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1 | '\" |
2 | '\" Copyright (c) 1990-1994 The Regents of the University of California. | |
3 | '\" Copyright (c) 1994-1997 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: CrtFileHdlr.3,v 1.2 1998/09/14 18:39:47 stanton 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, | |
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18 | '\" needed; use .AS below instead) | |
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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. | |
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25 | '\" .BS | |
26 | '\" Start box enclosure. From here until next .BE, everything will be | |
27 | '\" enclosed in one large box. | |
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32 | '\" .CS | |
33 | '\" Begin code excerpt. | |
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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. | |
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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 | |
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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 | |
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120 | .. | |
121 | '\" # BE - end boxed text (draw box now) | |
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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' | |
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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 | |
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147 | .ie n 'mc \s12\(br\s0 | |
148 | .el .nr ^v 1u | |
149 | .. | |
150 | '\" # VE - end of vertical sidebar | |
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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 | |
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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 | |
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186 | .if \\n(^b \{\ | |
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193 | .. | |
194 | '\" # DS - begin display | |
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199 | .. | |
200 | '\" # DE - end display | |
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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 | |
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236 | .ta .25i .5i .75i 1i | |
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238 | '\" # CE - end code excerpt | |
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240 | .fi | |
241 | .RE | |
242 | .. | |
243 | .de UL | |
244 | \\$1\l'|0\(ul'\\$2 | |
245 | .. | |
246 | .TH Tcl_CreateFileHandler 3 8.0 Tcl "Tcl Library Procedures" | |
247 | .BS | |
248 | .SH NAME | |
249 | Tcl_CreateFileHandler, Tcl_DeleteFileHandler \- associate procedure callbacks with files or devices (Unix only) | |
250 | .SH SYNOPSIS | |
251 | .nf | |
252 | \fB#include <tcl.h>\fR | |
253 | .VS | |
254 | .sp | |
255 | \fBTcl_CreateFileHandler\fR(\fIfd, mask, proc, clientData\fR) | |
256 | .sp | |
257 | \fBTcl_DeleteFileHandler\fR(\fIfd\fR) | |
258 | .VE | |
259 | .SH ARGUMENTS | |
260 | .AS Tcl_FileProc clientData | |
261 | .VS | |
262 | .AP int fd in | |
263 | Unix file descriptor for an open file or device. | |
264 | .VE | |
265 | .AP int mask in | |
266 | Conditions under which \fIproc\fR should be called: | |
267 | OR-ed combination of \fBTCL_READABLE\fR, \fBTCL_WRITABLE\fR, | |
268 | and \fBTCL_EXCEPTION\fR. May be set to 0 to temporarily disable | |
269 | a handler. | |
270 | .AP Tcl_FileProc *proc in | |
271 | Procedure to invoke whenever the file or device indicated | |
272 | by \fIfile\fR meets the conditions specified by \fImask\fR. | |
273 | .AP ClientData clientData in | |
274 | Arbitrary one-word value to pass to \fIproc\fR. | |
275 | .BE | |
276 | ||
277 | .SH DESCRIPTION | |
278 | .PP | |
279 | .VS | |
280 | \fBTcl_CreateFileHandler\fR arranges for \fIproc\fR to be | |
281 | invoked in the future whenever I/O becomes possible on a file | |
282 | or an exceptional condition exists for the file. The file | |
283 | is indicated by \fIfd\fR, and the conditions of interest | |
284 | .VE | |
285 | are indicated by \fImask\fR. For example, if \fImask\fR | |
286 | is \fBTCL_READABLE\fR, \fIproc\fR will be called when | |
287 | the file is readable. | |
288 | The callback to \fIproc\fR is made by \fBTcl_DoOneEvent\fR, so | |
289 | \fBTcl_CreateFileHandler\fR is only useful in programs that dispatch | |
290 | events through \fBTcl_DoOneEvent\fR or through Tcl commands such | |
291 | as \fBvwait\fR. | |
292 | .PP | |
293 | \fIProc\fR should have arguments and result that match the | |
294 | type \fBTcl_FileProc\fR: | |
295 | .CS | |
296 | typedef void Tcl_FileProc( | |
297 | ClientData \fIclientData\fR, | |
298 | int \fImask\fR); | |
299 | .CE | |
300 | The \fIclientData\fR parameter to \fIproc\fR is a copy | |
301 | of the \fIclientData\fR | |
302 | argument given to \fBTcl_CreateFileHandler\fR when the callback | |
303 | was created. Typically, \fIclientData\fR points to a data | |
304 | structure containing application-specific information about | |
305 | the file. \fIMask\fR is an integer mask indicating which | |
306 | of the requested conditions actually exists for the file; it | |
307 | will contain a subset of the bits in the \fImask\fR argument | |
308 | to \fBTcl_CreateFileHandler\fR. | |
309 | .PP | |
310 | .PP | |
311 | There may exist only one handler for a given file at a given time. | |
312 | If \fBTcl_CreateFileHandler\fR is called when a handler already | |
313 | exists for \fIfd\fR, then the new callback replaces the information | |
314 | that was previously recorded. | |
315 | .PP | |
316 | \fBTcl_DeleteFileHandler\fR may be called to delete the | |
317 | file handler for \fIfd\fR; if no handler exists for the | |
318 | file given by \fIfd\fR then the procedure has no effect. | |
319 | .PP | |
320 | The purpose of file handlers is to enable an application to respond to | |
321 | events while waiting for files to become ready for I/O. For this to work | |
322 | correctly, the application may need to use non-blocking I/O operations on | |
323 | the files for which handlers are declared. Otherwise the application may | |
324 | block if it reads or writes too much data; while waiting for the I/O to | |
325 | complete the application won't be able to service other events. Use | |
326 | \fBTcl_SetChannelOption\fR with \fB\-blocking\fR to set the channel into | |
327 | blocking or nonblocking mode as required. | |
328 | .PP | |
329 | .VS | |
330 | Note that these interfaces are only supported by the Unix | |
331 | implementation of the Tcl notifier. | |
332 | .VE | |
333 | ||
334 | .SH KEYWORDS | |
335 | callback, file, handler |