raw/mann/unknown.n

   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: unknown.n,v 1.1 2003/12/20 03:31:54 bbbush 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?
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  38 '\" .VS ?version? ?br?
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  56 '\"     options follow on successive lines, in four columns separated
  57 '\"     by tabs.
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  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: unknown.n,v 1.1 2003/12/20 03:31:54 bbbush 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
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 118 .if n \l'\\n(.lu\(ul'
 119 .if n .fi
 120 ..
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 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
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 140 ..
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 153 .el \{\
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 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 ..
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 170 'ti 0
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 172 .mk ^t
 173 .if \\n(^b \{\
 174 .\"     Draw three-sided box if this is the box's first page,
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 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 ..
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 195 .de DS
 196 .RS
 197 .nf
 198 .sp
 199 ..
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 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 ..
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 239 .de CE
 240 .fi
 241 .RE
 242 ..
 243 .de UL
 244 \\$1\l'|0\(ul'\\$2
 245 ..
 246 .TH unknown n "" Tcl "Tcl Built-In Commands"
 247 .BS
 248 '\" Note:  do not modify the .SH NAME line immediately below!
 249 .SH NAME
 250 unknown \- Handle attempts to use non-existent commands
 251 .SH SYNOPSIS
 252 \fBunknown \fIcmdName \fR?\fIarg arg ...\fR?
 253 .BE
 254
 255 .SH DESCRIPTION
 256 .PP
 257 This command is invoked by the Tcl interpreter whenever a script
 258 tries to invoke a command that doesn't exist.  The implementation
 259 of \fBunknown\fR isn't part of the Tcl core;  instead, it is a
 260 library procedure defined by default when Tcl starts up.  You
 261 can override the default \fBunknown\fR to change its functionality.
 262 .PP
 263 If the Tcl interpreter encounters a command name for which there
 264 is not a defined command, then Tcl checks for the existence of
 265 a command named \fBunknown\fR.
 266 If there is no such command, then the interpreter returns an
 267 error.
 268 If the \fBunknown\fR command exists, then it is invoked with
 269 arguments consisting of the fully-substituted name and arguments
 270 for the original non-existent command.
 271 The \fBunknown\fR command typically does things like searching
 272 through library directories for a command procedure with the name
 273 \fIcmdName\fR, or expanding abbreviated command names to full-length,
 274 or automatically executing unknown commands as sub-processes.
 275 In some cases (such as expanding abbreviations) \fBunknown\fR will
 276 change the original command slightly and then (re-)execute it.
 277 The result of the \fBunknown\fR command is used as the result for
 278 the original non-existent command.
 279 .PP
 280 The default implementation of \fBunknown\fR behaves as follows.
 281 It first calls the \fBauto_load\fR library procedure to load the command.
 282 If this succeeds, then it executes the original command with its
 283 original arguments.
 284 If the auto-load fails then \fBunknown\fR calls \fBauto_execok\fR
 285 to see if there is an executable file by the name \fIcmd\fR.
 286 If so, it invokes the Tcl \fBexec\fR command
 287 with \fIcmd\fR and all the \fIargs\fR as arguments.
 288 If \fIcmd\fR can't be auto-executed, \fBunknown\fR checks to
 289 see if the command was invoked at top-level and outside of any
 290 script.  If so, then \fBunknown\fR takes two additional steps.
 291 First, it sees if \fIcmd\fR has one of the following three forms:
 292 \fB!!\fR, \fB!\fIevent\fR, or \fB^\fIold\fB^\fInew\fR?\fB^\fR?.
 293 If so, then \fBunknown\fR carries out history substitution
 294 in the same way that \fBcsh\fR would for these constructs.
 295 Finally, \fBunknown\fR checks to see if \fIcmd\fR is
 296 a unique abbreviation for an existing Tcl command.
 297 If so, it expands the command name and executes the command with
 298 the original arguments.
 299 If none of the above efforts has been able to execute
 300 the command, \fBunknown\fR generates an error return.
 301 If the global variable \fBauto_noload\fR is defined, then the auto-load
 302 step is skipped.
 303 If the global variable \fBauto_noexec\fR is defined then the
 304 auto-exec step is skipped.
 305 Under normal circumstances the return value from \fBunknown\fR
 306 is the return value from the command that was eventually
 307 executed.
 308
 309 .SH "SEE ALSO"
 310 info(n), proc(n)
 311
 312 .SH KEYWORDS
 313 error, non-existent command