Commit | Line | Data |
---|---|---|
920dae64 AT |
1 | '\" |
2 | '\" Copyright (c) 2002 Donal K. Fellows | |
3 | '\" | |
4 | '\" See the file "license.terms" for information on usage and redistribution | |
5 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. | |
6 | '\" | |
7 | '\" CVS: @(#) $Id: TraceCmd.3,v 1.5 2002/07/01 18:24:39 jenglish Exp $ | |
8 | '\" | |
9 | '\" The definitions below are for supplemental macros used in Tcl/Tk | |
10 | '\" manual entries. | |
11 | '\" | |
12 | '\" .AP type name in/out ?indent? | |
13 | '\" Start paragraph describing an argument to a library procedure. | |
14 | '\" type is type of argument (int, etc.), in/out is either "in", "out", | |
15 | '\" or "in/out" to describe whether procedure reads or modifies arg, | |
16 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be | |
17 | '\" needed; use .AS below instead) | |
18 | '\" | |
19 | '\" .AS ?type? ?name? | |
20 | '\" Give maximum sizes of arguments for setting tab stops. Type and | |
21 | '\" name are examples of largest possible arguments that will be passed | |
22 | '\" to .AP later. If args are omitted, default tab stops are used. | |
23 | '\" | |
24 | '\" .BS | |
25 | '\" Start box enclosure. From here until next .BE, everything will be | |
26 | '\" enclosed in one large box. | |
27 | '\" | |
28 | '\" .BE | |
29 | '\" End of box enclosure. | |
30 | '\" | |
31 | '\" .CS | |
32 | '\" Begin code excerpt. | |
33 | '\" | |
34 | '\" .CE | |
35 | '\" End code excerpt. | |
36 | '\" | |
37 | '\" .VS ?version? ?br? | |
38 | '\" Begin vertical sidebar, for use in marking newly-changed parts | |
39 | '\" of man pages. The first argument is ignored and used for recording | |
40 | '\" the version when the .VS was added, so that the sidebars can be | |
41 | '\" found and removed when they reach a certain age. If another argument | |
42 | '\" is present, then a line break is forced before starting the sidebar. | |
43 | '\" | |
44 | '\" .VE | |
45 | '\" End of vertical sidebar. | |
46 | '\" | |
47 | '\" .DS | |
48 | '\" Begin an indented unfilled display. | |
49 | '\" | |
50 | '\" .DE | |
51 | '\" End of indented unfilled display. | |
52 | '\" | |
53 | '\" .SO | |
54 | '\" Start of list of standard options for a Tk widget. The | |
55 | '\" options follow on successive lines, in four columns separated | |
56 | '\" by tabs. | |
57 | '\" | |
58 | '\" .SE | |
59 | '\" End of list of standard options for a Tk widget. | |
60 | '\" | |
61 | '\" .OP cmdName dbName dbClass | |
62 | '\" Start of description of a specific option. cmdName gives the | |
63 | '\" option's name as specified in the class command, dbName gives | |
64 | '\" the option's name in the option database, and dbClass gives | |
65 | '\" the option's class in the option database. | |
66 | '\" | |
67 | '\" .UL arg1 arg2 | |
68 | '\" Print arg1 underlined, then print arg2 normally. | |
69 | '\" | |
70 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ | |
71 | '\" | |
72 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. | |
73 | .if t .wh -1.3i ^B | |
74 | .nr ^l \n(.l | |
75 | .ad b | |
76 | '\" # Start an argument description | |
77 | .de AP | |
78 | .ie !"\\$4"" .TP \\$4 | |
79 | .el \{\ | |
80 | . ie !"\\$2"" .TP \\n()Cu | |
81 | . el .TP 15 | |
82 | .\} | |
83 | .ta \\n()Au \\n()Bu | |
84 | .ie !"\\$3"" \{\ | |
85 | \&\\$1 \\fI\\$2\\fP (\\$3) | |
86 | .\".b | |
87 | .\} | |
88 | .el \{\ | |
89 | .br | |
90 | .ie !"\\$2"" \{\ | |
91 | \&\\$1 \\fI\\$2\\fP | |
92 | .\} | |
93 | .el \{\ | |
94 | \&\\fI\\$1\\fP | |
95 | .\} | |
96 | .\} | |
97 | .. | |
98 | '\" # define tabbing values for .AP | |
99 | .de AS | |
100 | .nr )A 10n | |
101 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n | |
102 | .nr )B \\n()Au+15n | |
103 | .\" | |
104 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n | |
105 | .nr )C \\n()Bu+\\w'(in/out)'u+2n | |
106 | .. | |
107 | .AS Tcl_Interp Tcl_CreateInterp in/out | |
108 | '\" # BS - start boxed text | |
109 | '\" # ^y = starting y location | |
110 | '\" # ^b = 1 | |
111 | .de BS | |
112 | .br | |
113 | .mk ^y | |
114 | .nr ^b 1u | |
115 | .if n .nf | |
116 | .if n .ti 0 | |
117 | .if n \l'\\n(.lu\(ul' | |
118 | .if n .fi | |
119 | .. | |
120 | '\" # BE - end boxed text (draw box now) | |
121 | .de BE | |
122 | .nf | |
123 | .ti 0 | |
124 | .mk ^t | |
125 | .ie n \l'\\n(^lu\(ul' | |
126 | .el \{\ | |
127 | .\" Draw four-sided box normally, but don't draw top of | |
128 | .\" box if the box started on an earlier page. | |
129 | .ie !\\n(^b-1 \{\ | |
130 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
131 | .\} | |
132 | .el \}\ | |
133 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
134 | .\} | |
135 | .\} | |
136 | .fi | |
137 | .br | |
138 | .nr ^b 0 | |
139 | .. | |
140 | '\" # VS - start vertical sidebar | |
141 | '\" # ^Y = starting y location | |
142 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) | |
143 | .de VS | |
144 | .if !"\\$2"" .br | |
145 | .mk ^Y | |
146 | .ie n 'mc \s12\(br\s0 | |
147 | .el .nr ^v 1u | |
148 | .. | |
149 | '\" # VE - end of vertical sidebar | |
150 | .de VE | |
151 | .ie n 'mc | |
152 | .el \{\ | |
153 | .ev 2 | |
154 | .nf | |
155 | .ti 0 | |
156 | .mk ^t | |
157 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' | |
158 | .sp -1 | |
159 | .fi | |
160 | .ev | |
161 | .\} | |
162 | .nr ^v 0 | |
163 | .. | |
164 | '\" # Special macro to handle page bottom: finish off current | |
165 | '\" # box/sidebar if in box/sidebar mode, then invoked standard | |
166 | '\" # page bottom macro. | |
167 | .de ^B | |
168 | .ev 2 | |
169 | 'ti 0 | |
170 | 'nf | |
171 | .mk ^t | |
172 | .if \\n(^b \{\ | |
173 | .\" Draw three-sided box if this is the box's first page, | |
174 | .\" draw two sides but no top otherwise. | |
175 | .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 | |
176 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c | |
177 | .\} | |
178 | .if \\n(^v \{\ | |
179 | .nr ^x \\n(^tu+1v-\\n(^Yu | |
180 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c | |
181 | .\} | |
182 | .bp | |
183 | 'fi | |
184 | .ev | |
185 | .if \\n(^b \{\ | |
186 | .mk ^y | |
187 | .nr ^b 2 | |
188 | .\} | |
189 | .if \\n(^v \{\ | |
190 | .mk ^Y | |
191 | .\} | |
192 | .. | |
193 | '\" # DS - begin display | |
194 | .de DS | |
195 | .RS | |
196 | .nf | |
197 | .sp | |
198 | .. | |
199 | '\" # DE - end display | |
200 | .de DE | |
201 | .fi | |
202 | .RE | |
203 | .sp | |
204 | .. | |
205 | '\" # SO - start of list of standard options | |
206 | .de SO | |
207 | .SH "STANDARD OPTIONS" | |
208 | .LP | |
209 | .nf | |
210 | .ta 5.5c 11c | |
211 | .ft B | |
212 | .. | |
213 | '\" # SE - end of list of standard options | |
214 | .de SE | |
215 | .fi | |
216 | .ft R | |
217 | .LP | |
218 | See the \\fBoptions\\fR manual entry for details on the standard options. | |
219 | .. | |
220 | '\" # OP - start of full description for a single option | |
221 | .de OP | |
222 | .LP | |
223 | .nf | |
224 | .ta 4c | |
225 | Command-Line Name: \\fB\\$1\\fR | |
226 | Database Name: \\fB\\$2\\fR | |
227 | Database Class: \\fB\\$3\\fR | |
228 | .fi | |
229 | .IP | |
230 | .. | |
231 | '\" # CS - begin code excerpt | |
232 | .de CS | |
233 | .RS | |
234 | .nf | |
235 | .ta .25i .5i .75i 1i | |
236 | .. | |
237 | '\" # CE - end code excerpt | |
238 | .de CE | |
239 | .fi | |
240 | .RE | |
241 | .. | |
242 | .de UL | |
243 | \\$1\l'|0\(ul'\\$2 | |
244 | .. | |
245 | .TH Tcl_TraceCommand 3 7.4 Tcl "Tcl Library Procedures" | |
246 | .BS | |
247 | .SH NAME | |
248 | Tcl_CommandTraceInfo, Tcl_TraceCommand, Tcl_UntraceCommand \- monitor renames and deletes of a command | |
249 | .SH SYNOPSIS | |
250 | .nf | |
251 | \fB#include <tcl.h>\fR | |
252 | .sp | |
253 | ClientData | |
254 | \fBTcl_CommandTraceInfo(\fIinterp, cmdName, flags, proc, prevClientData\fB)\fR | |
255 | .sp | |
256 | int | |
257 | \fBTcl_TraceCommand(\fIinterp, cmdName, flags, proc, clientData\fB)\fR | |
258 | .sp | |
259 | void | |
260 | \fBTcl_UntraceCommand(\fIinterp, cmdName, flags, proc, clientData\fB)\fR | |
261 | .SH ARGUMENTS | |
262 | .AS Tcl_CommandTraceProc prevClientData | |
263 | .AP Tcl_Interp *interp in | |
264 | Interpreter containing the command. | |
265 | .AP "CONST char" *cmdName in | |
266 | Name of command. | |
267 | .AP int flags in | |
268 | OR-ed collection of the value TCL_TRACE_RENAME and TCL_TRACE_DELETE. | |
269 | .AP Tcl_CommandTraceProc *proc in | |
270 | Procedure to call when specified operations occur to \fIcmdName\fR. | |
271 | .AP ClientData clientData in | |
272 | Arbitrary argument to pass to \fIproc\fR. | |
273 | .AP ClientData prevClientData in | |
274 | If non-NULL, gives last value returned by \fBTcl_CommandTraceInfo\fR, | |
275 | so this call will return information about next trace. If NULL, this | |
276 | call will return information about first trace. | |
277 | .BE | |
278 | ||
279 | .SH DESCRIPTION | |
280 | .PP | |
281 | \fBTcl_TraceCommand\fR allows a C procedure to monitor operations | |
282 | performed on a Tcl command, so that the C procedure is invoked | |
283 | whenever the command is renamed or deleted. If the trace is created | |
284 | successfully then \fBTcl_TraceCommand\fR returns TCL_OK. If an error | |
285 | occurred (e.g. \fIcmdName\fR specifies a non-existent command) then | |
286 | TCL_ERROR is returned and an error message is left in the | |
287 | interpreter's result. | |
288 | .PP | |
289 | The \fIflags\fR argument to \fBTcl_TraceCommand\fR indicates when the | |
290 | trace procedure is to be invoked. It consists of an OR-ed combination | |
291 | of any of the following values: | |
292 | .TP | |
293 | \fBTCL_TRACE_RENAME\fR | |
294 | Invoke \fIproc\fR whenever the command is renamed. | |
295 | .TP | |
296 | \fBTCL_TRACE_DELETE\fR | |
297 | Invoke \fIproc\fR when the command is deleted. | |
298 | .PP | |
299 | Whenever one of the specified operations occurs to the command, | |
300 | \fIproc\fR will be invoked. It should have arguments and result that | |
301 | match the type \fBTcl_CommandTraceProc\fR: | |
302 | .CS | |
303 | typedef void Tcl_CommandTraceProc( | |
304 | ClientData \fIclientData\fR, | |
305 | Tcl_Interp *\fIinterp\fR, | |
306 | CONST char *\fIoldName\fR, | |
307 | CONST char *\fInewName\fR, | |
308 | int \fIflags\fR); | |
309 | .CE | |
310 | The \fIclientData\fR and \fIinterp\fR parameters will have the same | |
311 | values as those passed to \fBTcl_TraceCommand\fR when the trace was | |
312 | created. \fIClientData\fR typically points to an application-specific | |
313 | data structure that describes what to do when \fIproc\fR is invoked. | |
314 | \fIOldName\fR gives the name of the command being renamed, and | |
315 | \fInewName\fR gives the name that the command is being renamed to (or | |
316 | an empty string or NULL when the command is being deleted.) | |
317 | \fIFlags\fR is an OR-ed combination of bits potentially providing | |
318 | several pieces of information. One of the bits TCL_TRACE_RENAME and | |
319 | TCL_TRACE_DELETE will be set in \fIflags\fR to indicate which | |
320 | operation is being performed on the command. The bit | |
321 | TCL_TRACE_DESTROYED will be set in \fIflags\fR if the trace is about | |
322 | to be destroyed; this information may be useful to \fIproc\fR so that | |
323 | it can clean up its own internal data structures (see the section | |
324 | TCL_TRACE_DESTROYED below for more details). Lastly, the bit | |
325 | TCL_INTERP_DESTROYED will be set if the entire interpreter is being | |
326 | destroyed. When this bit is set, \fIproc\fR must be especially | |
327 | careful in the things it does (see the section TCL_INTERP_DESTROYED | |
328 | below). | |
329 | .PP | |
330 | \fBTcl_UntraceCommand\fR may be used to remove a trace. If the | |
331 | command specified by \fIinterp\fR, \fIcmdName\fR, and \fIflags\fR has | |
332 | a trace set with \fIflags\fR, \fIproc\fR, and \fIclientData\fR, then | |
333 | the corresponding trace is removed. If no such trace exists, then the | |
334 | call to \fBTcl_UntraceCommand\fR has no effect. The same bits are | |
335 | valid for \fIflags\fR as for calls to \fBTcl_TraceCommand\fR. | |
336 | .PP | |
337 | \fBTcl_CommandTraceInfo\fR may be used to retrieve information about | |
338 | traces set on a given command. | |
339 | The return value from \fBTcl_CommandTraceInfo\fR is the \fIclientData\fR | |
340 | associated with a particular trace. | |
341 | The trace must be on the command specified by the \fIinterp\fR, | |
342 | \fIcmdName\fR, and \fIflags\fR arguments (note that currently the | |
343 | flags are ignored; \fIflags\fR should be set to 0 for future | |
344 | compatibility) and its trace procedure must the same as the \fIproc\fR | |
345 | argument. | |
346 | If the \fIprevClientData\fR argument is NULL then the return | |
347 | value corresponds to the first (most recently created) matching | |
348 | trace, or NULL if there are no matching traces. | |
349 | If the \fIprevClientData\fR argument isn't NULL, then it should | |
350 | be the return value from a previous call to \fBTcl_CommandTraceInfo\fR. | |
351 | In this case, the new return value will correspond to the next | |
352 | matching trace after the one whose \fIclientData\fR matches | |
353 | \fIprevClientData\fR, or NULL if no trace matches \fIprevClientData\fR | |
354 | or if there are no more matching traces after it. | |
355 | This mechanism makes it possible to step through all of the | |
356 | traces for a given command that have the same \fIproc\fR. | |
357 | ||
358 | .SH "CALLING COMMANDS DURING TRACES" | |
359 | .PP | |
360 | During rename traces, the command being renamed is visible with both | |
361 | names simultaneously, and the command still exists during delete | |
362 | traces (if TCL_INTERP_DESTROYED is not set). However, there is no | |
363 | mechanism for signaling that an error occurred in a trace procedure, | |
364 | so great care should be taken that errors do not get silently lost. | |
365 | ||
366 | .SH "MULTIPLE TRACES" | |
367 | .PP | |
368 | It is possible for multiple traces to exist on the same command. | |
369 | When this happens, all of the trace procedures will be invoked on each | |
370 | access, in order from most-recently-created to least-recently-created. | |
371 | Attempts to delete the command during a delete trace will fail | |
372 | silently, since the command is already scheduled for deletion anyway. | |
373 | If the command being renamed is renamed by one of its rename traces, | |
374 | that renaming takes precedence over the one that triggered the trace | |
375 | and the collection of traces will not be reexecuted; if several traces | |
376 | rename the command, the last renaming takes precedence. | |
377 | ||
378 | .SH "TCL_TRACE_DESTROYED FLAG" | |
379 | .PP | |
380 | In a delete callback to \fIproc\fR, the TCL_TRACE_DESTROYED bit | |
381 | is set in \fIflags\fR. | |
382 | ||
383 | '\" Perhaps need some more comments here? - DKF | |
384 | ||
385 | .SH "TCL_INTERP_DESTROYED" | |
386 | .PP | |
387 | When an interpreter is destroyed, unset traces are called for | |
388 | all of its commands. | |
389 | The TCL_INTERP_DESTROYED bit will be set in the \fIflags\fR | |
390 | argument passed to the trace procedures. | |
391 | Trace procedures must be extremely careful in what they do if | |
392 | the TCL_INTERP_DESTROYED bit is set. | |
393 | It is not safe for the procedures to invoke any Tcl procedures | |
394 | on the interpreter, since its state is partially deleted. | |
395 | All that trace procedures should do under these circumstances is | |
396 | to clean up and free their own internal data structures. | |
397 | ||
398 | .SH BUGS | |
399 | .PP | |
400 | Tcl doesn't do any error checking to prevent trace procedures | |
401 | from misusing the interpreter during traces with TCL_INTERP_DESTROYED | |
402 | set. | |
403 | ||
404 | .SH KEYWORDS | |
405 | clientData, trace, command |