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3.15 Call Unix select for data connections

Loadable Function: select_sockets (connections, timeout)
Loadable Function: select_sockets (connections, timeout, nfds)

Calls Unix select for data connections in a parallel cluster.

This function is for advanced usage (and therefore has minimal documentation), typically the programming of schedulers. It can be called at the client or at a server.

connections: valid connections object (see pconnect and pserver, possibly indexed).

timeout: seconds, negative for infinite.

nfds: Passed to Unix select as first argument, see documentation of Uix select. Default: FD_SETSIZE (platform specific).

An error is returned if nfds or a watched filedescriptor plus one exceeds FD_SETSIZE.

Returns an index vector to connections indicating connections with pending input, readable with precv.

If called at the client, the command connections are included into the UNIX select call and checked for error flags, and select_sockets returns an error if a flag for a remote error is received.

See also: pconnect, pserver, reval, psend, precv, sclose, parallel_generate_srp_data.