[WT-support] Network problem, explosion of duplicates

[Peter Stuge]

Tõnno Vähk wrote:
> What causes the UDP packets 10035 (?) error,

I can't say about that.


> what does that mean?

But 10035 is WSAEWOULDBLOCK, which means that the application is
calling winsock to perform some operation, e.g. receive data, on
a socket which has been set to non-blocking mode, and that if the
socket *had not* been set to non-blocking mode then winsock would
block - ie. not return immediately - e.g. because no data has been
sent to the network address and port associated with the socket.

The error can happen for many socket operation, not just receiving
data. I only used that as an example to explain the error.

An application showing WSAEWOULDBLOCK to a user typically means that
the programer has not quite finished some part of the program,
because sockets need to be set to non-blocking mode explicitly, and
thus all code which uses the socket must be able to take appropriate
action in case winsock returns this error code.

Using non-blocking IO is one common method for handling different
event sources (sockets, local user, files, ..) in a single code path.
The antithesis would be to use threads.


//Peter