Re: PR_Poll() and non-blocking sockets?

On Tue, Jul 29, 2008 at 5:17 PM, Matt Lawson <[email protected]> wrote:
> Hi,
>
> I am attempting to use PR_Poll() in a server application to poll a collection of non-blocking sockets (which have been accepted using PR_Accept())  The problem is, no matter what I do, the call to PR_Poll() always returns immediately indicating the socket is readable.
>
> Is this the normal behavior?  Will PR_Poll() never pause for any length of time with non-blocking sockets?  I don't want to be hogging CPU at 100% if it's not necessary.
>
> I have searched for solutions online.  I have already been through the exercise of calling PR_GetConnectStatus() and PR_Poll() with write|exception to ensure that the socket gets fully established (and in fact this was part of the problem)
>
> So now I have an incoming PR_Accept()ed socket, which PR_GetConnectStatus() says is good, and I PR_Poll() it (with PR_POLL_READ) and it always returns true.
>
> This is all from the server's point of view.  All sockets including the bind/listen sockets are non-blocking.

PR_Poll works with non-blocking sockets.  In fact, PR_Poll
is intended to be used with non-blocking sockets.  PR_Poll
blocks until the events you're interested in have occurred.
The fact that the socket is in non-blocking mode affects
PR_Recv, PR_Send, etc., but doesn't affect PR_Poll.

PR_GetConnectStatus() should only be used with a non-blocking
socket on which a connect has just completed.  So you should
not call PR_GetConnectStatus() on an incoming PR_Accept()ed
socket.

Other than that, your description seems correct.  I'll need to look
at your code snippets to see what's wrong.

Wan-Teh