zmq_ctx_set(3)
==============


NAME
----

zmq_ctx_set - set context options


SYNOPSIS
--------
*int zmq_ctx_set (void '*context', int 'option_name', int 'option_value');*


DESCRIPTION
-----------
The _zmq_ctx_set()_ function shall set the option specified by the
'option_name' argument to the value of the 'option_value' argument.

The _zmq_ctx_set()_ function accepts the following options:


ZMQ_IO_THREADS: Set number of I/O threads
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_IO_THREADS' argument specifies the size of the 0MQ thread pool to
handle I/O operations. If your application is using only the 'inproc'
transport for messaging you may set this to zero, otherwise set it to at
least one. This option only applies before creating any sockets on the
context.

[horizontal]
Default value:: 1

ZMQ_MAX_SOCKETS: Set maximum number of sockets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_MAX_SOCKETS' argument sets the maximum number of sockets allowed
on the context.

[horizontal]
Default value:: 1024

ZMQ_IPV6: Set IPv6 option
~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_IPV6' argument sets the IPv6 value for all sockets created in
the context from this point onwards. A value of `1` means IPv6 is
enabled, while `0` means the socket will use only IPv4. When IPv6 is
enabled, a socket will connect to, or accept connections from, both
IPv4 and IPv6 hosts.

[horizontal]
Default value:: 0


RETURN VALUE
------------
The _zmq_ctx_set()_ function returns zero if successful. Otherwise it
returns `-1` and sets 'errno' to one of the values defined below.


ERRORS
------
*EINVAL*::
The requested option _option_name_ is unknown.


EXAMPLE
-------
.Setting a limit on the number of sockets
----
void *context = zmq_ctx_new ();
zmq_ctx_set (context, ZMQ_MAX_SOCKETS, 256);
int max_sockets = zmq_ctx_get (context, ZMQ_MAX_SOCKETS);
assert (max_sockets == 256);
----


SEE ALSO
--------
linkzmq:zmq_ctx_get[3]
linkzmq:zmq[7]


AUTHORS
-------
This page was written by the 0MQ community. To make a change please
read the 0MQ Contribution Policy at <http://www.zeromq.org/docs:contributing>.
