| 1 | '\" |
| 2 | '\" Copyright (c) 1992-1995 Karl Lehenbauer and Mark Diekhans. |
| 3 | '\" Copyright (c) 1995-1997 Sun Microsystems, Inc. |
| 4 | '\" Copyright (c) 1998-1999 Scriptics Corporation |
| 5 | '\" Copyright (c) 2002 ActiveState Corporation |
| 6 | '\" |
| 7 | '\" This documentation is derived from the time and date facilities of |
| 8 | '\" TclX, by Mark Diekhans and Karl Lehenbauer. |
| 9 | '\" |
| 10 | '\" See the file "license.terms" for information on usage and redistribution |
| 11 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| 12 | '\" |
| 13 | '\" RCS: @(#) $Id: clock.n,v 1.11.2.6 2004/12/13 15:52:21 kennykb Exp $ |
| 14 | '\" |
| 15 | '\" The definitions below are for supplemental macros used in Tcl/Tk |
| 16 | '\" manual entries. |
| 17 | '\" |
| 18 | '\" .AP type name in/out ?indent? |
| 19 | '\" Start paragraph describing an argument to a library procedure. |
| 20 | '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| 21 | '\" or "in/out" to describe whether procedure reads or modifies arg, |
| 22 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| 23 | '\" needed; use .AS below instead) |
| 24 | '\" |
| 25 | '\" .AS ?type? ?name? |
| 26 | '\" Give maximum sizes of arguments for setting tab stops. Type and |
| 27 | '\" name are examples of largest possible arguments that will be passed |
| 28 | '\" to .AP later. If args are omitted, default tab stops are used. |
| 29 | '\" |
| 30 | '\" .BS |
| 31 | '\" Start box enclosure. From here until next .BE, everything will be |
| 32 | '\" enclosed in one large box. |
| 33 | '\" |
| 34 | '\" .BE |
| 35 | '\" End of box enclosure. |
| 36 | '\" |
| 37 | '\" .CS |
| 38 | '\" Begin code excerpt. |
| 39 | '\" |
| 40 | '\" .CE |
| 41 | '\" End code excerpt. |
| 42 | '\" |
| 43 | '\" .VS ?version? ?br? |
| 44 | '\" Begin vertical sidebar, for use in marking newly-changed parts |
| 45 | '\" of man pages. The first argument is ignored and used for recording |
| 46 | '\" the version when the .VS was added, so that the sidebars can be |
| 47 | '\" found and removed when they reach a certain age. If another argument |
| 48 | '\" is present, then a line break is forced before starting the sidebar. |
| 49 | '\" |
| 50 | '\" .VE |
| 51 | '\" End of vertical sidebar. |
| 52 | '\" |
| 53 | '\" .DS |
| 54 | '\" Begin an indented unfilled display. |
| 55 | '\" |
| 56 | '\" .DE |
| 57 | '\" End of indented unfilled display. |
| 58 | '\" |
| 59 | '\" .SO |
| 60 | '\" Start of list of standard options for a Tk widget. The |
| 61 | '\" options follow on successive lines, in four columns separated |
| 62 | '\" by tabs. |
| 63 | '\" |
| 64 | '\" .SE |
| 65 | '\" End of list of standard options for a Tk widget. |
| 66 | '\" |
| 67 | '\" .OP cmdName dbName dbClass |
| 68 | '\" Start of description of a specific option. cmdName gives the |
| 69 | '\" option's name as specified in the class command, dbName gives |
| 70 | '\" the option's name in the option database, and dbClass gives |
| 71 | '\" the option's class in the option database. |
| 72 | '\" |
| 73 | '\" .UL arg1 arg2 |
| 74 | '\" Print arg1 underlined, then print arg2 normally. |
| 75 | '\" |
| 76 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| 77 | '\" |
| 78 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| 79 | .if t .wh -1.3i ^B |
| 80 | .nr ^l \n(.l |
| 81 | .ad b |
| 82 | '\" # Start an argument description |
| 83 | .de AP |
| 84 | .ie !"\\$4"" .TP \\$4 |
| 85 | .el \{\ |
| 86 | . ie !"\\$2"" .TP \\n()Cu |
| 87 | . el .TP 15 |
| 88 | .\} |
| 89 | .ta \\n()Au \\n()Bu |
| 90 | .ie !"\\$3"" \{\ |
| 91 | \&\\$1 \\fI\\$2\\fP (\\$3) |
| 92 | .\".b |
| 93 | .\} |
| 94 | .el \{\ |
| 95 | .br |
| 96 | .ie !"\\$2"" \{\ |
| 97 | \&\\$1 \\fI\\$2\\fP |
| 98 | .\} |
| 99 | .el \{\ |
| 100 | \&\\fI\\$1\\fP |
| 101 | .\} |
| 102 | .\} |
| 103 | .. |
| 104 | '\" # define tabbing values for .AP |
| 105 | .de AS |
| 106 | .nr )A 10n |
| 107 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| 108 | .nr )B \\n()Au+15n |
| 109 | .\" |
| 110 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| 111 | .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| 112 | .. |
| 113 | .AS Tcl_Interp Tcl_CreateInterp in/out |
| 114 | '\" # BS - start boxed text |
| 115 | '\" # ^y = starting y location |
| 116 | '\" # ^b = 1 |
| 117 | .de BS |
| 118 | .br |
| 119 | .mk ^y |
| 120 | .nr ^b 1u |
| 121 | .if n .nf |
| 122 | .if n .ti 0 |
| 123 | .if n \l'\\n(.lu\(ul' |
| 124 | .if n .fi |
| 125 | .. |
| 126 | '\" # BE - end boxed text (draw box now) |
| 127 | .de BE |
| 128 | .nf |
| 129 | .ti 0 |
| 130 | .mk ^t |
| 131 | .ie n \l'\\n(^lu\(ul' |
| 132 | .el \{\ |
| 133 | .\" Draw four-sided box normally, but don't draw top of |
| 134 | .\" box if the box started on an earlier page. |
| 135 | .ie !\\n(^b-1 \{\ |
| 136 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 137 | .\} |
| 138 | .el \}\ |
| 139 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 140 | .\} |
| 141 | .\} |
| 142 | .fi |
| 143 | .br |
| 144 | .nr ^b 0 |
| 145 | .. |
| 146 | '\" # VS - start vertical sidebar |
| 147 | '\" # ^Y = starting y location |
| 148 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| 149 | .de VS |
| 150 | .if !"\\$2"" .br |
| 151 | .mk ^Y |
| 152 | .ie n 'mc \s12\(br\s0 |
| 153 | .el .nr ^v 1u |
| 154 | .. |
| 155 | '\" # VE - end of vertical sidebar |
| 156 | .de VE |
| 157 | .ie n 'mc |
| 158 | .el \{\ |
| 159 | .ev 2 |
| 160 | .nf |
| 161 | .ti 0 |
| 162 | .mk ^t |
| 163 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| 164 | .sp -1 |
| 165 | .fi |
| 166 | .ev |
| 167 | .\} |
| 168 | .nr ^v 0 |
| 169 | .. |
| 170 | '\" # Special macro to handle page bottom: finish off current |
| 171 | '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| 172 | '\" # page bottom macro. |
| 173 | .de ^B |
| 174 | .ev 2 |
| 175 | 'ti 0 |
| 176 | 'nf |
| 177 | .mk ^t |
| 178 | .if \\n(^b \{\ |
| 179 | .\" Draw three-sided box if this is the box's first page, |
| 180 | .\" draw two sides but no top otherwise. |
| 181 | .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 |
| 182 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| 183 | .\} |
| 184 | .if \\n(^v \{\ |
| 185 | .nr ^x \\n(^tu+1v-\\n(^Yu |
| 186 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| 187 | .\} |
| 188 | .bp |
| 189 | 'fi |
| 190 | .ev |
| 191 | .if \\n(^b \{\ |
| 192 | .mk ^y |
| 193 | .nr ^b 2 |
| 194 | .\} |
| 195 | .if \\n(^v \{\ |
| 196 | .mk ^Y |
| 197 | .\} |
| 198 | .. |
| 199 | '\" # DS - begin display |
| 200 | .de DS |
| 201 | .RS |
| 202 | .nf |
| 203 | .sp |
| 204 | .. |
| 205 | '\" # DE - end display |
| 206 | .de DE |
| 207 | .fi |
| 208 | .RE |
| 209 | .sp |
| 210 | .. |
| 211 | '\" # SO - start of list of standard options |
| 212 | .de SO |
| 213 | .SH "STANDARD OPTIONS" |
| 214 | .LP |
| 215 | .nf |
| 216 | .ta 5.5c 11c |
| 217 | .ft B |
| 218 | .. |
| 219 | '\" # SE - end of list of standard options |
| 220 | .de SE |
| 221 | .fi |
| 222 | .ft R |
| 223 | .LP |
| 224 | See the \\fBoptions\\fR manual entry for details on the standard options. |
| 225 | .. |
| 226 | '\" # OP - start of full description for a single option |
| 227 | .de OP |
| 228 | .LP |
| 229 | .nf |
| 230 | .ta 4c |
| 231 | Command-Line Name: \\fB\\$1\\fR |
| 232 | Database Name: \\fB\\$2\\fR |
| 233 | Database Class: \\fB\\$3\\fR |
| 234 | .fi |
| 235 | .IP |
| 236 | .. |
| 237 | '\" # CS - begin code excerpt |
| 238 | .de CS |
| 239 | .RS |
| 240 | .nf |
| 241 | .ta .25i .5i .75i 1i |
| 242 | .. |
| 243 | '\" # CE - end code excerpt |
| 244 | .de CE |
| 245 | .fi |
| 246 | .RE |
| 247 | .. |
| 248 | .de UL |
| 249 | \\$1\l'|0\(ul'\\$2 |
| 250 | .. |
| 251 | .TH clock n 8.4 Tcl "Tcl Built-In Commands" |
| 252 | .BS |
| 253 | '\" Note: do not modify the .SH NAME line immediately below! |
| 254 | .SH NAME |
| 255 | clock \- Obtain and manipulate time |
| 256 | .SH SYNOPSIS |
| 257 | \fBclock \fIoption\fR ?\fIarg arg ...\fR? |
| 258 | .BE |
| 259 | |
| 260 | .SH DESCRIPTION |
| 261 | .PP |
| 262 | This command performs one of several operations that may obtain |
| 263 | or manipulate strings or values that represent some notion of |
| 264 | time. The \fIoption\fR argument determines what action is carried |
| 265 | out by the command. The legal \fIoptions\fR (which may be |
| 266 | abbreviated) are: |
| 267 | .VS 8.3 |
| 268 | .TP |
| 269 | \fBclock clicks\fR ?\fB\-milliseconds\fR? |
| 270 | Return a high-resolution time value as a system-dependent integer |
| 271 | value. The unit of the value is system-dependent but should be the |
| 272 | highest resolution clock available on the system such as a CPU cycle |
| 273 | counter. If \fB\-milliseconds\fR is specified, then the value is |
| 274 | guaranteed to be of millisecond granularity. |
| 275 | This value should only be used for the relative measurement |
| 276 | of elapsed time. |
| 277 | .VE 8.3 |
| 278 | .TP |
| 279 | \fBclock format \fIclockValue\fR ?\fB\-format \fIstring\fR? ?\fB\-gmt \fIboolean\fR? |
| 280 | Converts an integer time value, typically returned by |
| 281 | \fBclock seconds\fR, \fBclock scan\fR, or the \fBatime\fR or \fBmtime\fR |
| 282 | options of the \fBfile\fR command, to human-readable |
| 283 | form. If the \fB\-format\fR argument is present the next argument is a |
| 284 | string that describes how the date and time are to be formatted. |
| 285 | Field descriptors consist of a \fB%\fR followed by a field |
| 286 | descriptor character. All other characters are copied into the result. |
| 287 | Valid field descriptors are: |
| 288 | .RS |
| 289 | .IP \fB%%\fR |
| 290 | Insert a %. |
| 291 | .IP \fB%a\fR |
| 292 | Abbreviated weekday name (Mon, Tue, etc.). |
| 293 | .IP \fB%A\fR |
| 294 | Full weekday name (Monday, Tuesday, etc.). |
| 295 | .IP \fB%b\fR |
| 296 | Abbreviated month name (Jan, Feb, etc.). |
| 297 | .IP \fB%B\fR |
| 298 | Full month name. |
| 299 | .VS 8.4 |
| 300 | .IP \fB%c\fR |
| 301 | Locale specific date and time. The format for date and time |
| 302 | in the default "C" locale on Unix/Mac is "%a %b %d %H:%M:%S %Y". |
| 303 | On Windows, this value is the locale specific long date and time, as |
| 304 | specified in the Regional Options control panel settings. |
| 305 | .IP \fB%C\fR |
| 306 | First two digits of the four-digit year (19 or 20). |
| 307 | .VE 8.4 |
| 308 | .IP \fB%d\fR |
| 309 | Day of month (01 - 31). |
| 310 | .VS 8.4 |
| 311 | '\" Since the inclusion of compat/strftime.c, %D, %e, %h should work on all |
| 312 | '\" platforms. |
| 313 | .IP \fB%D\fR |
| 314 | Date as %m/%d/%y. |
| 315 | .IP \fB%e\fR |
| 316 | Day of month (1 - 31), no leading zeros. |
| 317 | .IP \fB%g\fR |
| 318 | The ISO8601 year number corresponding to the ISO8601 week (%V), expressed |
| 319 | as a two-digit year-of-the-century, with leading zero if necessary. |
| 320 | .IP \fB%G\fR |
| 321 | The ISO8601 year number corresponding to the ISO8601 week (%V), expressed |
| 322 | as a four-digit number. |
| 323 | .IP \fB%h\fR |
| 324 | Abbreviated month name. |
| 325 | .VE 8.4 |
| 326 | .IP \fB%H\fR |
| 327 | Hour in 24-hour format (00 - 23). |
| 328 | .VS 8.4 |
| 329 | .IP \fB%I\fR |
| 330 | Hour in 12-hour format (01 - 12). |
| 331 | .VE 8.4 |
| 332 | .IP \fB%j\fR |
| 333 | Day of year (001 - 366). |
| 334 | .VS 8.4 |
| 335 | .IP \fB%k\fR |
| 336 | Hour in 24-hour format, without leading zeros (0 - 23). |
| 337 | .IP \fB%l\fR |
| 338 | Hour in 12-hour format, without leading zeros (1 - 12). |
| 339 | .VE 8.4 |
| 340 | .IP \fB%m\fR |
| 341 | Month number (01 - 12). |
| 342 | .IP \fB%M\fR |
| 343 | Minute (00 - 59). |
| 344 | .VS 8.4 |
| 345 | .IP \fB%n\fR |
| 346 | Insert a newline. |
| 347 | .VE 8.4 |
| 348 | .IP \fB%p\fR |
| 349 | AM/PM indicator. |
| 350 | .VS 8.4 |
| 351 | .IP \fB%r\fR |
| 352 | Time in a locale-specific "meridian" format. The "meridian" |
| 353 | format in the default "C" locale is "%I:%M:%S %p". |
| 354 | .IP \fB%R\fR |
| 355 | Time as %H:%M. |
| 356 | .IP \fB%s\fR |
| 357 | Count of seconds since the epoch, expressed as a decimal integer. |
| 358 | .VE 8.4 |
| 359 | .IP \fB%S\fR |
| 360 | Seconds (00 - 59). |
| 361 | .VS 8.4 |
| 362 | .IP \fB%t\fR |
| 363 | Insert a tab. |
| 364 | .IP \fB%T\fR |
| 365 | Time as %H:%M:%S. |
| 366 | .IP \fB%u\fR |
| 367 | Weekday number (Monday = 1, Sunday = 7). |
| 368 | .VE 8.4 |
| 369 | .IP \fB%U\fR |
| 370 | Week of year (00 - 52), Sunday is the first day of the week. |
| 371 | .VS 8.4 |
| 372 | .IP \fB%V\fR |
| 373 | Week of year according to ISO-8601 rules. Week 1 of a given |
| 374 | year is the week containing 4 January. |
| 375 | .IP \fB%w\fR |
| 376 | Weekday number (Sunday = 0, Saturday = 6). |
| 377 | .VE 8.4 |
| 378 | .IP \fB%W\fR |
| 379 | Week of year (00 - 52), Monday is the first day of the week. |
| 380 | .VS 8.4 |
| 381 | .IP \fB%x\fR |
| 382 | Locale specific date format. The format for a date in the default "C" |
| 383 | locale for Unix/Mac is "%m/%d/%y". |
| 384 | On Windows, this value is the locale specific short date format, as |
| 385 | specified in the Regional Options control panel settings. |
| 386 | .IP \fB%X\fR |
| 387 | Locale specific 24-hour time format. The format for a |
| 388 | 24-hour time in the default "C" locale for Unix/Mac is "%H:%M:%S". |
| 389 | On Windows, this value is the locale specific time format, as |
| 390 | specified in the Regional Options control panel settings. |
| 391 | .VE 8.4 |
| 392 | .IP \fB%y\fR |
| 393 | Year without century (00 - 99). |
| 394 | .IP \fB%Y\fR |
| 395 | Year with century (e.g. 1990) |
| 396 | .IP \fB%Z\fR |
| 397 | Time zone name. |
| 398 | .RE |
| 399 | .VS 8.4 |
| 400 | .sp |
| 401 | '\" All the field descriptors should be portable now that |
| 402 | '\" compat/strftime.c is in place, with the possible exception |
| 403 | '\" of the time zone name. |
| 404 | '\".RS |
| 405 | '\"In addition, the following field descriptors may be supported on some |
| 406 | '\"systems (e.g. Unix but not Windows): |
| 407 | '\".IP \fB%D\fR |
| 408 | '\"Date as %m/%d/%y. |
| 409 | '\".IP \fB%e\fR |
| 410 | '\"Day of month (1 - 31), no leading zeros. |
| 411 | '\".IP \fB%h\fR |
| 412 | '\"Abbreviated month name. |
| 413 | '\".IP \fB%n\fR |
| 414 | '\"Insert a newline. |
| 415 | '\".IP \fB%r\fR |
| 416 | '\"Time as %I:%M:%S %p. |
| 417 | '\".IP \fB%R\fR |
| 418 | '\"Time as %H:%M. |
| 419 | '\".IP \fB%t\fR |
| 420 | '\"Insert a tab. |
| 421 | '\".IP \fB%T\fR |
| 422 | '\"Time as %H:%M:%S. |
| 423 | '\".RE |
| 424 | '\".sp |
| 425 | .VE 8.4 |
| 426 | .RS |
| 427 | If the \fB\-format\fR argument is not specified, the format string |
| 428 | \fB"%a %b %d %H:%M:%S %Z %Y"\fR is used. If the \fB\-gmt\fR argument |
| 429 | is present the next argument must be a boolean which if true specifies |
| 430 | that the time will be formatted as Greenwich Mean Time. If false |
| 431 | then the local timezone will be used as defined by the operating |
| 432 | environment. |
| 433 | .RE |
| 434 | .TP |
| 435 | \fBclock scan \fIdateString\fR ?\fB\-base \fIclockVal\fR? ?\fB\-gmt \fIboolean\fR? |
| 436 | Convert \fIdateString\fR to an integer clock value (see \fBclock seconds\fR). |
| 437 | This command can parse and convert virtually any standard date and/or time |
| 438 | string, which can include standard time zone mnemonics. If only a time is |
| 439 | specified, the current date is assumed. If the string does not contain a |
| 440 | time zone mnemonic, the local time zone is assumed, unless the \fB\-gmt\fR |
| 441 | argument is true, in which case the clock value is calculated assuming |
| 442 | that the specified time is relative to Greenwich Mean Time. |
| 443 | \fB-gmt\fR, if specified, affects only the computed time value; it does not |
| 444 | impact the interpretation of \fB-base\fR. |
| 445 | .sp |
| 446 | If the \fB\-base\fR flag is specified, the next argument should contain |
| 447 | an integer clock value. Only the date in this value is used, not the |
| 448 | time. This is useful for determining the time on a specific day or |
| 449 | doing other date-relative conversions. |
| 450 | .sp |
| 451 | The \fIdateString\fR consists of zero or more specifications of the |
| 452 | following form: |
| 453 | .RS |
| 454 | .TP |
| 455 | \fItime\fR |
| 456 | A time of day, which is of the form: \fIhh\fR?\fI:mm\fR?\fI:ss\fR?? |
| 457 | ?\fImeridian\fR? ?\fIzone\fR? or \fIhhmm \fR?\fImeridian\fR? |
| 458 | ?\fIzone\fR?. If no meridian is specified, \fIhh\fR is interpreted on |
| 459 | a 24-hour clock. |
| 460 | .TP |
| 461 | \fIdate\fR |
| 462 | A specific month and day with optional year. The |
| 463 | acceptable formats are \fImm/dd\fR?\fI/yy\fR?, \fImonthname dd\fR |
| 464 | ?, \fIyy\fR?, \fIdd monthname \fR?\fIyy\fR?, \fIday, dd monthname |
| 465 | yy\fR, \fI?CC?yymmdd\fR, \fI?CC?yy-mm-dd\fR, \fIdd-monthname-?CC?yy\fR. |
| 466 | The default year is the current year. If the year is less |
| 467 | .VS |
| 468 | than 100, we treat the years 00-68 as 2000-2068 and the years 69-99 |
| 469 | as 1969-1999. Not all platforms can represent the years 38-70, so |
| 470 | an error may result if these years are used. |
| 471 | .VE |
| 472 | .TP |
| 473 | \fIISO 8601 point-in-time\fR |
| 474 | An ISO 8601 point-in-time specification, such as \fICCyymmddThhmmss\fR, where |
| 475 | T is the literal T, \fICCyymmdd hhmmss\fR, or |
| 476 | \fICCyymmddThh:mm:ss\fR. Note that only these three formats are accepted. |
| 477 | The command does \fInot\fR accept the full range of point-in-time |
| 478 | specifications specified in ISO8601. Other formats can be recognized by |
| 479 | using commands such as \fBregexp\fR to extract their fields and reorganize |
| 480 | them into a form accepted by the \fBclock scan\fR command. |
| 481 | .TP |
| 482 | \fIrelative time\fR |
| 483 | A specification relative to the current time. The format is \fInumber |
| 484 | unit\fR acceptable units are \fByear\fR, \fBfortnight\fR, \fBmonth\fR, \fBweek\fR, \fBday\fR, |
| 485 | \fBhour\fR, \fBminute\fR (or \fBmin\fR), and \fBsecond\fR (or \fBsec\fR). The |
| 486 | unit can be specified as a singular or plural, as in \fB3 weeks\fR. |
| 487 | These modifiers may also be specified: |
| 488 | \fBtomorrow\fR, \fByesterday\fR, \fBtoday\fR, \fBnow\fR, |
| 489 | \fBlast\fR, \fBthis\fR, \fBnext\fR, \fBago\fR. |
| 490 | .RE |
| 491 | .sp |
| 492 | .RS |
| 493 | The actual date is calculated according to the following steps. |
| 494 | First, any absolute date and/or time is processed and converted. |
| 495 | Using that time as the base, day-of-week specifications are added. |
| 496 | Next, relative specifications are used. If a date or day is |
| 497 | specified, and no absolute or relative time is given, midnight is |
| 498 | used. Finally, a correction is applied so that the correct hour of |
| 499 | the day is produced after allowing for daylight savings time |
| 500 | differences and the correct date is given when going from the end |
| 501 | of a long month to a short month. |
| 502 | .sp |
| 503 | Daylight savings time correction is applied only when the relative time |
| 504 | is specified in units of days or more, ie, days, weeks, fortnights, months or |
| 505 | years. This means that when crossing the daylight savings time boundary, |
| 506 | different results will be given for \fBclock scan "1 day"\fR and |
| 507 | \fBclock scan "24 hours"\fR: |
| 508 | .CS |
| 509 | .ta 6c |
| 510 | % \fBclock scan\fR "1 day" -base [\fBclock scan\fR 1999-10-31] |
| 511 | 941443200 |
| 512 | % \fBclock scan\fR "24 hours" -base [\fBclock scan\fR 1999-10-31] |
| 513 | 941439600 |
| 514 | .CE |
| 515 | .RE |
| 516 | .TP |
| 517 | \fBclock seconds\fR |
| 518 | Return the current date and time as a system-dependent integer value. The |
| 519 | unit of the value is seconds, allowing it to be used for relative time |
| 520 | calculations. The value is usually defined as total elapsed time from |
| 521 | an ``epoch''. You shouldn't assume the value of the epoch. |
| 522 | |
| 523 | .SH "SEE ALSO" |
| 524 | date(1), time(n) |
| 525 | |
| 526 | .SH KEYWORDS |
| 527 | clock, date, time |