Behavior of SocketImpl::receiveBytes in case of timeout

[nlw0]

I'm trying to understand the exact behavior intended for this function:

poco/Net/include/Poco/Net/SocketImpl.h

Lines 224 to 231 in 3f76ad6

	virtual int receiveBytes(Poco::Buffer<char>& buffer, int flags = 0, const Poco::Timespan& timeout = 100000);
	/// Receives data from the socket and stores it in the buffer.
	/// If needed, the buffer will be resized to accomodate the
	/// data. Note that this function may impose additional
	/// performance penalties due to the check for the available
	/// amount of data.
	///
	/// Returns the number of bytes received.

Does it simply return 0 in case of a timeout? Is it intended as a polling function?

Similar functions throw a TimeoutException in case of timeout, and this limit would be set by setReceiveTimeout. This method here takes a separate timeout parameter, though, with a default value, and it might seem at first that it would supersede the socket timeout attribute, but it's not exactly that. First of all, there's still a timeout test happening inside the function body. But like I mentioned before, the behavior seems to be returning 0 in case the parameter-passed timeout is reached.

Is this by design, should I make a patch to update the documentation?

And in this case, how would I obtain the behavior of receiving a TimeoutException if I'm using a Poco::Buffer<char>& instead of a SocketBufVec& or a void * buffer, int length to store the output? This seems like an inconsistent behavior depending only on the choice of the output data structure.