Commit | Line | Data |
---|---|---|
920dae64 AT |
1 | '\" |
2 | '\" Copyright (c) 1993 The Regents of the University of California. | |
3 | '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. | |
4 | '\" | |
5 | '\" See the file "license.terms" for information on usage and redistribution | |
6 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. | |
7 | '\" | |
8 | '\" RCS: @(#) $Id: read.n,v 1.7.8.1 2004/10/27 14:23:57 dkf Exp $ | |
9 | '\" | |
10 | '\" The definitions below are for supplemental macros used in Tcl/Tk | |
11 | '\" manual entries. | |
12 | '\" | |
13 | '\" .AP type name in/out ?indent? | |
14 | '\" Start paragraph describing an argument to a library procedure. | |
15 | '\" type is type of argument (int, etc.), in/out is either "in", "out", | |
16 | '\" or "in/out" to describe whether procedure reads or modifies arg, | |
17 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be | |
18 | '\" needed; use .AS below instead) | |
19 | '\" | |
20 | '\" .AS ?type? ?name? | |
21 | '\" Give maximum sizes of arguments for setting tab stops. Type and | |
22 | '\" name are examples of largest possible arguments that will be passed | |
23 | '\" to .AP later. If args are omitted, default tab stops are used. | |
24 | '\" | |
25 | '\" .BS | |
26 | '\" Start box enclosure. From here until next .BE, everything will be | |
27 | '\" enclosed in one large box. | |
28 | '\" | |
29 | '\" .BE | |
30 | '\" End of box enclosure. | |
31 | '\" | |
32 | '\" .CS | |
33 | '\" Begin code excerpt. | |
34 | '\" | |
35 | '\" .CE | |
36 | '\" End code excerpt. | |
37 | '\" | |
38 | '\" .VS ?version? ?br? | |
39 | '\" Begin vertical sidebar, for use in marking newly-changed parts | |
40 | '\" of man pages. The first argument is ignored and used for recording | |
41 | '\" the version when the .VS was added, so that the sidebars can be | |
42 | '\" found and removed when they reach a certain age. If another argument | |
43 | '\" is present, then a line break is forced before starting the sidebar. | |
44 | '\" | |
45 | '\" .VE | |
46 | '\" End of vertical sidebar. | |
47 | '\" | |
48 | '\" .DS | |
49 | '\" Begin an indented unfilled display. | |
50 | '\" | |
51 | '\" .DE | |
52 | '\" End of indented unfilled display. | |
53 | '\" | |
54 | '\" .SO | |
55 | '\" Start of list of standard options for a Tk widget. The | |
56 | '\" options follow on successive lines, in four columns separated | |
57 | '\" by tabs. | |
58 | '\" | |
59 | '\" .SE | |
60 | '\" End of list of standard options for a Tk widget. | |
61 | '\" | |
62 | '\" .OP cmdName dbName dbClass | |
63 | '\" Start of description of a specific option. cmdName gives the | |
64 | '\" option's name as specified in the class command, dbName gives | |
65 | '\" the option's name in the option database, and dbClass gives | |
66 | '\" the option's class in the option database. | |
67 | '\" | |
68 | '\" .UL arg1 arg2 | |
69 | '\" Print arg1 underlined, then print arg2 normally. | |
70 | '\" | |
71 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ | |
72 | '\" | |
73 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. | |
74 | .if t .wh -1.3i ^B | |
75 | .nr ^l \n(.l | |
76 | .ad b | |
77 | '\" # Start an argument description | |
78 | .de AP | |
79 | .ie !"\\$4"" .TP \\$4 | |
80 | .el \{\ | |
81 | . ie !"\\$2"" .TP \\n()Cu | |
82 | . el .TP 15 | |
83 | .\} | |
84 | .ta \\n()Au \\n()Bu | |
85 | .ie !"\\$3"" \{\ | |
86 | \&\\$1 \\fI\\$2\\fP (\\$3) | |
87 | .\".b | |
88 | .\} | |
89 | .el \{\ | |
90 | .br | |
91 | .ie !"\\$2"" \{\ | |
92 | \&\\$1 \\fI\\$2\\fP | |
93 | .\} | |
94 | .el \{\ | |
95 | \&\\fI\\$1\\fP | |
96 | .\} | |
97 | .\} | |
98 | .. | |
99 | '\" # define tabbing values for .AP | |
100 | .de AS | |
101 | .nr )A 10n | |
102 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n | |
103 | .nr )B \\n()Au+15n | |
104 | .\" | |
105 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n | |
106 | .nr )C \\n()Bu+\\w'(in/out)'u+2n | |
107 | .. | |
108 | .AS Tcl_Interp Tcl_CreateInterp in/out | |
109 | '\" # BS - start boxed text | |
110 | '\" # ^y = starting y location | |
111 | '\" # ^b = 1 | |
112 | .de BS | |
113 | .br | |
114 | .mk ^y | |
115 | .nr ^b 1u | |
116 | .if n .nf | |
117 | .if n .ti 0 | |
118 | .if n \l'\\n(.lu\(ul' | |
119 | .if n .fi | |
120 | .. | |
121 | '\" # BE - end boxed text (draw box now) | |
122 | .de BE | |
123 | .nf | |
124 | .ti 0 | |
125 | .mk ^t | |
126 | .ie n \l'\\n(^lu\(ul' | |
127 | .el \{\ | |
128 | .\" Draw four-sided box normally, but don't draw top of | |
129 | .\" box if the box started on an earlier page. | |
130 | .ie !\\n(^b-1 \{\ | |
131 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
132 | .\} | |
133 | .el \}\ | |
134 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
135 | .\} | |
136 | .\} | |
137 | .fi | |
138 | .br | |
139 | .nr ^b 0 | |
140 | .. | |
141 | '\" # VS - start vertical sidebar | |
142 | '\" # ^Y = starting y location | |
143 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) | |
144 | .de VS | |
145 | .if !"\\$2"" .br | |
146 | .mk ^Y | |
147 | .ie n 'mc \s12\(br\s0 | |
148 | .el .nr ^v 1u | |
149 | .. | |
150 | '\" # VE - end of vertical sidebar | |
151 | .de VE | |
152 | .ie n 'mc | |
153 | .el \{\ | |
154 | .ev 2 | |
155 | .nf | |
156 | .ti 0 | |
157 | .mk ^t | |
158 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' | |
159 | .sp -1 | |
160 | .fi | |
161 | .ev | |
162 | .\} | |
163 | .nr ^v 0 | |
164 | .. | |
165 | '\" # Special macro to handle page bottom: finish off current | |
166 | '\" # box/sidebar if in box/sidebar mode, then invoked standard | |
167 | '\" # page bottom macro. | |
168 | .de ^B | |
169 | .ev 2 | |
170 | 'ti 0 | |
171 | 'nf | |
172 | .mk ^t | |
173 | .if \\n(^b \{\ | |
174 | .\" Draw three-sided box if this is the box's first page, | |
175 | .\" draw two sides but no top otherwise. | |
176 | .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c | |
177 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c | |
178 | .\} | |
179 | .if \\n(^v \{\ | |
180 | .nr ^x \\n(^tu+1v-\\n(^Yu | |
181 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c | |
182 | .\} | |
183 | .bp | |
184 | 'fi | |
185 | .ev | |
186 | .if \\n(^b \{\ | |
187 | .mk ^y | |
188 | .nr ^b 2 | |
189 | .\} | |
190 | .if \\n(^v \{\ | |
191 | .mk ^Y | |
192 | .\} | |
193 | .. | |
194 | '\" # DS - begin display | |
195 | .de DS | |
196 | .RS | |
197 | .nf | |
198 | .sp | |
199 | .. | |
200 | '\" # DE - end display | |
201 | .de DE | |
202 | .fi | |
203 | .RE | |
204 | .sp | |
205 | .. | |
206 | '\" # SO - start of list of standard options | |
207 | .de SO | |
208 | .SH "STANDARD OPTIONS" | |
209 | .LP | |
210 | .nf | |
211 | .ta 5.5c 11c | |
212 | .ft B | |
213 | .. | |
214 | '\" # SE - end of list of standard options | |
215 | .de SE | |
216 | .fi | |
217 | .ft R | |
218 | .LP | |
219 | See the \\fBoptions\\fR manual entry for details on the standard options. | |
220 | .. | |
221 | '\" # OP - start of full description for a single option | |
222 | .de OP | |
223 | .LP | |
224 | .nf | |
225 | .ta 4c | |
226 | Command-Line Name: \\fB\\$1\\fR | |
227 | Database Name: \\fB\\$2\\fR | |
228 | Database Class: \\fB\\$3\\fR | |
229 | .fi | |
230 | .IP | |
231 | .. | |
232 | '\" # CS - begin code excerpt | |
233 | .de CS | |
234 | .RS | |
235 | .nf | |
236 | .ta .25i .5i .75i 1i | |
237 | .. | |
238 | '\" # CE - end code excerpt | |
239 | .de CE | |
240 | .fi | |
241 | .RE | |
242 | .. | |
243 | .de UL | |
244 | \\$1\l'|0\(ul'\\$2 | |
245 | .. | |
246 | .TH read n 8.1 Tcl "Tcl Built-In Commands" | |
247 | .BS | |
248 | '\" Note: do not modify the .SH NAME line immediately below! | |
249 | .SH NAME | |
250 | read \- Read from a channel | |
251 | .SH SYNOPSIS | |
252 | \fBread \fR?\fB\-nonewline\fR? \fIchannelId\fR | |
253 | .sp | |
254 | \fBread \fIchannelId numChars\fR | |
255 | .BE | |
256 | ||
257 | .SH DESCRIPTION | |
258 | .PP | |
259 | In the first form, the \fBread\fR command reads all of the data from | |
260 | \fIchannelId\fR up to the end of the file. If the \fB\-nonewline\fR | |
261 | switch is specified then the last character of the file is discarded | |
262 | if it is a newline. In the second form, the extra argument specifies | |
263 | how many characters to read. Exactly that many characters will be | |
264 | read and returned, unless there are fewer than \fInumChars\fR left in | |
265 | the file; in this case all the remaining characters are returned. If | |
266 | the channel is configured to use a multi-byte encoding, then the | |
267 | number of characters read may not be the same as the number of bytes | |
268 | read. | |
269 | .PP | |
270 | .VS | |
271 | \fIChannelId\fR must be an identifier for an open channel such as the | |
272 | Tcl standard input channel (\fBstdin\fR), the return value from an | |
273 | invocation of \fBopen\fR or \fBsocket\fR, or the result of a channel | |
274 | creation command provided by a Tcl extension. The channel must have | |
275 | been opened for input. | |
276 | .VE | |
277 | .PP | |
278 | If \fIchannelId\fR is in nonblocking mode, the command may not read as | |
279 | many characters as requested: once all available input has been read, | |
280 | the command will return the data that is available rather than | |
281 | blocking for more input. If the channel is configured to use a | |
282 | multi-byte encoding, then there may actually be some bytes remaining | |
283 | in the internal buffers that do not form a complete character. These | |
284 | bytes will not be returned until a complete character is available or | |
285 | end-of-file is reached. The \fB\-nonewline\fR switch is ignored if | |
286 | the command returns before reaching the end of the file. | |
287 | .PP | |
288 | \fBRead\fR translates end-of-line sequences in the input into | |
289 | newline characters according to the \fB\-translation\fR option | |
290 | for the channel. | |
291 | See the \fBfconfigure\fR manual entry for a discussion on ways in | |
292 | which \fBfconfigure\fR will alter input. | |
293 | ||
294 | .SH "USE WITH SERIAL PORTS" | |
295 | '\" Note: this advice actually applies to many versions of Tcl | |
296 | ||
297 | For most applications a channel connected to a serial port should be | |
298 | configured to be nonblocking: \fBfconfigure \fIchannelId \fB\-blocking | |
299 | \fI0\fR. Then \fBread\fR behaves much like described above. Care | |
300 | must be taken when using \fBread\fR on blocking serial ports: | |
301 | .TP | |
302 | \fBread \fIchannelId numChars\fR | |
303 | In this form \fBread\fR blocks until \fInumChars\fR have been received | |
304 | from the serial port. | |
305 | .TP | |
306 | \fBread \fIchannelId\fR | |
307 | In this form \fBread\fR blocks until the reception of the end-of-file | |
308 | character, see \fBfconfigure -eofchar\fR. If there no end-of-file | |
309 | character has been configured for the channel, then \fBread\fR will | |
310 | block forever. | |
311 | .SH "EXAMPLE" | |
312 | This example code reads a file all at once, and splits it into a list, | |
313 | with each line in the file corresponding to an element in the list: | |
314 | .CS | |
315 | set fl [open /proc/meminfo] | |
316 | set data [\fBread\fR $fl] | |
317 | close $fl | |
318 | set lines [split $data \\n] | |
319 | .CE | |
320 | ||
321 | .SH "SEE ALSO" | |
322 | file(n), eof(n), fblocked(n), fconfigure(n), Tcl_StandardChannels(3) | |
323 | ||
324 | .SH KEYWORDS | |
325 | blocking, channel, end of line, end of file, nonblocking, read, translation, encoding |