Python 什么是全局默认超时
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What is the global default timeout
提问by user3139774
Python 3.4 . Trying to find what is the default timeout in urllib.request.urlopen() .
蟒蛇 3.4 。试图找到 urllib.request.urlopen() 中的默认超时时间。
Its signature is: urllib.request.urlopen(url, data=None, [timeout, ]*, cafile=None, capath=None, cadefault=False, context=None)
它的签名是： urllib.request.urlopen(url, data=None, [timeout, ]*, cafile=None, capath=None, cadefault=False, context=None)
The docsays that its "global default timeout", and looking at the code its: socket._GLOBAL_DEFAULT_TIMEOUT
该文档说它的“全局默认超时”，并查看其代码：socket._GLOBAL_DEFAULT_TIMEOUT
Still what is the actual value in secs?
仍然以秒为单位的实际值是多少？
采纳答案by Kevin
I suspect this is implementation-dependent. That said, for CPython:
我怀疑这是依赖于实现的。也就是说，对于 CPython：
From socket.create_connection,
If no timeoutis supplied, the global default timeout setting returned by :func:
getdefaulttimeoutis used.
如果没有超时供应，全局默认超时设置返回由：FUNC：
getdefaulttimeout使用。
From socketmodule.c,
static PyObject *
socket_getdefaulttimeout(PyObject *self)
{
if (defaulttimeout < 0.0) {
Py_INCREF(Py_None);
return Py_None;
}
else
return PyFloat_FromDouble(defaulttimeout);
}
Earlierin the same file,
在同一个文件的前面，
static double defaulttimeout = -1.0; /* Default timeout for new sockets */
So it looks like Py_None, aka None, is the default timeout. In other words, urlopennever times out. At least not from the Python end. I guess a timeout can still occur if the networking functions supplied by the OS have timeouts themselves.
所以看起来Py_None，又名None，是默认超时。换句话说，urlopen永远不会超时。至少不是来自 Python 端。我想如果操作系统提供的网络功能本身有超时，仍然会发生超时。
Edit: oops, I guess I didn't need to go source diving for the answer at all, since it's right there in the docs.
编辑：哎呀，我想我根本不需要去寻找答案的源头，因为它就在文档中。
A value of
Noneindicates that new socket objects have no timeout. When the socket module is first imported, the default isNone.
值
None表示新的套接字对象没有超时。首次导入 socket 模块时，默认为None.
