Re: Sockets, non-blocking connect and pool

From: Valentin Nechayev (netch_at_segfault.kiev.ua)
Date: 08/25/03

  • Next message: Måns Rullgård: "Re: What protects Unices from Virus like attacks ??" 
    Date: Mon, 25 Aug 2003 12:21:52 +0300

    >>> Miha Lesjak wrote:

    ML> I would like to know, how to get information about non-blocking
    ML> connect call; especially when is it finished and if it finished
    ML> successfully or not. I know I can do that with select, but that
    ML> is not what I am into. I would like to use the pool system call.

    ML> The problem is that I get POLLIN event as a result every time I
    ML> connect (even if I connect to a not reachable IP) and then the
    ML> call to recv fails (and there is where I handle connect error -
    ML> I have a variable to remember that the socket is in connecting
    ML> state).

    This is correct. POLLIN doesn't say read() or recv() will be successful.
    It only says it won't block (and, if is on nonblocking socket, will say
    something another than EAGAIN). This is design principle and this is
    correct design principle.
    For connect(), you should track socket state phase by yourself. Also,
    connection error diagnostics is provided by another tools: checking
    peer address (it isn't set unless connecting succeeded), quering asynchronous
    error code (setsockopt(s,SOL_SOCKET,SO_ERROR))...

    ML> How should I set the pollfd's events and what revents should I
    ML> expect after calling connect and then pool on my socket descriptor?
    s/pool/poll/
    your typo is systematic

    -netch-

  • Next message: Måns Rullgård: "Re: What protects Unices from Virus like attacks ??"

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