= nng_pull(7)
:copyright: Copyright 2018 mailto:info@staysail.tech[Staysail Systems, Inc.] + \
	    Copyright 2018 mailto:info@capitar.com[Capitar IT Group BV] + \
	    {blank} + \
	    This document is supplied under the terms of the \
	    https://opensource.org/licenses/MIT[MIT License].

== NAME

nng_pull - pull protocol

== SYNOPSIS

[source,c]
----------
#include <nng/protocol/pipeline0/pull.h>

int nng_pull0_open(nng_socket *s);
----------

== DESCRIPTION

The _nng_pull_ protocol is one half of a pipeline pattern. The other half
is the <<nng_push#,nng_push(7)>> protocol.

In the pipeline pattern, pushers distribute messages to pullers. 
Each message sent
by a pusher will be sent to one of its peer pullers,
chosen in a round-robin fashion
from the set of connected peers available for receiving.
This property makes this pattern useful in load-balancing scenarios.

=== Socket Operations

The `nng_pull0_open()` call creates a puller socket.  This socket
may be used to receive messages, but is unable to send them.  Attempts
to send messages will result in `NNG_ENOTSUP`.

When receiving messages, the _nng_pull_ protocol accepts messages as
they arrive from peers.  If two peers both have a message ready, the
order in which messages are handled is undefined.

=== Protocol Versions

Only version 0 of this protocol is supported.  (At the time of writing,
no other versions of this protocol have been defined.)

=== Protocol Options

The _nng_pull_ protocol has no protocol-specific options.

=== Protocol Headers

The _nng_pull_ protocol has no protocol-specific headers.
    
== SEE ALSO

<<nng#,nng(7)>>,
<<nng_push#,nng_push(7)>>

== COPYRIGHT

{copyright}
