xs_setctxopt(3)
===============


NAME
----

xs_setctxopt - set Crossroads context options


SYNOPSIS
--------
*int xs_setctxopt (void '*context', int 'option_name', const void '*option_value', size_t 'option_len');*

Caution: All options take effect only if set prior to creating the first socket.

DESCRIPTION
-----------
The _xs_setctxopt()_ function shall set the option specified by the
'option_name' argument to the value pointed to by the 'option_value' argument
for the Crossroads context pointed to by the 'context' argument.
The 'option_len' argument is the size of the option value in bytes.

The following options can be set with the _xs_setctxopt()_ function:


XS_CTX_MAX_SOCKETS: Set maximum number of sockets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'XS_CTX_MAX_SOCKETS' option shall set specify the maximum nuber of sockets
that can be open at the same time.

[horizontal]
Option value type:: int
Option value unit:: sockets
Default value:: 512

XS_CTX_REENTRANT: Specify whether sockets should be thread-safe
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If 'XS_CTX_REENTRANT' option is set to 1 it is safe to access single Crossroads
socket from multiple threads in parallel. If it is set to 0 it can be accessed
by at most one thread at any single point of time.

Note: By default Crossroads sockets are non-reentrant. If possible, try to use
the socket from the thread it was created in. If communication between threads
is needed use inproc transport. Not following this advice can introduce
scalability problems.

[horizontal]
Option value type:: int
Option value unit:: boolean
Default value:: 0

RETURN VALUE
------------
The _xs_setctxopt()_ function shall return zero if successful. Otherwise it
shall return `-1` and set 'errno' to one of the values defined below.


ERRORS
------
*EINVAL*::
The requested option _option_name_ is unknown, or the requested _option_len_ or
_option_value_ is invalid.
*EFAULT*::
The provided 'context' was invalid.

EXAMPLE
-------
.Setting maximal number of sockets to three.
----
int val = 3;
rc = xs_setctxopt (context, XS_CTX_MAX_SOCKETS, &val, sizeof (val));
assert (rc == 0);
----

SEE ALSO
--------
linkxs:xs_getsockopt[3]
linkxs:xs_setsockopt[3]
linkxs:xs_init[3]
linkxs:xs[7]


AUTHORS
-------
This manual page was written by Martin Sustrik <sustrik@250bpm.com>.