'\" t .\" Title: zctx .\" Author: [see the "AUTHORS" section] .\" Generator: DocBook XSL Stylesheets v1.78.1 .\" Date: 09/14/2016 .\" Manual: CZMQ Manual .\" Source: CZMQ 3.0.2 .\" Language: English .\" .TH "ZCTX" "3" "09/14/2016" "CZMQ 3\&.0\&.2" "CZMQ Manual" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" zctx \- working with 0MQ contexts (deprecated) .SH "SYNOPSIS" .sp .nf // Create new context, returns context object, replaces zmq_init CZMQ_EXPORT zctx_t * zctx_new (void); // Destroy context and all sockets in it, replaces zmq_term CZMQ_EXPORT void zctx_destroy (zctx_t **self_p); // Create new shadow context, returns context object CZMQ_EXPORT zctx_t * zctx_shadow (zctx_t *self); // Raise default I/O threads from 1, for crazy heavy applications // The rule of thumb is one I/O thread per gigabyte of traffic in // or out\&. Call this method before creating any sockets on the context, // or calling zctx_shadow, or the setting will have no effect\&. CZMQ_EXPORT void zctx_set_iothreads (zctx_t *self, int iothreads); // Set msecs to flush sockets when closing them, see the ZMQ_LINGER // man page section for more details\&. By default, set to zero, so // any in\-transit messages are discarded when you destroy a socket or // a context\&. CZMQ_EXPORT void zctx_set_linger (zctx_t *self, int linger); // Set initial high\-water mark for inter\-thread pipe sockets\&. Note that // this setting is separate from the default for normal sockets\&. You // should change the default for pipe sockets *with care*\&. Too low values // will cause blocked threads, and an infinite setting can cause memory // exhaustion\&. The default, no matter the underlying ZeroMQ version, is // 1,000\&. CZMQ_EXPORT void zctx_set_pipehwm (zctx_t *self, int pipehwm); // Set initial send HWM for all new normal sockets created in context\&. // You can set this per\-socket after the socket is created\&. // The default, no matter the underlying ZeroMQ version, is 1,000\&. CZMQ_EXPORT void zctx_set_sndhwm (zctx_t *self, int sndhwm); // Set initial receive HWM for all new normal sockets created in context\&. // You can set this per\-socket after the socket is created\&. // The default, no matter the underlying ZeroMQ version, is 1,000\&. CZMQ_EXPORT void zctx_set_rcvhwm (zctx_t *self, int rcvhwm); // Return low\-level 0MQ context object, will be NULL before first socket // is created\&. Use with care\&. CZMQ_EXPORT void * zctx_underlying (zctx_t *self); // Self test of this class CZMQ_EXPORT void zctx_test (bool verbose); .fi .SH "DESCRIPTION" .sp The zctx class wraps 0MQ contexts\&. It manages open sockets in the context and automatically closes these before terminating the context\&. It provides a simple way to set the linger timeout on sockets, and configure contexts for number of I/O threads\&. Sets\-up signal (interrupt) handling for the process\&. .sp The zctx class has these main features: .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Tracks all open sockets and automatically closes them before calling zmq_term()\&. This avoids an infinite wait on open sockets\&. .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Automatically configures sockets with a ZMQ_LINGER timeout you can define, and which defaults to zero\&. The default behavior of zctx is therefore like 0MQ/2\&.0, immediate termination with loss of any pending messages\&. You can set any linger timeout you like by calling the zctx_set_linger() method\&. .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Moves the iothreads configuration to a separate method, so that default usage is 1 I/O thread\&. Lets you configure this value\&. .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Sets up signal (SIGINT and SIGTERM) handling so that blocking calls such as zmq_recv() and zmq_poll() will return when the user presses Ctrl\-C\&. .RE .if n \{\ .sp .\} .RS 4 .it 1 an-trap .nr an-no-space-flag 1 .nr an-break-flag 1 .br .ps +1 \fBNote\fR .ps -1 .br .sp this class is deprecated in favor of zsock, which does not expose contexts in the API at all\&. All zsock instances use the same global context\&. .sp .5v .RE .SH "EXAMPLE" .PP \fBFrom zctx_test method\fR. .sp .if n \{\ .RS 4 .\} .nf // Create and destroy a context without using it zctx_t *ctx = zctx_new (); assert (ctx); zctx_destroy (&ctx); assert (ctx == NULL); // Create a context with many busy sockets, destroy it ctx = zctx_new (); assert (ctx); zctx_set_iothreads (ctx, 1); zctx_set_linger (ctx, 5); // 5 msecs void *s1 = zctx__socket_new (ctx, ZMQ_PAIR); assert (s1); void *s2 = zctx__socket_new (ctx, ZMQ_XREQ); assert (s2); void *s3 = zctx__socket_new (ctx, ZMQ_REQ); assert (s3); void *s4 = zctx__socket_new (ctx, ZMQ_REP); assert (s4); void *s5 = zctx__socket_new (ctx, ZMQ_PUB); assert (s5); void *s6 = zctx__socket_new (ctx, ZMQ_SUB); assert (s6); int rc = zsocket_connect (s1, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); rc = zsocket_connect (s2, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); rc = zsocket_connect (s3, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); rc = zsocket_connect (s4, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); rc = zsocket_connect (s5, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); rc = zsocket_connect (s6, "tcp://127\&.0\&.0\&.1:5555"); assert (rc == 0); assert (zctx_underlying (ctx)); zctx_destroy (&ctx); .fi .if n \{\ .RE .\} .sp .SH "AUTHORS" .sp The czmq manual was written by the authors in the AUTHORS file\&. .SH "RESOURCES" .sp Main web site: \m[blue]\fB\%\fR\m[] .sp Report bugs to the email <\m[blue]\fBzeromq\-dev@lists\&.zeromq\&.org\fR\m[]\&\s-2\u[1]\d\s+2> .SH "COPYRIGHT" .sp Copyright (c) 1991\-2012 iMatix Corporation \-\- http://www\&.imatix\&.com Copyright other contributors as noted in the AUTHORS file\&. This file is part of CZMQ, the high\-level C binding for 0MQ: http://czmq\&.zeromq\&.org This Source Code Form is subject to the terms of the Mozilla Public License, v\&. 2\&.0\&. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla\&.org/MPL/2\&.0/\&. LICENSE included with the czmq distribution\&. .SH "NOTES" .IP " 1." 4 zeromq-dev@lists.zeromq.org .RS 4 \%mailto:zeromq-dev@lists.zeromq.org .RE