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'\" t
.\" Title: zmsg
.\" Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
.\" Date: 08/30/2011
.\" Manual: czmq Manual
.\" Source: czmq 1.1.0
.\" Language: English
.\"
.TH "ZMSG" "7" "08/30/2011" "czmq 1\&.1\&.0" "czmq Manual"
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.nh
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.\" * MAIN CONTENT STARTS HERE *
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.SH "NAME"
zmsg \- working with multipart messages
.SH "SYNOPSIS"
.sp
.nf
// Create a new empty message object
zmsg_t *
zmsg_new (void);
// Destroy a message object and all frames it contains
void
zmsg_destroy (zmsg_t **self_p);
// Read 1 or more frames off the socket, into a new message object
zmsg_t *
zmsg_recv (void *socket);
// Send a message to the socket, and then destroy it
void
zmsg_send (zmsg_t **self_p, void *socket);
// Return number of frames in message
size_t
zmsg_size (zmsg_t *self);
// Return combined size of all frames in message
size_t
zmsg_content_size (zmsg_t *self);
// Push frame to front of message, before first frame
void
zmsg_push (zmsg_t *self, zframe_t *frame);
// Pop frame off front of message, caller now owns frame
zframe_t *
zmsg_pop (zmsg_t *self);
// Add frame to end of message, after last frame
void
zmsg_add (zmsg_t *self, zframe_t *frame);
// Push block of memory as new frame to front of message
void
zmsg_pushmem (zmsg_t *self, const void *src, size_t size);
// Push block of memory as new frame to end of message
void
zmsg_addmem (zmsg_t *self, const void *src, size_t size);
// Push string as new frame to front of message
void
zmsg_pushstr (zmsg_t *self, const char *format, \&.\&.\&.);
// Push string as new frame to end of message
void
zmsg_addstr (zmsg_t *self, const char *format, \&.\&.\&.);
// Pop frame off front of message, return as fresh string
char *
zmsg_popstr (zmsg_t *self);
// Push frame to front of message, before first frame
// Pushes an empty frame in front of frame
void
zmsg_wrap (zmsg_t *self, zframe_t *frame);
// Pop frame off front of message, caller now owns frame
// If next frame is empty, pops and destroys that empty frame\&.
zframe_t *
zmsg_unwrap (zmsg_t *self);
// Remove frame from message, at any position, caller owns it
void
zmsg_remove (zmsg_t *self, zframe_t *frame);
// Return first frame in message, or null
zframe_t *
zmsg_first (zmsg_t *self);
// Return next frame in message, or null
zframe_t *
zmsg_next (zmsg_t *self);
// Return last frame in message, or null
zframe_t *
zmsg_last (zmsg_t *self);
// Save message to an open file, return 0 if OK, else \-1\&.
int
zmsg_save (zmsg_t *self, FILE *file);
// Load/append an open file into message, create new message if
// null message provided\&.
zmsg_t *
zmsg_load (zmsg_t *self, FILE *file);
// Encode message to a new buffer, return buffer size
size_t
zmsg_encode (zmsg_t *self, byte **buffer);
// Decode a buffer into a new message, returns NULL if buffer is not
// properly formatted\&.
zmsg_t *
zmsg_decode (byte *buffer, size_t buffer_size);
// Create copy of message, as new message object
zmsg_t *
zmsg_dup (zmsg_t *self);
// Print message to stderr, for debugging
void
zmsg_dump (zmsg_t *self);
// Self test of this class
int
zmsg_test (Bool verbose);
.fi
.SH "DESCRIPTION"
.sp
The zmsg class provides methods to send and receive multipart messages across 0MQ sockets\&. This class provides a list\-like container interface, with methods to work with the overall container\&. zmsg_t messages are composed of zero or more zframe_t frames\&.
.SH "EXAMPLE"
.PP
\fBFrom zmsg_test method\fR.
.sp
.if n \{\
.RS 4
.\}
.nf
zctx_t *ctx = zctx_new ();
void *output = zsocket_new (ctx, ZMQ_PAIR);
zsocket_bind (output, "inproc://zmsg\&.test");
void *input = zsocket_new (ctx, ZMQ_PAIR);
zsocket_connect (input, "inproc://zmsg\&.test");
// Test send and receive of single\-frame message
zmsg_t *msg = zmsg_new ();
zframe_t *frame = zframe_new ("Hello", 5);
zmsg_push (msg, frame);
assert (zmsg_size (msg) == 1);
assert (zmsg_content_size (msg) == 5);
zmsg_send (&msg, output);
assert (msg == NULL);
msg = zmsg_recv (input);
assert (msg);
assert (zmsg_size (msg) == 1);
assert (zmsg_content_size (msg) == 5);
zmsg_destroy (&msg);
// Test send and receive of multi\-frame message
msg = zmsg_new ();
zmsg_addmem (msg, "Frame0", 6);
zmsg_addmem (msg, "Frame1", 6);
zmsg_addmem (msg, "Frame2", 6);
zmsg_addmem (msg, "Frame3", 6);
zmsg_addmem (msg, "Frame4", 6);
zmsg_addmem (msg, "Frame5", 6);
zmsg_addmem (msg, "Frame6", 6);
zmsg_addmem (msg, "Frame7", 6);
zmsg_addmem (msg, "Frame8", 6);
zmsg_addmem (msg, "Frame9", 6);
zmsg_t *copy = zmsg_dup (msg);
zmsg_send (&copy, output);
zmsg_send (&msg, output);
copy = zmsg_recv (input);
assert (copy);
assert (zmsg_size (copy) == 10);
assert (zmsg_content_size (copy) == 60);
zmsg_destroy (&copy);
msg = zmsg_recv (input);
assert (msg);
assert (zmsg_size (msg) == 10);
assert (zmsg_content_size (msg) == 60);
if (verbose)
zmsg_dump (msg);
// Save to a file, read back
FILE *file = fopen ("zmsg\&.test", "w");
assert (file);
int rc = zmsg_save (msg, file);
assert (rc == 0);
fclose (file);
file = fopen ("zmsg\&.test", "r");
rc = zmsg_save (msg, file);
assert (rc == \-1);
fclose (file);
zmsg_destroy (&msg);
file = fopen ("zmsg\&.test", "r");
msg = zmsg_load (NULL, file);
fclose (file);
remove ("zmsg\&.test");
assert (zmsg_size (msg) == 10);
assert (zmsg_content_size (msg) == 60);
// Remove all frames except first and last
int frame_nbr;
for (frame_nbr = 0; frame_nbr < 8; frame_nbr++) {
zmsg_first (msg);
frame = zmsg_next (msg);
zmsg_remove (msg, frame);
zframe_destroy (&frame);
}
// Test message frame manipulation
assert (zmsg_size (msg) == 2);
assert (zmsg_content_size (msg) == 12);
frame = zframe_new ("Address", 7);
zmsg_wrap (msg, frame);
assert (zmsg_size (msg) == 4);
zmsg_addstr (msg, "Body");
assert (zmsg_size (msg) == 5);
frame = zmsg_unwrap (msg);
zframe_destroy (&frame);
assert (zmsg_size (msg) == 3);
char *body = zmsg_popstr (msg);
assert (streq (body, "Frame0"));
free (body);
zmsg_destroy (&msg);
// Test encoding/decoding
msg = zmsg_new ();
byte *blank = zmalloc (100000);
zmsg_addmem (msg, blank, 0);
zmsg_addmem (msg, blank, 1);
zmsg_addmem (msg, blank, 253);
zmsg_addmem (msg, blank, 254);
zmsg_addmem (msg, blank, 255);
zmsg_addmem (msg, blank, 256);
zmsg_addmem (msg, blank, 65535);
zmsg_addmem (msg, blank, 65536);
zmsg_addmem (msg, blank, 65537);
free (blank);
assert (zmsg_size (msg) == 9);
byte *buffer;
size_t buffer_size = zmsg_encode (msg, &buffer);
zmsg_destroy (&msg);
msg = zmsg_decode (buffer, buffer_size);
assert (msg);
free (buffer);
zmsg_destroy (&msg);
// Now try methods on an empty message
msg = zmsg_new ();
assert (zmsg_size (msg) == 0);
assert (zmsg_first (msg) == NULL);
assert (zmsg_next (msg) == NULL);
assert (zmsg_pop (msg) == NULL);
zmsg_destroy (&msg);
zctx_destroy (&ctx);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBczmq\fR(7)
.SH "AUTHORS"
.sp
The czmq manual was written by Pieter Hintjens<\m[blue]\fBph@imatix\&.com\fR\m[]\&\s-2\u[1]\d\s+2>\&.
.SH "RESOURCES"
.sp
Main web site: \m[blue]\fBhttp://czmq\&.zeromq\&.org/\fR\m[]
.sp
Report bugs to the 0MQ development mailing list: <\m[blue]\fBzeromq\-dev@lists\&.zeromq\&.org\fR\m[]\&\s-2\u[2]\d\s+2>
.SH "COPYRIGHT"
.sp
Copyright (c) 1991\-2010 iMatix Corporation and contributors\&. License LGPLv3+: GNU LGPL 3 or later <\m[blue]\fBhttp://gnu\&.org/licenses/lgpl\&.html\fR\m[]>\&. This is free software: you are free to change it and redistribute it\&. There is NO WARRANTY, to the extent permitted by law\&. For details see the files COPYING and COPYING\&.LESSER included with the czmq distribution\&.
.SH "NOTES"
.IP " 1." 4
ph@imatix.com
.RS 4
\%mailto:ph@imatix.com
.RE
.IP " 2." 4
zeromq-dev@lists.zeromq.org
.RS 4
\%mailto:zeromq-dev@lists.zeromq.org
.RE