Mercurial > hg > xemacs-beta
annotate lisp/multicast.el @ 5609:3152c2c21461
Correct and clarify docstring, #'load-time-value
lisp/ChangeLog addition:
2011-12-09 Aidan Kehoe <kehoea@parhasard.net>
* cl-macs.el (load-time-value):
Clarify the docstring here, thanks for pointing out its inaccuracy
Julian Bradfield.
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Fri, 09 Dec 2011 08:38:07 +0000 |
| parents | ac37a5f7e5be |
| children |
| rev | line source |
|---|---|
| 261 | 1 ;;; multicast.el --- lisp frontend for multicast connections in XEmacs |
| 2 | |
| 404 | 3 ;; Copyright (C) 1997-2000 Didier Verna. |
| 853 | 4 ;; Copyright (C) 2002 Ben Wing. |
| 261 | 5 |
| 404 | 6 ;; Author: Didier Verna <didier@xemacs.org> |
| 7 ;; Maintainer: Didier Verna <didier@xemacs.org> | |
| 8 ;; Created: Thu Dec 4 16:37:39 1997 | |
| 261 | 9 ;; Last Revision: Mon Jan 19 19:10:50 1998 |
| 10 ;; Current Version: 0.4 | |
| 11 ;; Keywords: dumped comm processes | |
| 12 | |
| 404 | 13 ;; This file is part of XEmacs. |
| 261 | 14 |
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15 ;; XEmacs is free software: you can redistribute it and/or modify it |
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16 ;; under the terms of the GNU General Public License as published by the |
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17 ;; Free Software Foundation, either version 3 of the License, or (at your |
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18 ;; option) any later version. |
| 261 | 19 |
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20 ;; XEmacs is distributed in the hope that it will be useful, but WITHOUT |
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21 ;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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22 ;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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23 ;; for more details. |
| 261 | 24 |
| 25 ;; You should have received a copy of the GNU General Public License | |
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26 ;; along with XEmacs. If not, see <http://www.gnu.org/licenses/>. |
| 261 | 27 |
| 28 ;;; Commentary: | |
| 29 | |
| 30 ;; This file just contains a lisp frontend to the internal function | |
| 31 ;; open-multicast-group-internal written in C and belonging to process.c | |
| 32 ;; Well, nothing much to say about it ... read the doc string. | |
| 33 | |
| 34 | |
| 35 ;;; Change Log: | |
| 36 | |
| 37 ;; Rev. of Mon Jan 19 19:04:44 1998 : packaging cleanup | |
| 38 ;; Rev. of Thu Dec 11 13:54:26 1997 : updated the docstring | |
| 39 ;; Rev. of Mon Dec 8 15:28:47 1997 : Improved the doc string | |
| 40 ;; Rev. of Thu Dec 4 16:38:09 1997 : Initial Version. | |
| 41 | |
| 42 | |
| 43 ;;; Code: | |
| 44 | |
| 45 (defun open-multicast-group (name buffer address) | |
| 46 "Open a multicast connection on the specified address. | |
| 444 | 47 Returns a process object to represent the connection. |
| 261 | 48 Input and output work as for subprocesses; `delete-process' closes it. |
| 49 NAME is a name for the process. It is modified if necessary to make it unique. | |
| 50 BUFFER is the buffer (or buffer-name) to associate with the process. | |
| 51 Process output goes at the end of that buffer, unless you specify an output | |
| 52 stream or filter function to handle the output. | |
| 53 BUFFER may be also nil, meaning that this process is not associated with any | |
| 853 | 54 buffer. |
| 261 | 55 ADDRESS specifies a standard multicast address \"dest/port/ttl\": |
| 56 dest is an internet address between 224.0.0.0 and 239.255.255.255 | |
| 57 port is a communication port like in traditional unicast | |
| 58 ttl is the time-to-live (15 for site, 63 for region and 127 for world). | |
| 59 | |
| 60 WARNING: it is *strongly* recommended to avoid using groups beginning with | |
| 404 | 61 224 or 239. Such groups are considered 'admin' groups, and may |
| 853 | 62 behave in a surprising way ... |
| 63 | |
| 64 The read/write coding systems used for process I/O on the process are | |
| 65 determined as follows: | |
| 66 | |
| 67 1. `coding-system-for-read', `coding-system-for-write', if non-nil. | |
| 68 (Intended as a temporary overriding mechanism for use by Lisp | |
| 69 code.) | |
| 70 2. The matching value for the port from `network-coding-system-alist', | |
| 71 if any, and if non-nil. The value may be either a single coding | |
| 72 system, used for both read and write; or a cons of read/write; or a | |
| 73 function, called to get one of the other two values. | |
| 74 3. The value of `default-network-coding-system', which should be a cons | |
| 75 of read/write coding systems, if the values are non-nil. | |
| 76 4. The coding system `undecided' for read, and `raw-text' for write. | |
| 77 | |
| 78 Note that the processes of determining the read and write coding systems | |
| 79 proceed essentially independently one from the other, as in `start-process'. | |
| 80 | |
| 81 You can change the coding systems later on using | |
| 82 `set-process-coding-system', `set-process-input-coding-system', or | |
| 83 `set-process-output-coding-system'." | |
| 261 | 84 (let (dest port ttl) |
| 85 ;; We check only the general form of the multicast address. | |
| 86 ;; The rest will be handled by the internal function. | |
| 87 (string-match "^\\([0-9\\.]+\\)/\\([0-9]+\\)/\\([0-9]+\\)$" address) | |
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88 (and (not (and (eql (match-beginning 0) 0) |
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f00192e1cd49
Examining the result of #'length: `eql', not `=', it's better style & cheaper
Aidan Kehoe <kehoea@parhasard.net>
parents:
5235
diff
changeset
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89 (eql (match-end 0) (length address)))) |
| 261 | 90 (error "malformed multicast address: %s" address)) |
| 91 (and (not (setq dest (match-string 1 address))) | |
| 92 (error "invalid destination specification.")) | |
| 93 (and (= 0 (setq port (string-to-int (match-string 2 address)))) | |
| 94 (error "invalid port specification.")) | |
| 95 (and (= 0 (setq ttl (string-to-int (match-string 3 address)))) | |
| 96 (error "invalid ttl specification.")) | |
| 853 | 97 (let (cs-r cs-w) |
| 98 (let (ret) | |
| 99 (catch 'found | |
| 100 (let ((alist network-coding-system-alist) | |
| 101 (case-fold-search nil) | |
| 102 pattern) | |
| 103 (while alist | |
| 104 (setq pattern (car (car alist))) | |
| 105 (and | |
| 106 (cond ((numberp pattern) | |
| 107 (and (numberp port) | |
| 108 (eq pattern port))) | |
| 109 ((stringp pattern) | |
| 110 (or (and (stringp port) | |
| 111 (string-match pattern port)) | |
| 112 (and (numberp port) | |
| 113 (string-match pattern | |
| 114 (number-to-string port)))))) | |
| 115 (throw 'found (setq ret (cdr (car alist))))) | |
| 116 (setq alist (cdr alist)) | |
| 117 ))) | |
| 118 (if (functionp ret) | |
| 119 (setq ret (funcall ret 'open-multicast-group port))) | |
| 120 (cond ((consp ret) | |
| 121 (setq cs-r (car ret) | |
| 122 cs-w (cdr ret))) | |
| 123 ((and ret (find-coding-system ret)) | |
| 124 (setq cs-r ret | |
| 125 cs-w ret)))) | |
| 126 (let ((coding-system-for-read | |
| 127 (or coding-system-for-read cs-r | |
| 128 (car default-network-coding-system) | |
| 129 'undecided)) | |
| 130 (coding-system-for-write | |
| 131 (or coding-system-for-write cs-w | |
| 132 (cdr default-network-coding-system) | |
| 133 'raw-text))) | |
| 134 (declare-fboundp (open-multicast-group-internal name buffer dest port | |
| 135 ttl)))))) | |
| 404 | 136 |
| 261 | 137 ;;; multicast.el ends here |