In article <[EMAIL PROTECTED]>, mp <[EMAIL PROTECTED]> wrote:
> Thanks Roy. I was just trying to understand someone else's code, but > in the end it turns out that this was just a bug. > > What weirded me out was how injecting a print statement preventing the > error from occurring, but now I get it. Without blocking, the > connection handshake occurs in parallel after the connect_exc method > is called. In my example, my processor reaches the send call before > the connection manages to complete in the background. However, if you > stick in a print statement after the connect_exc call and before the > send call, it delays processing just long enough for the connection to > complete, thus no exception is thrown by the send call. I don't really understand that last part. There shouldn't be any background processing going on, unless there's a lot more code than you showed. The three-way handshake *can't* happen in the background, because connect_ex() has no way to know what value to return until the handshake is completed. Let's say I send a SYN, and 15 seconds later, you send a RST (indicating that the connection has been refused). The connect_ex() call has to have waited the 15 seconds for this to happen so it knows to return an appropriate error code. I do not understand why sticking a print statement in there should make any difference. -- http://mail.python.org/mailman/listinfo/python-list
