如何非阻塞地读取命名的FIFO？
如何非阻塞地读取命名的FIFO？
提问于 2013-01-16 03:59:07
我创建了一个先进先出，并定期从a.py以只读和非阻塞模式打开它：
os.mkfifo(cs_cmd_fifo_file, 0777)
io = os.open(fifo, os.O_RDONLY | os.O_NONBLOCK)
buffer = os.read(io, BUFFER_SIZE)在b.py中，打开先进先出以进行写入：
out = open(fifo, 'w')
out.write('sth')那么a.py会抛出一个错误：
buffer = os.read(io, BUFFER_SIZE)
OSError: [Errno 11] Resource temporarily unavailable有人知道哪里出问题了吗？
回答 2
Stack Overflow用户
回答已采纳
发布于 2013-01-16 04:02:42
根据read(2)的手册页
EAGAIN or EWOULDBLOCK The file descriptor fd refers to a socket and has been marked nonblocking (O\_NONBLOCK), and the read would block. POSIX.1-2001 allows either error to be returned for this case, and does not require these constants to have the same value, so a portable application should check for both possibilities.
因此，您得到的是没有可供读取的数据。像这样处理错误是安全的：
try:
buffer = os.read(io, BUFFER_SIZE)
except OSError as err:
if err.errno == errno.EAGAIN or err.errno == errno.EWOULDBLOCK:
buffer = None
else:
raise # something else has happened -- better reraise
if buffer is None:
# nothing was received -- do something else
else:
# buffer contains some received data -- do something with it确保导入了errno模块：import errno。
Stack Overflow用户
发布于 2013-01-16 04:07:32
out = open(fifo, 'w')谁来帮你结账？将您的open+write替换为：
with open(fifo, 'w') as fp:
fp.write('sth')更新：好的，那就这样吧：
out = os.open(fifo, os.O_NONBLOCK | os.O_WRONLY)
os.write(out, 'tetet')页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/14345816
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