You can edit this page using wiki syntax for markup.

Article contents:== Outdated egg! This is an egg for CHICKEN 3, the unsupported old release. You're almost certainly looking for [[/eggref/4/spread|the CHICKEN 4 version of this egg]], if it exists. If it does not exist, there may be equivalent functionality provided by another egg; have a look at the [[https://wiki.call-cc.org/chicken-projects/egg-index-4.html|egg index]]. Otherwise, please consider porting this egg to the current version of CHICKEN. [[tags: egg]] == spread [[toc:]] === Description A library for using the [[http://www.spread.org|Spread]] multicast group communication system. === Author [[/users/felix winkelmann|felix winkelmann]] === Requirements [[easyffi]] === Download [[http://code.call-cc.org/legacy-eggs/3/spread.egg|spread.egg]] === Documentation You should be roughly familiar with the Spread system and it's API - this document does not attempt to explain Spread in every detail. For additional information see the [[http://www.spread.org|Spread website]]. Spread has to be properly installed for this extension to work. These procedures return an unspecified value, unless documented otherwise. Should an invocation of the Spread API fail, a composite condition of the kinds {{(exn spread)}} will be signalled, with the additional property {{code}}, containing the spread error code. <procedure>(sp:connect [SPREAD-NAME] #!key PRIVATE-NAME PRIORITY GROUP-MEMBERSHIP)</procedure> Connects to a Spread daemon. {{SPREAD-NAME}} should be of the form {{"<port-number>"}} or {{"<port-number>@<host-name>"}}. {{PRIVATE-NAME}} is a string naming the connection (defaults to a randomly generated name) and should be unique on the machine running the daemon. If {{GROUP-MEMBERSHIP}} is given and not {{#f}}, then this connection will receive group-membership messages. {{PRIORITY}} is currently not used. If {{SPREAD-NAME}} is not given it defaults to a string containing the default port for spread (usually 4803). Returns a connection object. <procedure>(sp:connection? X)</procedure> Returns {{#t}} if {{X}} is a connection object or {{#f}} otherwise. <procedure>(sp:connection-private-group CONNECTION)</procedure> Returns the private group name of this connection as assigned by the Spread daemon. <procedure>(sp:disconnect CONNECTION)</procedure> Terminates the connection. Note that a process may have multiple connections. <procedure>(sp:join CONNECTION GROUP)</procedure> Joins the group with the name {{GROUP}} (a string). If no group with this name exists, it is created. <procedure>(sp:leave CONNECTION GROUP)</procedure> Leaves the group with the name {{GROUP}} (a string). If the group does not exist, this operation is does nothing. <procedure>(sp:multicast CONNECTION SERVICE-TYPE GROUP MESSAGE #!key SELF-DISCARD MESSAGE-TYPE)</procedure> Sends a message to one or more groups. {{MESSAGE}} is a string containing the message to be sent, via {{CONNECTION}} and to the group or groups given in {{GROUP}} (either a string or a list of strings). The {{SERVICE-TYPE}} argument should be one of the symbols {{unreliable, reliable, fifo, causal, agreed}} or {{safe}} and specifies what kind of service is requested. {{MESSAGE-TYPE}} can be an arbitrary message code that Spread will send unchanged to all recipients. If {{SELF-DISCARD}} is given and true, then messages sent by this connection are not sent back to the sender (the same connection). <procedure>(sp:receive CONNECTION #!key MAX-GROUPS DROP-RECV MAX-MESSAGE-LENGTH DESTINATION)</procedure> Waits for a message from the Spread daemon on the given connection. {{MAX-GROUPS}} gives the maximal number of groups to be returned in the message object and defaults to 16. {{MAX-MESSAGE-LENGTH}} gives the maximal size of the buffer receiving the message (defaults to 1024 bytes). DESTINATION is the buffer to store the message in. If no destination is given a new buffer will be allocated. If the received message is larger than the destination buffer and {{MAX-MESSAGE-LENGTH}} is not given, then the buffer will be automatically resized and the receive-operation will be repeated. If {{MAX-MESSAGE-LENGTH}} is given and the destination is too small, an error will be signalled. Returns a message object. '''FIXME: find explanation for {{DROP-RECV}}.''' <procedure>(sp:message X)</procedure> Returns {{#t}} if {{X}} is a message object or {{#f}} otherwise. <procedure>(sp:message-data MESSAGE)</procedure> Returns the contents of the message: either a string (if a regular message) or a list of groups (if a regular membership message). <procedure>(sp:message-endian-mismatch? MESSAGE)</procedure> Returns {{#t}} if the endianness of the sending machine differs from that of this receiving machine. <procedure>(sp:message-sender MESSAGE)</procedure> Returns the private group name of the sending connection or the group name, if a membership message. <procedure>(sp:message-groups MESSAGE)</procedure> A list of the names of all groups receiving this message. <procedure>(sp:message-service-type MESSAGE)</procedure> A list of symbols designating the type of this message. Possible members are: unreliable reliable fifo causal agreed safe regular regular-membership transition caused-by-join caused-by-leave caused-by-disconnect caused-by-network membership <procedure>(sp:message-type MESSAGE)</procedure> An arbitrary integer code sent with the message. <procedure>(sp:regular-message? MESSAGE)</procedure> Returns {{#t}} if the message is a regular (data) message, or {{#f}} otherwise. <procedure>(sp:regular-membership-message? MESSAGE)</procedure> Returns {{#t}} if the message is a regular membership (join/leave) message, or {{#f}} otherwise. <procedure>(sp:transitional-membership-message? MESSAGE)</procedure> Returns {{#t}} if the message is a ''transitional'' membership message, or {{#f}} otherwise. (This is a message that designates a membership-change to be occurring in the future. Unfortunately this is not fully documented in the Spread manuals). <procedure>(sp:self-leave-message? MESSAGE)</procedure> Returns {{#t}} if the message is a membership (leave) message of this connection, or {{#f}} otherwise. <procedure>(sp:poll CONNECTION)</procedure> Returns {{#t}} if there is a message ready for receival (i.e. the next {{sp:receive}} will not block), or {{#f}} otherwise. <procedure>(sp:version)</procedure> Returns three values, the major- and minor version number of the used Spread library and its patch-level. === Examples A simple sender/receiver pair: <enscript highlight="scheme"> ; sender.scm (require-extension spread posix srfi-1) (define c (sp:connect)) (sp:join c "foobar") (define (print-message x) (print "SENDER: " (sp:message-service-type x) " - " (sp:message-data x)) ) (let loop () (sleep 1) (sp:multicast c 'reliable "foobar" (->string (reverse (iota (random (add1 100)))))) (do () ((not (sp:poll c))) (print-message (sp:receive c)) ) (loop) ) </enscript> <enscript highlight="scheme"> ; receiver.scm (require-extension spread) (define c (sp:connect)) (sp:join c "foobar") (define (print-message x) (print "RECEIVER: " (sp:message-service-type x) " - " (sp:message-data x)) ) (let loop () (let ([msg (sp:receive c)]) (print-message msg) (when (sp:regular-message? msg) (let ([lst (with-input-from-string (sp:message-data msg) read)]) (assert (= (add1 (car lst)) (length lst))) ) ) (loop) ) ) </enscript> === Changelog * 1.3 Removed use of {{___callback}}. * 1.2 The {{self-discard:}} keyword-argument to {{sp:multicast}} defaults to {{#t}}. * 1.1 Adapted to new FFI macro names * 1.0 Initial release === License This product uses software developed by Spread Concepts LLC for use in the Spread toolkit. For more information about Spread see [[http://www.spread.org]] Copyright (c) 2004, Felix L. Winkelmann All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Description of your changes:

I would like to authenticate

Spam control

What do you get when you multiply 1 by 8?