pend /= 0
+        then nextEvent d p
+        else do
+            threadWaitRead (Fd fd)
+            nextEvent' d p
+ where
+    fd = connectionNumber d