在无数据的无阻塞套接字的情况下，recv将抛出socket.error异常，并且异常的值将具有EAGAIN或EWOULDBLOCK的错误号。例：
import sys
import socket
import fcntl, os
import errno
from time import sleep
s = socket.socket(socket.AF_INET, socket.soCK_STREAM)
s.connect(('127.0.0.1',9999))
fcntl.fcntl(s, fcntl.F_SETFL, os.O_NONBLOCK)
while True:
try:
msg = s.recv(4096)
except socket.error, e:
err = e.args[0]
if err == errno.EAGAIN or err == errno.EWOULDBLOCK:
sleep(1)
print 'No data available'
continue
else:
# a "real" error occurred
print e
sys.exit(1)
else:
# got a message, do something :)
在您通过socket.settimeout(n)或通过超时启用了非阻塞行为的情况下，情况有所不同socket.setblocking(False)。在这种情况下，仍会引发socket.error，但在超时的情况下，异常的伴随值始终是设置为“超时”的字符串。因此，要处理这种情况，您可以执行以下操作：
import sys
import socket
from time import sleep
s = socket.socket(socket.AF_INET, socket.soCK_STREAM)
s.connect(('127.0.0.1',9999))
s.settimeout(2)
while True:
try:
msg = s.recv(4096)
except socket.timeout, e:
err = e.args[0]
# this next if/else is a bit redundant, but illustrates how the
# timeout exception is setup
if err == 'timed out':
sleep(1)
print 'recv timed out, retry later'
continue
else:
print e
sys.exit(1)
except socket.error, e:
# Something else happened, handle error, exit, etc.
print e
sys.exit(1)
else:
if len(msg) == 0:
print 'orderly shutdown on server end'
sys.exit(0)
else:
# got a message do something :)
如评论中所述，这也是一种更可移植的解决方案，因为它不依赖于操作系统特定的功能来将套接字置于非阻塞模式。
有关更多详细信息，请参见recv（2）和python socket。
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