jyoung/external/zmq/share/man/man3/zframe.3

'\" t
.\"     Title: zframe
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
.\"      Date: 12/31/2016
.\"    Manual: CZMQ Manual
.\"    Source: CZMQ 4.0.2
.\"  Language: English
.\"
.TH "ZFRAME" "3" "12/31/2016" "CZMQ 4\&.0\&.2" "CZMQ Manual"
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.SH "NAME"
zframe \- working with single message frames
.SH "SYNOPSIS"
.sp
.nf
//  This is a stable class, and may not change except for emergencies\&. It
//  is provided in stable builds\&.
//  This class has draft methods, which may change over time\&. They are not
//  in stable releases, by default\&. Use \-\-enable\-drafts to enable\&.
#define ZFRAME_MORE 1                       //
#define ZFRAME_REUSE 2                      //
#define ZFRAME_DONTWAIT 4                   //

//  Create a new frame\&. If size is not null, allocates the frame data
//  to the specified size\&. If additionally, data is not null, copies
//  size octets from the specified data into the frame body\&.
CZMQ_EXPORT zframe_t *
    zframe_new (const void *data, size_t size);

//  Create an empty (zero\-sized) frame
CZMQ_EXPORT zframe_t *
    zframe_new_empty (void);

//  Create a frame with a specified string content\&.
CZMQ_EXPORT zframe_t *
    zframe_from (const char *string);

//  Receive frame from socket, returns zframe_t object or NULL if the recv
//  was interrupted\&. Does a blocking recv, if you want to not block then use
//  zpoller or zloop\&.
CZMQ_EXPORT zframe_t *
    zframe_recv (void *source);

//  Destroy a frame
CZMQ_EXPORT void
    zframe_destroy (zframe_t **self_p);

//  Send a frame to a socket, destroy frame after sending\&.
//  Return \-1 on error, 0 on success\&.
CZMQ_EXPORT int
    zframe_send (zframe_t **self_p, void *dest, int flags);

//  Return number of bytes in frame data
CZMQ_EXPORT size_t
    zframe_size (zframe_t *self);

//  Return address of frame data
CZMQ_EXPORT byte *
    zframe_data (zframe_t *self);

//  Return meta data property for frame
//  Caller must free string when finished with it\&.
CZMQ_EXPORT const char *
    zframe_meta (zframe_t *self, const char *property);

//  Create a new frame that duplicates an existing frame\&. If frame is null,
//  or memory was exhausted, returns null\&.
//  Caller owns return value and must destroy it when done\&.
CZMQ_EXPORT zframe_t *
    zframe_dup (zframe_t *self);

//  Return frame data encoded as printable hex string, useful for 0MQ UUIDs\&.
//  Caller must free string when finished with it\&.
//  Caller owns return value and must destroy it when done\&.
CZMQ_EXPORT char *
    zframe_strhex (zframe_t *self);

//  Return frame data copied into freshly allocated string
//  Caller must free string when finished with it\&.
//  Caller owns return value and must destroy it when done\&.
CZMQ_EXPORT char *
    zframe_strdup (zframe_t *self);

//  Return TRUE if frame body is equal to string, excluding terminator
CZMQ_EXPORT bool
    zframe_streq (zframe_t *self, const char *string);

//  Return frame MORE indicator (1 or 0), set when reading frame from socket
//  or by the zframe_set_more() method
CZMQ_EXPORT int
    zframe_more (zframe_t *self);

//  Set frame MORE indicator (1 or 0)\&. Note this is NOT used when sending
//  frame to socket, you have to specify flag explicitly\&.
CZMQ_EXPORT void
    zframe_set_more (zframe_t *self, int more);

//  Return TRUE if two frames have identical size and data
//  If either frame is NULL, equality is always false\&.
CZMQ_EXPORT bool
    zframe_eq (zframe_t *self, zframe_t *other);

//  Set new contents for frame
CZMQ_EXPORT void
    zframe_reset (zframe_t *self, const void *data, size_t size);

//  Send message to zsys log sink (may be stdout, or system facility as
//  configured by zsys_set_logstream)\&. Prefix shows before frame, if not null\&.
CZMQ_EXPORT void
    zframe_print (zframe_t *self, const char *prefix);

//  Probe the supplied object, and report if it looks like a zframe_t\&.
CZMQ_EXPORT bool
    zframe_is (void *self);

//  Self test of this class\&.
CZMQ_EXPORT void
    zframe_test (bool verbose);

#ifdef CZMQ_BUILD_DRAFT_API
//  *** Draft method, for development use, may change without warning ***
//  Return frame routing ID, if the frame came from a ZMQ_SERVER socket\&.
//  Else returns zero\&.
CZMQ_EXPORT uint32_t
    zframe_routing_id (zframe_t *self);

//  *** Draft method, for development use, may change without warning ***
//  Set routing ID on frame\&. This is used if/when the frame is sent to a
//  ZMQ_SERVER socket\&.
CZMQ_EXPORT void
    zframe_set_routing_id (zframe_t *self, uint32_t routing_id);

//  *** Draft method, for development use, may change without warning ***
//  Return frame group of radio\-dish pattern\&.
CZMQ_EXPORT const char *
    zframe_group (zframe_t *self);

//  *** Draft method, for development use, may change without warning ***
//  Set group on frame\&. This is used if/when the frame is sent to a
//  ZMQ_RADIO socket\&.
//  Return \-1 on error, 0 on success\&.
CZMQ_EXPORT int
    zframe_set_group (zframe_t *self, const char *group);

#endif // CZMQ_BUILD_DRAFT_API
Please add \*(Aq@interface\*(Aq section in \*(Aq\&./\&.\&./src/zframe\&.c\*(Aq\&.
.fi
.SH "DESCRIPTION"
.sp
The zframe class provides methods to send and receive single message frames across 0MQ sockets\&. A \fIframe\fR corresponds to one zmq_msg_t\&. When you read a frame from a socket, the zframe_more() method indicates if the frame is part of an unfinished multipart message\&. The zframe_send method normally destroys the frame, but with the ZFRAME_REUSE flag, you can send the same frame many times\&. Frames are binary, and this class has no special support for text data\&.
.sp
Please add \fI@discuss\fR section in \fI\&./\&.\&./src/zframe\&.c\fR\&.
.SH "EXAMPLE"
.PP
\fBFrom zframe_test method\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
//  Create two PAIR sockets and connect over inproc
zsock_t *output = zsock_new_pair ("@tcp://127\&.0\&.0\&.1:9001");
assert (output);
zsock_t *input = zsock_new_pair (">tcp://127\&.0\&.0\&.1:9001");
assert (input);

//  Send five different frames, test ZFRAME_MORE
int frame_nbr;
for (frame_nbr = 0; frame_nbr < 5; frame_nbr++) {
    frame = zframe_new ("Hello", 5);
    assert (frame);
    rc = zframe_send (&frame, output, ZFRAME_MORE);
    assert (rc == 0);
}
//  Send same frame five times, test ZFRAME_REUSE
frame = zframe_new ("Hello", 5);
assert (frame);
for (frame_nbr = 0; frame_nbr < 5; frame_nbr++) {
    rc = zframe_send (&frame, output, ZFRAME_MORE + ZFRAME_REUSE);
    assert (rc == 0);
}
assert (frame);
zframe_t *copy = zframe_dup (frame);
assert (zframe_eq (frame, copy));
zframe_destroy (&frame);
assert (!zframe_eq (frame, copy));
assert (zframe_size (copy) == 5);
zframe_destroy (&copy);
assert (!zframe_eq (frame, copy));

//  Test zframe_new_empty
frame = zframe_new_empty ();
assert (frame);
assert (zframe_size (frame) == 0);
zframe_destroy (&frame);

//  Send END frame
frame = zframe_new ("NOT", 3);
assert (frame);
zframe_reset (frame, "END", 3);
char *string = zframe_strhex (frame);
assert (streq (string, "454E44"));
free (string);
string = zframe_strdup (frame);
assert (streq (string, "END"));
free (string);
rc = zframe_send (&frame, output, 0);
assert (rc == 0);

//  Read and count until we receive END
frame_nbr = 0;
for (frame_nbr = 0;; frame_nbr++) {
    zframe_t *frame = zframe_recv (input);
    if (zframe_streq (frame, "END")) {
        zframe_destroy (&frame);
        break;
    }
    assert (zframe_more (frame));
    zframe_set_more (frame, 0);
    assert (zframe_more (frame) == 0);
    zframe_destroy (&frame);
}
assert (frame_nbr == 10);

#if (ZMQ_VERSION >= ZMQ_MAKE_VERSION (4, 1, 0))
// Test zframe_meta
frame = zframe_new ("Hello", 5);
assert (frame);
rc = zframe_send (&frame, output, 0);
assert (rc == 0);
frame = zframe_recv (input);
const char *meta = zframe_meta (frame, "Socket\-Type");
assert (meta != NULL);
assert (streq (meta, "PAIR"));
assert (zframe_meta (frame, "nonexistent") == NULL);
zframe_destroy (&frame);
#endif

zsock_destroy (&input);
zsock_destroy (&output);

#if defined (ZMQ_SERVER)
//  Create server and client sockets and connect over inproc
zsock_t *server = zsock_new_server ("inproc://zframe\-test\-routing");
assert (server);
zsock_t *client = zsock_new_client ("inproc://zframe\-test\-routing");
assert (client);

//  Send request from client to server
zframe_t *request = zframe_new ("Hello", 5);
assert (request);
rc = zframe_send (&request, client, 0);
assert (rc == 0);
assert (!request);

//  Read request and send reply
request = zframe_recv (server);
assert (request);
assert (zframe_streq (request, "Hello"));
assert (zframe_routing_id (request));

zframe_t *reply = zframe_new ("World", 5);
assert (reply);
zframe_set_routing_id (reply, zframe_routing_id (request));
rc = zframe_send (&reply, server, 0);
assert (rc == 0);
zframe_destroy (&request);

//  Read reply
reply = zframe_recv (client);
assert (zframe_streq (reply, "World"));
assert (zframe_routing_id (reply) == 0);
zframe_destroy (&reply);

//  Client and server disallow multipart
frame = zframe_new ("Hello", 5);
rc = zframe_send (&frame, client, ZFRAME_MORE);
assert (rc == \-1);
rc = zframe_send (&frame, server, ZFRAME_MORE);
assert (rc == \-1);
zframe_destroy (&frame);

zsock_destroy (&client);
zsock_destroy (&server);
#endif

#ifdef ZMQ_RADIO
//  Create radio and dish sockets and connect over inproc
zsock_t *radio = zsock_new_radio ("inproc://zframe\-test\-radio");
assert (radio);
zsock_t *dish = zsock_new_dish ("inproc://zframe\-test\-radio");
assert (dish);

//  Join the group
rc = zsock_join (dish, "World");
assert (rc == 0);

//  Publish message from radio
zframe_t *message = zframe_new ("Hello", 5);
assert (message);
rc = zframe_set_group (message, "World");
assert (rc == 0);
rc = zframe_send (&message, radio, 0);
assert (rc == 0);
assert (!message);

//  Receive the message from dish
message = zframe_recv (dish);
assert (message);
assert (zframe_streq (message, "Hello"));
assert (strcmp("World", zframe_group (message)) == 0);
zframe_destroy (&message);

zsock_destroy (&dish);
zsock_destroy (&radio);
#endif
.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) the 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