[Spread-users] Hangs in client in SP_multicast

John Lane Schultz jschultz at spreadconcepts.com
Tue Mar 18 12:22:15 EDT 2008

SP_multicast is a blocking function.  If the TCP/IP or pipe
connection from the client to daemon is full, then the connection
will block.

You can kind of use select() and ioctl() to try and detect this
condition and detect how many bytes can be written w/o blocking, but
currently the SP_ functions are not written to be non-blocking
right now.

It is not too difficult to write a non-blocking version, but this
work has not yet been done.


John Lane Schultz
Spread Concepts LLC
Phn: 443 838 2200 
Fax: 301 560 8875

Tuesday, March 18, 2008, 10:43:45 AM, you wrote:

> As far as I thought, SP_multicast was (almost) a non-blocking function. But,
> under heavy workload (system load is <1, on 8-CPU machine), SP_multicast
> hangs for even 15 seconds. Is this a bug or a feature?

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