id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
5756	read_some() with null_buffers blocks in non-blocking mode	Gennady Proskurin <gpr@…>	chris_kohlhoff	"I want to poll socket for readability (the same as calling POSIX poll or select with zero timeout), to just know if it is readable:
1. call sock.non_blocking(true)
2. call read_some with null_buffers()
3. it blocks

If I change null_buffers() to some read buffer, all works fine, would_block error is returned. The correct behaviour, I think, is to return immediately with corresponding error (no error if socket is readable, would_block if it is not).

At least tcp socket and posix::stream_descriptor are affected, not tested for other sockets. Also not tested write_some(), not sure if it is affected.

test program attached
"	Bugs	closed	To Be Determined	asio	Boost 1.47.0	Problem	fixed