From e47c381c62091d5d8583438b70632eecb96ad29e Mon Sep 17 00:00:00 2001
From: "Andrew M. Kuchling" <amk@amk.ca>
Date: Wed, 1 Sep 2004 14:04:51 +0000
Subject: [PATCH] [Bug #1011606] Only check file descriptors for exceptional
 conditions if the fd is readable or writable

---
 Lib/asyncore.py | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index f63a83eebad..a2387a1a82b 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -107,11 +107,14 @@ def poll(timeout=0.0, map=None):
     if map:
         r = []; w = []; e = []
         for fd, obj in map.items():
-            e.append(fd)
-            if obj.readable():
+            is_r = obj.readable()
+            is_w = obj.writable()
+            if is_r:
                 r.append(fd)
-            if obj.writable():
+            if is_w:
                 w.append(fd)
+            if is_r or is_w:
+                e.append(fd)
         if [] == r == w == e:
             time.sleep(timeout)
         else:
@@ -151,12 +154,15 @@ def poll2(timeout=0.0, map=None):
     pollster = select.poll()
     if map:
         for fd, obj in map.items():
-            flags = select.POLLERR | select.POLLHUP | select.POLLNVAL
+            flags = 0
             if obj.readable():
                 flags |= select.POLLIN | select.POLLPRI
             if obj.writable():
                 flags |= select.POLLOUT
             if flags:
+                # Only check for exceptions if object was either readable
+                # or writable.
+                flags |= select.POLLERR | select.POLLHUP | select.POLLNVAL
                 pollster.register(fd, flags)
         try:
             r = pollster.poll(timeout)