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.

       Default value   1

   ZMQ_THREAD_SCHED_POLICY: Set scheduling policy for I/O threads
       The ZMQ_THREAD_SCHED_POLICY argument sets the scheduling policy for internal context’s
       thread pool. This option is not available on windows. Supported values for this option can
       be found in sched.h file, or at
       http://man7.org/linux/man-pages/man2/sched_setscheduler.2.html. This option only applies
       before creating any sockets on the context.

       Default value   -1

   ZMQ_THREAD_PRIORITY: Set scheduling priority for I/O threads
       The ZMQ_THREAD_PRIORITY argument sets scheduling priority for internal context’s thread
       pool. This option is not available on windows. Supported values for this option depend on
       chosen scheduling policy. Details can be found in sched.h file, or at
       http://man7.org/linux/man-pages/man2/sched_setscheduler.2.html. This option only applies
       before creating any sockets on the context.

       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.
       You can query the maximal allowed value with zmq_ctx_get(3) using the ZMQ_SOCKET_LIMIT
       option.

       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.

       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

       zmq_ctx_get(3) zmq(7)

AUTHORS

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