Cygwin/X: Make select() only poll and not block if there are unprocessed Windows messages

This is a workaround for select() sometimes not finding /dev/windows ready,
even if there are unprocessed Windows messages

1 files changed, 18 insertions, 0 deletions

diff --git a/hw/xwin/winblock.c b/hw/xwin/winblock.c
index 2965e9f3a..4362197b2 100644
--- a/hw/xwin/winblock.c
+++ b/hw/xwin/winblock.c
@@ -52,6 +52,24 @@ winBlockHandler (int nScreen,
     (*tvp)->tv_sec = 0;
     (*tvp)->tv_usec = 100;
   }
+#else
+  /*
+    Sometimes, we have work to do on the Windows message queue,
+    but /dev/windows doesn't appear to be ready.  At the moment,
+    I don't understand how that happens.
+
+    As a workaround, make sure select() just polls rather than
+    blocking if there are still messages to process...
+   */
+  if (GetQueueStatus(QS_ALLINPUT | QS_ALLPOSTMESSAGE) != 0)
+    {
+      struct timeval **tvp = pTimeout;
+      if (*tvp != NULL)
+        {
+          (*tvp)->tv_sec = 0;
+          (*tvp)->tv_usec = 0;
+        }
+    }
 #endif
 
 #if defined(XWIN_CLIPBOARD) || defined(XWIN_MULTIWINDOW)