1.\" $OpenBSD: roff.7,v 1.92 2019/04/21 22:43:00 schwarze Exp $ 2.\" 3.\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv> 4.\" Copyright (c) 2010-2019 Ingo Schwarze <schwarze@openbsd.org> 5.\" 6.\" Permission to use, copy, modify, and distribute this software for any 7.\" purpose with or without fee is hereby granted, provided that the above 8.\" copyright notice and this permission notice appear in all copies. 9.\" 10.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17.\" 18.Dd $Mdocdate: April 21 2019 $ 19.Dt ROFF 7 20.Os 21.Sh NAME 22.Nm roff 23.Nd roff language reference for mandoc 24.Sh DESCRIPTION 25The 26.Nm roff 27language is a general purpose text formatting language. 28Since traditional implementations of the 29.Xr mdoc 7 30and 31.Xr man 7 32manual formatting languages are based on it, 33many real-world manuals use small numbers of 34.Nm 35requests and escape sequences intermixed with their 36.Xr mdoc 7 37or 38.Xr man 7 39code. 40To properly format such manuals, the 41.Xr mandoc 1 42utility supports a subset of 43.Nm 44requests and escapes. 45Even though this manual page lists all 46.Nm 47requests and escape sequences, it only contains partial information 48about requests not supported by 49.Xr mandoc 1 50and about language features that do not matter for manual pages. 51For complete 52.Nm 53manuals, consult the 54.Sx SEE ALSO 55section. 56.Pp 57Input lines beginning with the control character 58.Sq \&. 59are parsed for requests and macros. 60Such lines are called 61.Dq request lines 62or 63.Dq macro lines , 64respectively. 65Requests change the processing state and manipulate the formatting; 66some macros also define the document structure and produce formatted 67output. 68The single quote 69.Pq Qq \(aq 70is accepted as an alternative control character, 71treated by 72.Xr mandoc 1 73just like 74.Ql \&. 75.Pp 76Lines not beginning with control characters are called 77.Dq text lines . 78They provide free-form text to be printed; the formatting of the text 79depends on the respective processing context. 80.Sh LANGUAGE SYNTAX 81.Nm 82documents may contain only graphable 7-bit ASCII characters, the space 83character, and, in certain circumstances, the tab character. 84The backslash character 85.Sq \e 86indicates the start of an escape sequence, used for example for 87.Sx Comments 88and 89.Sx Special Characters . 90For a complete listing of escape sequences, consult the 91.Sx ESCAPE SEQUENCE REFERENCE 92below. 93.Ss Comments 94Text following an escaped double-quote 95.Sq \e\(dq , 96whether in a request, macro, or text line, is ignored to the end of the line. 97A request line beginning with a control character and comment escape 98.Sq \&.\e\(dq 99is also ignored. 100Furthermore, request lines with only a control character and optional 101trailing whitespace are stripped from input. 102.Pp 103Examples: 104.Bd -literal -offset indent -compact 105\&.\e\(dq This is a comment line. 106\&.\e\(dq The next line is ignored: 107\&. 108\&.Sh EXAMPLES \e\(dq This is a comment, too. 109\&example text \e\(dq And so is this. 110.Ed 111.Ss Special Characters 112Special characters are used to encode special glyphs and are rendered 113differently across output media. 114They may occur in request, macro, and text lines. 115Sequences begin with the escape character 116.Sq \e 117followed by either an open-parenthesis 118.Sq \&( 119for two-character sequences; an open-bracket 120.Sq \&[ 121for n-character sequences (terminated at a close-bracket 122.Sq \&] ) ; 123or a single one character sequence. 124.Pp 125Examples: 126.Bl -tag -width Ds -offset indent -compact 127.It Li \e(em 128Two-letter em dash escape. 129.It Li \ee 130One-letter backslash escape. 131.El 132.Pp 133See 134.Xr mandoc_char 7 135for a complete list. 136.Ss Font Selection 137In 138.Xr mdoc 7 139and 140.Xr man 7 141documents, fonts are usually selected with macros. 142The 143.Ic \ef 144escape sequence and the 145.Ic \&ft 146request can be used to manually change the font, 147but this is not recommended in 148.Xr mdoc 7 149documents. 150Such manual font changes are overridden by many subsequent macros. 151.Pp 152The following fonts are supported: 153.Pp 154.Bl -tag -width CW -offset indent -compact 155.It Cm B 156Bold font. 157.It Cm BI 158A font that is both bold and italic. 159.It Cm CB 160Bold constant width font. 161Same as 162.Cm B 163in terminal output. 164.It Cm CI 165Italic constant width font. 166Same as 167.Cm I 168in terminal output. 169.It Cm CR 170Regular constant width font. 171Same as 172.Cm R 173in terminal output. 174.It Cm CW 175An alias for 176.Cm CR . 177.It Cm I 178Italic font. 179.It Cm P 180Return to the previous font. 181If a macro caused a font change since the last 182.Ic \ef 183eascape sequence or 184.Ic \&ft 185request, this returns to the font before the last font change in 186the macro rather than to the font before the last manual font change. 187.It Cm R 188Roman font. 189This is the default font. 190.It Cm 1 191An alias for 192.Cm R . 193.It Cm 2 194An alias for 195.Cm I . 196.It Cm 3 197An alias for 198.Cm B . 199.It Cm 4 200An alias for 201.Cm BI . 202.El 203.Pp 204Examples: 205.Bl -tag -width Ds -offset indent -compact 206.It Li \efBbold\efR 207Write in \fBbold\fP, then switch to regular font mode. 208.It Li \efIitalic\efP 209Write in \fIitalic\fP, then return to previous font mode. 210.It Li \ef(BIbold italic\efP 211Write in \f(BIbold italic\fP, then return to previous font mode. 212.El 213.Ss Whitespace 214Whitespace consists of the space character. 215In text lines, whitespace is preserved within a line. 216In request and macro lines, whitespace delimits arguments and is discarded. 217.Pp 218Unescaped trailing spaces are stripped from text line input unless in a 219literal context. 220In general, trailing whitespace on any input line is discouraged for 221reasons of portability. 222In the rare case that a space character is needed at the end of an 223input line, it may be forced by 224.Sq \e\ \e& . 225.Pp 226Literal space characters can be produced in the output 227using escape sequences. 228In macro lines, they can also be included in arguments using quotation; see 229.Sx MACRO SYNTAX 230for details. 231.Pp 232Blank text lines, which may include whitespace, are only permitted 233within literal contexts. 234If the first character of a text line is a space, that line is printed 235with a leading newline. 236.Ss Scaling Widths 237Many requests and macros support scaled widths for their arguments. 238The syntax for a scaled width is 239.Sq Li [+-]?[0-9]*.[0-9]*[:unit:] , 240where a decimal must be preceded or followed by at least one digit. 241.Pp 242The following scaling units are accepted: 243.Pp 244.Bl -tag -width Ds -offset indent -compact 245.It c 246centimetre 247.It i 248inch 249.It P 250pica (1/6 inch) 251.It p 252point (1/72 inch) 253.It f 254scale 255.Sq u 256by 65536 257.It v 258default vertical span 259.It m 260width of rendered 261.Sq m 262.Pq em 263character 264.It n 265width of rendered 266.Sq n 267.Pq en 268character 269.It u 270default horizontal span for the terminal 271.It M 272mini-em (1/100 em) 273.El 274.Pp 275Using anything other than 276.Sq m , 277.Sq n , 278or 279.Sq v 280is necessarily non-portable across output media. 281See 282.Sx COMPATIBILITY . 283.Pp 284If a scaling unit is not provided, the numerical value is interpreted 285under the default rules of 286.Sq v 287for vertical spaces and 288.Sq u 289for horizontal ones. 290.Pp 291Examples: 292.Bl -tag -width ".Bl -tag -width 2i" -offset indent -compact 293.It Li \&.Bl -tag -width 2i 294two-inch tagged list indentation in 295.Xr mdoc 7 296.It Li \&.HP 2i 297two-inch tagged list indentation in 298.Xr man 7 299.It Li \&.sp 2v 300two vertical spaces 301.El 302.Ss Sentence Spacing 303Each sentence should terminate at the end of an input line. 304By doing this, a formatter will be able to apply the proper amount of 305spacing after the end of sentence (unescaped) period, exclamation mark, 306or question mark followed by zero or more non-sentence closing 307delimiters 308.Po 309.Sq \&) , 310.Sq \&] , 311.Sq \&' , 312.Sq \&" 313.Pc . 314.Pp 315The proper spacing is also intelligently preserved if a sentence ends at 316the boundary of a macro line. 317.Pp 318Examples: 319.Bd -literal -offset indent -compact 320Do not end sentences mid-line like this. Instead, 321end a sentence like this. 322A macro would end like this: 323\&.Xr mandoc 1 \&. 324.Ed 325.Sh REQUEST SYNTAX 326A request or macro line consists of: 327.Pp 328.Bl -enum -compact 329.It 330the control character 331.Sq \&. 332or 333.Sq \(aq 334at the beginning of the line, 335.It 336optionally an arbitrary amount of whitespace, 337.It 338the name of the request or the macro, which is one word of arbitrary 339length, terminated by whitespace, 340.It 341and zero or more arguments delimited by whitespace. 342.El 343.Pp 344Thus, the following request lines are all equivalent: 345.Bd -literal -offset indent 346\&.ig end 347\&.ig end 348\&. ig end 349.Ed 350.Sh MACRO SYNTAX 351Macros are provided by the 352.Xr mdoc 7 353and 354.Xr man 7 355languages and can be defined by the 356.Ic \&de 357request. 358When called, they follow the same syntax as requests, except that 359macro arguments may optionally be quoted by enclosing them 360in double quote characters 361.Pq Sq \(dq . 362Quoted text, even if it contains whitespace or would cause 363a macro invocation when unquoted, is always considered literal text. 364Inside quoted text, pairs of double quote characters 365.Pq Sq Qq 366resolve to single double quote characters. 367.Pp 368To be recognised as the beginning of a quoted argument, the opening 369quote character must be preceded by a space character. 370A quoted argument extends to the next double quote character that is not 371part of a pair, or to the end of the input line, whichever comes earlier. 372Leaving out the terminating double quote character at the end of the line 373is discouraged. 374For clarity, if more arguments follow on the same input line, 375it is recommended to follow the terminating double quote character 376by a space character; in case the next character after the terminating 377double quote character is anything else, it is regarded as the beginning 378of the next, unquoted argument. 379.Pp 380Both in quoted and unquoted arguments, pairs of backslashes 381.Pq Sq \e\e 382resolve to single backslashes. 383In unquoted arguments, space characters can alternatively be included 384by preceding them with a backslash 385.Pq Sq \e\~ , 386but quoting is usually better for clarity. 387.Pp 388Examples: 389.Bl -tag -width Ds -offset indent -compact 390.It Li .Fn strlen \(dqconst char *s\(dq 391Group arguments 392.Qq const char *s 393into one function argument. 394If unspecified, 395.Qq const , 396.Qq char , 397and 398.Qq *s 399would be considered separate arguments. 400.It Li .Op \(dqFl a\(dq 401Consider 402.Qq \&Fl a 403as literal text instead of a flag macro. 404.El 405.Sh REQUEST REFERENCE 406The 407.Xr mandoc 1 408.Nm 409parser recognises the following requests. 410For requests marked as "ignored" or "unsupported", any arguments are 411ignored, and the number of arguments is not checked. 412.Bl -tag -width Ds 413.It Ic \&ab Op Ar message 414Abort processing. 415Currently unsupported. 416.It Ic \&ad Op Cm b | c | l | n | r 417Set line adjustment mode for subsequent text. 418Currently ignored. 419.It Ic \&af Ar registername format 420Assign an output format to a number register. 421Currently ignored. 422.It Ic \&aln Ar newname oldname 423Create an alias for a number register. 424Currently unsupported. 425.It Ic \&als Ar newname oldname 426Create an alias for a request, string, macro, or diversion. 427.It Ic \&am Ar macroname Op Ar endmacro 428Append to a macro definition. 429The syntax of this request is the same as that of 430.Ic \&de . 431.It Ic \&am1 Ar macroname Op Ar endmacro 432Append to a macro definition, switching roff compatibility mode off 433during macro execution (groff extension). 434The syntax of this request is the same as that of 435.Ic \&de1 . 436Since 437.Xr mandoc 1 438does not implement 439.Nm 440compatibility mode at all, it handles this request as an alias for 441.Ic \&am . 442.It Ic \&ami Ar macrostring Op Ar endstring 443Append to a macro definition, specifying the macro name indirectly 444(groff extension). 445The syntax of this request is the same as that of 446.Ic \&dei . 447.It Ic \&ami1 Ar macrostring Op Ar endstring 448Append to a macro definition, specifying the macro name indirectly 449and switching roff compatibility mode off during macro execution 450(groff extension). 451The syntax of this request is the same as that of 452.Ic \&dei1 . 453Since 454.Xr mandoc 1 455does not implement 456.Nm 457compatibility mode at all, it handles this request as an alias for 458.Ic \&ami . 459.It Ic \&as Ar stringname Op Ar string 460Append to a user-defined string. 461The syntax of this request is the same as that of 462.Ic \&ds . 463If a user-defined string with the specified name does not yet exist, 464it is set to the empty string before appending. 465.It Ic \&as1 Ar stringname Op Ar string 466Append to a user-defined string, switching roff compatibility mode off 467during macro execution (groff extension). 468The syntax of this request is the same as that of 469.Ic \&ds1 . 470Since 471.Xr mandoc 1 472does not implement 473.Nm 474compatibility mode at all, it handles this request as an alias for 475.Ic \&as . 476.It Ic \&asciify Ar divname 477Fully unformat a diversion. 478Currently unsupported. 479.It Ic \&backtrace 480Print a backtrace of the input stack. 481This is a groff extension and currently ignored. 482.It Ic \&bd Ar font Oo Ar curfont Oc Op Ar offset 483Artificially embolden by repeated printing with small shifts. 484Currently ignored. 485.It Ic \&bleedat Ar left top width height 486Set the BleedBox page parameter for PDF generation. 487This is a Heirloom extension and currently ignored. 488.It Ic \&blm Ar macroname 489Set a blank line trap. 490Currently unsupported. 491.It Ic \&box Ar divname 492Begin a diversion without including a partially filled line. 493Currently unsupported. 494.It Ic \&boxa Ar divname 495Add to a diversion without including a partially filled line. 496Currently unsupported. 497.It Ic \&bp Oo Cm + Ns | Ns Cm - Oc Ns Ar pagenumber 498Begin a new page. 499Currently ignored. 500.It Ic \&BP Ar source height width position offset flags label 501Define a frame and place a picture in it. 502This is a Heirloom extension and currently unsupported. 503.It Ic \&br 504Break the output line. 505.It Ic \&break 506Break out of the innermost 507.Ic \&while 508loop. 509.It Ic \&breakchar Ar char ... 510Optional line break characters. 511This is a Heirloom extension and currently ignored. 512.It Ic \&brnl Ar N 513Break output line after the next 514.Ar N 515input lines. 516This is a Heirloom extension and currently ignored. 517.It Ic \&brp 518Break and spread output line. 519Currently, this is implemented as an alias for 520.Ic \&br . 521.It Ic \&brpnl Ar N 522Break and spread output line after the next 523.Ar N 524input lines. 525This is a Heirloom extension and currently ignored. 526.It Ic \&c2 Op Ar char 527Change the no-break control character. 528Currently unsupported. 529.It Ic \&cc Op Ar char 530Change the control character. 531If 532.Ar char 533is not specified, the control character is reset to 534.Sq \&. . 535Trailing characters are ignored. 536.It Ic \&ce Op Ar N 537Center the next 538.Ar N 539input lines without filling. 540.Ar N 541defaults to 1. 542An argument of 0 or less ends centering. 543Currently, high level macros abort centering. 544.It Ic \&cf Ar filename 545Output the contents of a file. 546Ignored because insecure. 547.It Ic \&cflags Ar flags char ... 548Set character flags. 549This is a groff extension and currently ignored. 550.It Ic \&ch Ar macroname Op Ar dist 551Change a trap location. 552Currently ignored. 553.It Ic \&char Ar glyph Op Ar string 554Define or redefine the ASCII character or character escape sequence 555.Ar glyph 556to be rendered as 557.Ar string , 558which can be empty. 559Only partially supported in 560.Xr mandoc 1 ; 561may interact incorrectly with 562.Ic \&tr . 563.It Ic \&chop Ar stringname 564Remove the last character from a macro, string, or diversion. 565Currently unsupported. 566.It Ic \&class Ar classname char ... 567Define a character class. 568This is a groff extension and currently ignored. 569.It Ic \&close Ar streamname 570Close an open file. 571Ignored because insecure. 572.It Ic \&CL Ar color text 573Print text in color. 574This is a Heirloom extension and currently unsupported. 575.It Ic \&color Op Cm 1 | 0 576Activate or deactivate colors. 577This is a groff extension and currently ignored. 578.It Ic \&composite Ar from to 579Define a name component for composite glyph names. 580This is a groff extension and currently unsupported. 581.It Ic \&continue 582Immediately start the next iteration of a 583.Ic \&while 584loop. 585Currently unsupported. 586.It Ic \&cp Op Cm 1 | 0 587Switch 588.Nm 589compatibility mode on or off. 590Currently ignored. 591.It Ic \&cropat Ar left top width height 592Set the CropBox page parameter for PDF generation. 593This is a Heirloom extension and currently ignored. 594.It Ic \&cs Ar font Op Ar width Op Ar emsize 595Constant character spacing mode. 596Currently ignored. 597.It Ic \&cu Op Ar N 598Underline next 599.Ar N 600input lines including whitespace. 601Currently ignored. 602.It Ic \&da Ar divname 603Append to a diversion. 604Currently unsupported. 605.It Ic \&dch Ar macroname Op Ar dist 606Change a trap location in the current diversion. 607This is a Heirloom extension and currently unsupported. 608.It Ic \&de Ar macroname Op Ar endmacro 609Define a 610.Nm 611macro. 612Its syntax can be either 613.Bd -literal -offset indent 614.Pf . Ic \&de Ar macroname 615.Ar definition 616\&.. 617.Ed 618.Pp 619or 620.Bd -literal -offset indent 621.Pf . Ic \&de Ar macroname Ar endmacro 622.Ar definition 623.Pf . Ar endmacro 624.Ed 625.Pp 626Both forms define or redefine the macro 627.Ar macroname 628to represent the 629.Ar definition , 630which may consist of one or more input lines, including the newline 631characters terminating each line, optionally containing calls to 632.Nm 633requests, 634.Nm 635macros or high-level macros like 636.Xr man 7 637or 638.Xr mdoc 7 639macros, whichever applies to the document in question. 640.Pp 641Specifying a custom 642.Ar endmacro 643works in the same way as for 644.Ic \&ig ; 645namely, the call to 646.Sq Pf . Ar endmacro 647first ends the 648.Ar definition , 649and after that, it is also evaluated as a 650.Nm 651request or 652.Nm 653macro, but not as a high-level macro. 654.Pp 655The macro can be invoked later using the syntax 656.Pp 657.D1 Pf . Ar macroname Op Ar argument Op Ar argument ... 658.Pp 659Regarding argument parsing, see 660.Sx MACRO SYNTAX 661above. 662.Pp 663The line invoking the macro will be replaced 664in the input stream by the 665.Ar definition , 666replacing all occurrences of 667.No \e\e$ Ns Ar N , 668where 669.Ar N 670is a digit, by the 671.Ar N Ns th Ar argument . 672For example, 673.Bd -literal -offset indent 674\&.de ZN 675\efI\e^\e\e$1\e^\efP\e\e$2 676\&.. 677\&.ZN XtFree . 678.Ed 679.Pp 680produces 681.Pp 682.D1 \efI\e^XtFree\e^\efP. 683.Pp 684in the input stream, and thus in the output: \fI\^XtFree\^\fP. 685Each occurrence of \e\e$* is replaced with all the arguments, 686joined together with single space characters. 687The variant \e\e$@ is similar, except that each argument is 688individually quoted. 689.Pp 690Since macros and user-defined strings share a common string table, 691defining a macro 692.Ar macroname 693clobbers the user-defined string 694.Ar macroname , 695and the 696.Ar definition 697can also be printed using the 698.Sq \e* 699string interpolation syntax described below 700.Ic ds , 701but this is rarely useful because every macro definition contains at least 702one explicit newline character. 703.Pp 704In order to prevent endless recursion, both groff and 705.Xr mandoc 1 706limit the stack depth for expanding macros and strings 707to a large, but finite number, and 708.Xr mandoc 1 709also limits the length of the expanded input line. 710Do not rely on the exact values of these limits. 711.It Ic \&de1 Ar macroname Op Ar endmacro 712Define a 713.Nm 714macro that will be executed with 715.Nm 716compatibility mode switched off during macro execution. 717This is a groff extension. 718Since 719.Xr mandoc 1 720does not implement 721.Nm 722compatibility mode at all, it handles this request as an alias for 723.Ic \&de . 724.It Ic \&defcolor Ar newname scheme component ... 725Define a color name. 726This is a groff extension and currently ignored. 727.It Ic \&dei Ar macrostring Op Ar endstring 728Define a 729.Nm 730macro, specifying the macro name indirectly (groff extension). 731The syntax of this request is the same as that of 732.Ic \&de . 733The effect is the same as: 734.Pp 735.D1 Pf . Cm \&de No \e* Ns Bo Ar macrostring Bc Op \e* Ns Bq Ar endstring 736.It Ic \&dei1 Ar macrostring Op Ar endstring 737Define a 738.Nm 739macro that will be executed with 740.Nm 741compatibility mode switched off during macro execution, 742specifying the macro name indirectly (groff extension). 743Since 744.Xr mandoc 1 745does not implement 746.Nm 747compatibility mode at all, it handles this request as an alias for 748.Ic \&dei . 749.It Ic \&device Ar string ... 750.It Ic \&devicem Ar stringname 751These two requests only make sense with the groff-specific intermediate 752output format and are unsupported. 753.It Ic \&di Ar divname 754Begin a diversion. 755Currently unsupported. 756.It Ic \&do Ar command Op Ar argument ... 757Execute 758.Nm 759request or macro line with compatibility mode disabled. 760Currently unsupported. 761.It Ic \&ds Ar stringname Op Oo \(dq Oc Ns Ar string 762Define a user-defined string. 763The 764.Ar stringname 765and 766.Ar string 767arguments are space-separated. 768If the 769.Ar string 770begins with a double-quote character, that character will not be part 771of the string. 772All remaining characters on the input line form the 773.Ar string , 774including whitespace and double-quote characters, even trailing ones. 775.Pp 776The 777.Ar string 778can be interpolated into subsequent text by using 779.No \e* Ns Bq Ar stringname 780for a 781.Ar stringname 782of arbitrary length, or \e*(NN or \e*N if the length of 783.Ar stringname 784is two or one characters, respectively. 785Interpolation can be prevented by escaping the leading backslash; 786that is, an asterisk preceded by an even number of backslashes 787does not trigger string interpolation. 788.Pp 789Since user-defined strings and macros share a common string table, 790defining a string 791.Ar stringname 792clobbers the macro 793.Ar stringname , 794and the 795.Ar stringname 796used for defining a string can also be invoked as a macro, 797in which case the following input line will be appended to the 798.Ar string , 799forming a new input line passed to the 800.Nm 801parser. 802For example, 803.Bd -literal -offset indent 804\&.ds badidea .S 805\&.badidea 806H SYNOPSIS 807.Ed 808.Pp 809invokes the 810.Ic SH 811macro when used in a 812.Xr man 7 813document. 814Such abuse is of course strongly discouraged. 815.It Ic \&ds1 Ar stringname Op Oo \(dq Oc Ns Ar string 816Define a user-defined string that will be expanded with 817.Nm 818compatibility mode switched off during string expansion. 819This is a groff extension. 820Since 821.Xr mandoc 1 822does not implement 823.Nm 824compatibility mode at all, it handles this request as an alias for 825.Ic \&ds . 826.It Ic \&dwh Ar dist macroname 827Set a location trap in the current diversion. 828This is a Heirloom extension and currently unsupported. 829.It Ic \&dt Op Ar dist macroname 830Set a trap within a diversion. 831Currently unsupported. 832.It Ic \&ec Op Ar char 833Enable the escape mechanism and change the escape character. 834The 835.Ar char 836argument defaults to the backslash 837.Pq Sq \e . 838.It Ic \&ecr 839Restore the escape character. 840Currently unsupported. 841.It Ic \&ecs 842Save the escape character. 843Currently unsupported. 844.It Ic \&el Ar body 845The 846.Dq else 847half of an if/else conditional. 848Pops a result off the stack of conditional evaluations pushed by 849.Ic \&ie 850and uses it as its conditional. 851If no stack entries are present (e.g., due to no prior 852.Ic \&ie 853calls) 854then false is assumed. 855The syntax of this request is similar to 856.Ic \&if 857except that the conditional is missing. 858.It Ic \&em Ar macroname 859Set a trap at the end of input. 860Currently unsupported. 861.It Ic \&EN 862End an equation block. 863See 864.Ic \&EQ . 865.It Ic \&eo 866Disable the escape mechanism completely. 867.It Ic \&EP 868End a picture started by 869.Ic \&BP . 870This is a Heirloom extension and currently unsupported. 871.It Ic \&EQ 872Begin an equation block. 873See 874.Xr eqn 7 875for a description of the equation language. 876.It Ic \&errprint Ar message 877Print a string like an error message. 878This is a Heirloom extension and currently ignored. 879.It Ic \&ev Op Ar envname 880Switch to another environment. 881Currently unsupported. 882.It Ic \&evc Op Ar envname 883Copy an environment into the current environment. 884Currently unsupported. 885.It Ic \&ex 886Abort processing and exit. 887Currently unsupported. 888.It Ic \&fallback Ar curfont font ... 889Select the fallback sequence for a font. 890This is a Heirloom extension and currently ignored. 891.It Ic \&fam Op Ar familyname 892Change the font family. 893This is a groff extension and currently ignored. 894.It Ic \&fc Op Ar delimchar Op Ar padchar 895Define a delimiting and a padding character for fields. 896Currently unsupported. 897.It Ic \&fchar Ar glyphname Op Ar string 898Define a fallback glyph. 899Currently unsupported. 900.It Ic \&fcolor Ar colorname 901Set the fill color for \eD objects. 902This is a groff extension and currently ignored. 903.It Ic \&fdeferlig Ar font string ... 904Defer ligature building. 905This is a Heirloom extension and currently ignored. 906.It Ic \&feature Cm + Ns | Ns Cm - Ns Ar name 907Enable or disable an OpenType feature. 908This is a Heirloom extension and currently ignored. 909.It Ic \&fi 910Break the output line and switch to fill mode, 911which is active by default but can be ended with the 912.Ic \&nf 913request. 914In fill mode, input from subsequent input lines is added to 915the same output line until the next word no longer fits, 916at which point the output line is broken. 917This request is implied by the 918.Xr mdoc 7 919.Ic \&Sh 920macro and by the 921.Xr man 7 922.Ic \&SH , 923.Ic \&SS , 924and 925.Ic \&EE 926macros. 927.It Ic \&fkern Ar font minkern 928Control the use of kerning tables for a font. 929This is a Heirloom extension and currently ignored. 930.It Ic \&fl 931Flush output. 932Currently ignored. 933.It Ic \&flig Ar font string char ... 934Define ligatures. 935This is a Heirloom extension and currently ignored. 936.It Ic \&fp Ar position font Op Ar filename 937Assign font position. 938Currently ignored. 939.It Ic \&fps Ar mapname ... 940Mount a font with a special character map. 941This is a Heirloom extension and currently ignored. 942.It Ic \&fschar Ar font glyphname Op Ar string 943Define a font-specific fallback glyph. 944This is a groff extension and currently unsupported. 945.It Ic \&fspacewidth Ar font Op Ar afmunits 946Set a font-specific width for the space character. 947This is a Heirloom extension and currently ignored. 948.It Ic \&fspecial Ar curfont Op Ar font ... 949Conditionally define a special font. 950This is a groff extension and currently ignored. 951.It Ic \&ft Op Ar font 952Change the font; see 953.Sx Font Selection . 954The 955.Ar font 956argument defaults to 957.Cm P . 958.It Ic \&ftr Ar newname Op Ar oldname 959Translate font name. 960This is a groff extension and currently ignored. 961.It Ic \&fzoom Ar font Op Ar permille 962Zoom font size. 963Currently ignored. 964.It Ic \&gcolor Op Ar colorname 965Set glyph color. 966This is a groff extension and currently ignored. 967.It Ic \&hc Op Ar char 968Set the hyphenation character. 969Currently ignored. 970.It Ic \&hcode Ar char code ... 971Set hyphenation codes of characters. 972Currently ignored. 973.It Ic \&hidechar Ar font char ... 974Hide characters in a font. 975This is a Heirloom extension and currently ignored. 976.It Ic \&hla Ar language 977Set hyphenation language. 978This is a groff extension and currently ignored. 979.It Ic \&hlm Op Ar number 980Set maximum number of consecutive hyphenated lines. 981Currently ignored. 982.It Ic \&hpf Ar filename 983Load hyphenation pattern file. 984This is a groff extension and currently ignored. 985.It Ic \&hpfa Ar filename 986Load hyphenation pattern file, appending to the current patterns. 987This is a groff extension and currently ignored. 988.It Ic \&hpfcode Ar code code ... 989Define mapping values for character codes in hyphenation patterns. 990This is a groff extension and currently ignored. 991.It Ic \&hw Ar word ... 992Specify hyphenation points in words. 993Currently ignored. 994.It Ic \&hy Op Ar mode 995Set automatic hyphenation mode. 996Currently ignored. 997.It Ic \&hylang Ar language 998Set hyphenation language. 999This is a Heirloom extension and currently ignored. 1000.It Ic \&hylen Ar nchar 1001Minimum word length for hyphenation. 1002This is a Heirloom extension and currently ignored. 1003.It Ic \&hym Op Ar length 1004Set hyphenation margin. 1005This is a groff extension and currently ignored. 1006.It Ic \&hypp Ar penalty ... 1007Define hyphenation penalties. 1008This is a Heirloom extension and currently ignored. 1009.It Ic \&hys Op Ar length 1010Set hyphenation space. 1011This is a groff extension and currently ignored. 1012.It Ic \&ie Ar condition body 1013The 1014.Dq if 1015half of an if/else conditional. 1016The result of the conditional is pushed into a stack used by subsequent 1017invocations of 1018.Ic \&el , 1019which may be separated by any intervening input (or not exist at all). 1020Its syntax is equivalent to 1021.Ic \&if . 1022.It Ic \&if Ar condition body 1023Begin a conditional. 1024This request can also be written as follows: 1025.Bd -unfilled -offset indent 1026.Pf . Ic \&if Ar condition No \e{ Ns Ar body 1027.Ar body ... Ns \e} 1028.Ed 1029.Bd -unfilled -offset indent 1030.Pf . Ic \&if Ar condition No \e{\e 1031.Ar body ... 1032.Pf . No \e} 1033.Ed 1034.Pp 1035The 1036.Ar condition 1037is a boolean expression. 1038Currently, 1039.Xr mandoc 1 1040supports the following subset of roff conditionals: 1041.Bl -bullet 1042.It 1043If 1044.Sq \&! 1045is prefixed to 1046.Ar condition , 1047it is logically inverted. 1048.It 1049If the first character of 1050.Ar condition 1051is 1052.Sq n 1053.Pq nroff mode 1054or 1055.Sq o 1056.Pq odd page , 1057it evaluates to true, and the 1058.Ar body 1059starts with the next character. 1060.It 1061If the first character of 1062.Ar condition 1063is 1064.Sq e 1065.Pq even page , 1066.Sq t 1067.Pq troff mode , 1068or 1069.Sq v 1070.Pq vroff mode , 1071it evaluates to false, and the 1072.Ar body 1073starts with the next character. 1074.It 1075If the first character of 1076.Ar condition 1077is 1078.Sq c 1079.Pq character available , 1080it evaluates to true if the following character is an ASCII character 1081or a valid character escape sequence, or to false otherwise. 1082The 1083.Ar body 1084starts with the character following that next character. 1085.It 1086If the first character of 1087.Ar condition 1088is 1089.Sq d , 1090it evaluates to true if the rest of 1091.Ar condition 1092is the name of an existing user defined macro or string; 1093otherwise, it evaluates to false. 1094.It 1095If the first character of 1096.Ar condition 1097is 1098.Sq r , 1099it evaluates to true if the rest of 1100.Ar condition 1101is the name of an existing number register; 1102otherwise, it evaluates to false. 1103.It 1104If the 1105.Ar condition 1106starts with a parenthesis or with an optionally signed 1107integer number, it is evaluated according to the rules of 1108.Sx Numerical expressions 1109explained below. 1110It evaluates to true if the result is positive, 1111or to false if the result is zero or negative. 1112.It 1113Otherwise, the first character of 1114.Ar condition 1115is regarded as a delimiter and it evaluates to true if the string 1116extending from its first to its second occurrence is equal to the 1117string extending from its second to its third occurrence. 1118.It 1119If 1120.Ar condition 1121cannot be parsed, it evaluates to false. 1122.El 1123.Pp 1124If a conditional is false, its children are not processed, but are 1125syntactically interpreted to preserve the integrity of the input 1126document. 1127Thus, 1128.Pp 1129.D1 \&.if t .ig 1130.Pp 1131will discard the 1132.Sq \&.ig , 1133which may lead to interesting results, but 1134.Pp 1135.D1 \&.if t .if t \e{\e 1136.Pp 1137will continue to syntactically interpret to the block close of the final 1138conditional. 1139Sub-conditionals, in this case, obviously inherit the truth value of 1140the parent. 1141.Pp 1142If the 1143.Ar body 1144section is begun by an escaped brace 1145.Sq \e{ , 1146scope continues until the end of the input line containing the 1147matching closing-brace escape sequence 1148.Sq \e} . 1149If the 1150.Ar body 1151is not enclosed in braces, scope continues until the end of the line. 1152If the 1153.Ar condition 1154is followed by a 1155.Ar body 1156on the same line, whether after a brace or not, then requests and macros 1157.Em must 1158begin with a control character. 1159It is generally more intuitive, in this case, to write 1160.Bd -unfilled -offset indent 1161.Pf . Ic \&if Ar condition No \e{\e 1162.Pf . Ar request 1163.Pf . No \e} 1164.Ed 1165.Pp 1166than having the request or macro follow as 1167.Pp 1168.D1 Pf . Ic \&if Ar condition Pf \e{. Ar request 1169.Pp 1170The scope of a conditional is always parsed, but only executed if the 1171conditional evaluates to true. 1172.Pp 1173Note that the 1174.Sq \e} 1175is converted into a zero-width escape sequence if not passed as a 1176standalone macro 1177.Sq \&.\e} . 1178For example, 1179.Pp 1180.D1 \&.Fl a \e} b 1181.Pp 1182will result in 1183.Sq \e} 1184being considered an argument of the 1185.Sq \&Fl 1186macro. 1187.It Ic \&ig Op Ar endmacro 1188Ignore input. 1189Its syntax can be either 1190.Bd -literal -offset indent 1191.Pf . Cm \&ig 1192.Ar ignored text 1193\&.. 1194.Ed 1195.Pp 1196or 1197.Bd -literal -offset indent 1198.Pf . Cm \&ig Ar endmacro 1199.Ar ignored text 1200.Pf . Ar endmacro 1201.Ed 1202.Pp 1203In the first case, input is ignored until a 1204.Sq \&.. 1205request is encountered on its own line. 1206In the second case, input is ignored until the specified 1207.Sq Pf . Ar endmacro 1208is encountered. 1209Do not use the escape character 1210.Sq \e 1211anywhere in the definition of 1212.Ar endmacro ; 1213it would cause very strange behaviour. 1214.Pp 1215When the 1216.Ar endmacro 1217is a roff request or a roff macro, like in 1218.Pp 1219.D1 \&.ig if 1220.Pp 1221the subsequent invocation of 1222.Ic \&if 1223will first terminate the 1224.Ar ignored text , 1225then be invoked as usual. 1226Otherwise, it only terminates the 1227.Ar ignored text , 1228and arguments following it or the 1229.Sq \&.. 1230request are discarded. 1231.It Ic \&in Op Oo Cm + Ns | Ns Cm - Oc Ns Ar width 1232Change indentation. 1233See 1234.Xr man 7 . 1235Ignored in 1236.Xr mdoc 7 . 1237.It Ic \&index Ar register stringname substring 1238Find a substring in a string. 1239This is a Heirloom extension and currently unsupported. 1240.It Ic \&it Ar expression macro 1241Set an input line trap. 1242The named 1243.Ar macro 1244will be invoked after processing the number of input text lines 1245specified by the numerical 1246.Ar expression . 1247While evaluating the 1248.Ar expression , 1249the unit suffixes described below 1250.Sx Scaling Widths 1251are ignored. 1252.It Ic \&itc Ar expression macro 1253Set an input line trap, not counting lines ending with \ec. 1254Currently unsupported. 1255.It Ic \&IX Ar class keystring 1256To support the generation of a table of contents, 1257.Xr pod2man 1 1258emits this user-defined macro, usually without defining it. 1259To avoid reporting large numbers of spurious errors, 1260.Xr mandoc 1 1261ignores it. 1262.It Ic \&kern Op Cm 1 | 0 1263Switch kerning on or off. 1264Currently ignored. 1265.It Ic \&kernafter Ar font char ... afmunits ... 1266Increase kerning after some characters. 1267This is a Heirloom extension and currently ignored. 1268.It Ic \&kernbefore Ar font char ... afmunits ... 1269Increase kerning before some characters. 1270This is a Heirloom extension and currently ignored. 1271.It Ic \&kernpair Ar font char ... font char ... afmunits 1272Add a kerning pair to the kerning table. 1273This is a Heirloom extension and currently ignored. 1274.It Ic \&lc Op Ar glyph 1275Define a leader repetition character. 1276Currently unsupported. 1277.It Ic \&lc_ctype Ar localename 1278Set the 1279.Dv LC_CTYPE 1280locale. 1281This is a Heirloom extension and currently unsupported. 1282.It Ic \&lds Ar macroname string 1283Define a local string. 1284This is a Heirloom extension and currently unsupported. 1285.It Ic \&length Ar register string 1286Count the number of input characters in a string. 1287Currently unsupported. 1288.It Ic \&letadj Ar lspmin lshmin letss lspmax lshmax 1289Dynamic letter spacing and reshaping. 1290This is a Heirloom extension and currently ignored. 1291.It Ic \&lf Ar lineno Op Ar filename 1292Change the line number for error messages. 1293Ignored because insecure. 1294.It Ic \&lg Op Cm 1 | 0 1295Switch the ligature mechanism on or off. 1296Currently ignored. 1297.It Ic \&lhang Ar font char ... afmunits 1298Hang characters at left margin. 1299This is a Heirloom extension and currently ignored. 1300.It Ic \&linetabs Op Cm 1 | 0 1301Enable or disable line-tabs mode. 1302This is a groff extension and currently unsupported. 1303.It Ic \&ll Op Oo Cm + Ns | Ns Cm - Oc Ns Ar width 1304Change the output line length. 1305If the 1306.Ar width 1307argument is omitted, the line length is reset to its previous value. 1308The default setting for terminal output is 78n. 1309If a sign is given, the line length is added to or subtracted from; 1310otherwise, it is set to the provided value. 1311Using this request in new manuals is discouraged for several reasons, 1312among others because it overrides the 1313.Xr mandoc 1 1314.Fl O Cm width 1315command line option. 1316.It Ic \&lnr Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar value Op Ar increment 1317Set local number register. 1318This is a Heirloom extension and currently unsupported. 1319.It Ic \&lnrf Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar value Op Ar increment 1320Set local floating-point register. 1321This is a Heirloom extension and currently unsupported. 1322.It Ic \&lpfx Ar string 1323Set a line prefix. 1324This is a Heirloom extension and currently unsupported. 1325.It Ic \&ls Op Ar factor 1326Set line spacing. 1327It takes one integer argument specifying the vertical distance of 1328subsequent output text lines measured in v units. 1329Currently ignored. 1330.It Ic \&lsm Ar macroname 1331Set a leading spaces trap. 1332This is a groff extension and currently unsupported. 1333.It Ic \< Op Oo Cm + Ns | Ns Cm - Oc Ns Ar width 1334Set title line length. 1335Currently ignored. 1336.It Ic \&mc Ar glyph Op Ar dist 1337Print margin character in the right margin. 1338The 1339.Ar dist 1340is currently ignored; instead, 1n is used. 1341.It Ic \&mediasize Ar media 1342Set the device media size. 1343This is a Heirloom extension and currently ignored. 1344.It Ic \&minss Ar width 1345Set minimum word space. 1346This is a Heirloom extension and currently ignored. 1347.It Ic \&mk Op Ar register 1348Mark vertical position. 1349Currently ignored. 1350.It Ic \&mso Ar filename 1351Load a macro file using the search path. 1352Ignored because insecure. 1353.It Ic \&na 1354Disable adjusting without changing the adjustment mode. 1355Currently ignored. 1356.It Ic \&ne Op Ar height 1357Declare the need for the specified minimum vertical space 1358before the next trap or the bottom of the page. 1359Currently ignored. 1360.It Ic \&nf 1361Break the output line and switch to no-fill mode. 1362Subsequent input lines are kept together on the same output line 1363even when exceeding the right margin, 1364and line breaks in subsequent input cause output line breaks. 1365This request is implied by the 1366.Xr mdoc 7 1367.Ic \&Bd Fl unfilled 1368and 1369.Ic \&Bd Fl literal 1370macros and by the 1371.Xr man 7 1372.Ic \&EX 1373macro. 1374The 1375.Ic \&fi 1376request switches back to the default fill mode. 1377.It Ic \&nh 1378Turn off automatic hyphenation mode. 1379Currently ignored. 1380.It Ic \&nhychar Ar char ... 1381Define hyphenation-inhibiting characters. 1382This is a Heirloom extension and currently ignored. 1383.It Ic \&nm Op Ar start Op Ar inc Op Ar space Op Ar indent 1384Print line numbers. 1385Currently unsupported. 1386.It Ic \&nn Op Ar number 1387Temporarily turn off line numbering. 1388Currently unsupported. 1389.It Ic \&nop Ar body 1390Execute the rest of the input line as a request, macro, or text line, 1391skipping the 1392.Ic \&nop 1393request and any space characters immediately following it. 1394This is mostly used to indent text lines inside macro definitions. 1395.It Ic \&nr Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar expression Op Ar stepsize 1396Define or change a register. 1397A register is an arbitrary string value that defines some sort of state, 1398which influences parsing and/or formatting. 1399For the syntax of 1400.Ar expression , 1401see 1402.Sx Numerical expressions 1403below. 1404If it is prefixed by a sign, the register will be 1405incremented or decremented instead of assigned to. 1406.Pp 1407The 1408.Ar stepsize 1409is used by the 1410.Ic \en+ 1411auto-increment feature. 1412It remains unchanged when omitted while changing an existing register, 1413and it defaults to 0 when defining a new register. 1414.Pp 1415The following 1416.Ar register 1417is handled specially: 1418.Bl -tag -width Ds 1419.It Cm nS 1420If set to a positive integer value, certain 1421.Xr mdoc 7 1422macros will behave in the same way as in the 1423.Em SYNOPSIS 1424section. 1425If set to 0, these macros will behave in the same way as outside the 1426.Em SYNOPSIS 1427section, even when called within the 1428.Em SYNOPSIS 1429section itself. 1430Note that starting a new 1431.Xr mdoc 7 1432section with the 1433.Ic \&Sh 1434macro will reset this register. 1435.El 1436.It Xo 1437.Ic \&nrf Ar register Oo Cm + Ns | Ns Cm - Oc Ns Ar expression 1438.Op Ar increment 1439.Xc 1440Define or change a floating-point register. 1441This is a Heirloom extension and currently unsupported. 1442.It Ic \&nroff 1443Force nroff mode. 1444This is a groff extension and currently ignored. 1445.It Ic \&ns 1446Turn on no-space mode. 1447Currently ignored. 1448.It Ic \&nx Op Ar filename 1449Abort processing of the current input file and process another one. 1450Ignored because insecure. 1451.It Ic \&open Ar stream file 1452Open a file for writing. 1453Ignored because insecure. 1454.It Ic \&opena Ar stream file 1455Open a file for appending. 1456Ignored because insecure. 1457.It Ic \&os 1458Output saved vertical space. 1459Currently ignored. 1460.It Ic \&output Ar string 1461Output directly to intermediate output. 1462Not supported. 1463.It Ic \&padj Op Cm 1 | 0 1464Globally control paragraph-at-once adjustment. 1465This is a Heirloom extension and currently ignored. 1466.It Ic \&papersize Ar media 1467Set the paper size. 1468This is a Heirloom extension and currently ignored. 1469.It Ic \&pc Op Ar char 1470Change the page number character. 1471Currently ignored. 1472.It Ic \&pev 1473Print environments. 1474This is a groff extension and currently ignored. 1475.It Ic \&pi Ar command 1476Pipe output to a shell command. 1477Ignored because insecure. 1478.It Ic \&PI 1479Low-level request used by 1480.Ic \&BP . 1481This is a Heirloom extension and currently unsupported. 1482.It Ic \&pl Op Oo Cm + Ns | Ns Cm - Oc Ns Ar height 1483Change page length. 1484Currently ignored. 1485.It Ic \&pm 1486Print names and sizes of macros, strings, and diversions 1487to standard error output. 1488Currently ignored. 1489.It Ic \&pn Oo Cm + Ns | Ns Cm - Oc Ns Ar number 1490Change the page number of the next page. 1491Currently ignored. 1492.It Ic \&pnr 1493Print all number registers on standard error output. 1494Currently ignored. 1495.It Ic \&po Op Oo Cm + Ns | Ns Cm - Oc Ns Ar offset 1496Set a horizontal page offset. 1497If no argument is specified, the page offset is reverted to its 1498previous value. 1499If a sign is specified, the new page offset is calculated relative 1500to the current one; otherwise, it is absolute. 1501The argument follows the syntax of 1502.Sx Scaling Widths 1503and the default scaling unit is 1504.Cm m . 1505.It Ic \&ps Op Oo Cm + Ns | Ns Cm - Oc Ns size 1506Change point size. 1507Currently ignored. 1508.It Ic \&psbb Ar filename 1509Retrieve the bounding box of a PostScript file. 1510Currently unsupported. 1511.It Ic \&pshape Ar indent length ... 1512Set a special shape for the current paragraph. 1513This is a Heirloom extension and currently unsupported. 1514.It Ic \&pso Ar command 1515Include output of a shell command. 1516Ignored because insecure. 1517.It Ic \&ptr 1518Print the names and positions of all traps on standard error output. 1519This is a groff extension and currently ignored. 1520.It Ic \&pvs Op Oo Cm + Ns | Ns Cm - Oc Ns Ar height 1521Change post-vertical spacing. 1522This is a groff extension and currently ignored. 1523.It Ic \&rchar Ar glyph ... 1524Remove glyph definitions. 1525Currently unsupported. 1526.It Ic \&rd Op Ar prompt Op Ar argument ... 1527Read from standard input. 1528Currently ignored. 1529.It Ic \&recursionlimit Ar maxrec maxtail 1530Set the maximum stack depth for recursive macros. 1531This is a Heirloom extension and currently ignored. 1532.It Ic \&return Op Ar twice 1533Exit the presently executed macro and return to the caller. 1534The argument is currently ignored. 1535.It Ic \&rfschar Ar font glyph ... 1536Remove font-specific fallback glyph definitions. 1537Currently unsupported. 1538.It Ic \&rhang Ar font char ... afmunits 1539Hang characters at right margin. 1540This is a Heirloom extension and currently ignored. 1541.It Ic \&rj Op Ar N 1542Justify the next 1543.Ar N 1544input lines to the right margin without filling. 1545.Ar N 1546defaults to 1. 1547An argument of 0 or less ends right adjustment. 1548.It Ic \&rm Ar macroname 1549Remove a request, macro or string. 1550.It Ic \&rn Ar oldname newname 1551Rename a request, macro, diversion, or string. 1552In 1553.Xr mandoc 1 , 1554user-defined macros, 1555.Xr mdoc 7 1556and 1557.Xr man 7 1558macros, and user-defined strings can be renamed, but renaming of 1559predefined strings and of 1560.Nm 1561requests is not supported, and diversions are not implemented at all. 1562.It Ic \&rnn Ar oldname newname 1563Rename a number register. 1564Currently unsupported. 1565.It Ic \&rr Ar register 1566Remove a register. 1567.It Ic \&rs 1568End no-space mode. 1569Currently ignored. 1570.It Ic \&rt Op Ar dist 1571Return to marked vertical position. 1572Currently ignored. 1573.It Ic \&schar Ar glyph Op Ar string 1574Define global fallback glyph. 1575This is a groff extension and currently unsupported. 1576.It Ic \&sentchar Ar char ... 1577Define sentence-ending characters. 1578This is a Heirloom extension and currently ignored. 1579.It Ic \&shc Op Ar glyph 1580Change the soft hyphen character. 1581Currently ignored. 1582.It Ic \&shift Op Ar number 1583Shift macro arguments 1584.Ar number 1585times, by default once: \e\e$i becomes what \e\e$i+number was. 1586Also decrement \en(.$ by 1587.Ar number . 1588.It Ic \&sizes Ar size ... 1589Define permissible point sizes. 1590This is a groff extension and currently ignored. 1591.It Ic \&so Ar filename 1592Include a source file. 1593The file is read and its contents processed as input in place of the 1594.Ic \&so 1595request line. 1596To avoid inadvertent inclusion of unrelated files, 1597.Xr mandoc 1 1598only accepts relative paths not containing the strings 1599.Qq ../ 1600and 1601.Qq /.. . 1602.Pp 1603This request requires 1604.Xr man 1 1605to change to the right directory before calling 1606.Xr mandoc 1 , 1607per convention to the root of the manual tree. 1608Typical usage looks like: 1609.Pp 1610.Dl \&.so man3/Xcursor.3 1611.Pp 1612As the whole concept is rather fragile, the use of 1613.Ic \&so 1614is discouraged. 1615Use 1616.Xr ln 1 1617instead. 1618.It Ic \&sp Op Ar height 1619Break the output line and emit vertical space. 1620The argument follows the syntax of 1621.Sx Scaling Widths 1622and defaults to one blank line 1623.Pq Li 1v . 1624.It Ic \&spacewidth Op Cm 1 | 0 1625Set the space width from the font metrics file. 1626This is a Heirloom extension and currently ignored. 1627.It Ic \&special Op Ar font ... 1628Define a special font. 1629This is a groff extension and currently ignored. 1630.It Ic \&spreadwarn Op Ar width 1631Warn about wide spacing between words. 1632Currently ignored. 1633.It Ic \&ss Ar wordspace Op Ar sentencespace 1634Set space character size. 1635Currently ignored. 1636.It Ic \&sty Ar position style 1637Associate style with a font position. 1638This is a groff extension and currently ignored. 1639.It Ic \&substring Ar stringname startpos Op Ar endpos 1640Replace a user-defined string with a substring. 1641Currently unsupported. 1642.It Ic \&sv Op Ar height 1643Save vertical space. 1644Currently ignored. 1645.It Ic \&sy Ar command 1646Execute shell command. 1647Ignored because insecure. 1648.It Ic \&T& 1649Re-start a table layout, retaining the options of the prior table 1650invocation. 1651See 1652.Ic \&TS . 1653.It Ic \&ta Op Ar width ... Op Cm T Ar width ... 1654Set tab stops. 1655Each 1656.Ar width 1657argument follows the syntax of 1658.Sx Scaling Widths . 1659If prefixed by a plus sign, it is relative to the previous tab stop. 1660The arguments after the 1661.Cm T 1662marker are used repeatedly as often as needed; for each reuse, 1663they are taken relative to the last previously established tab stop. 1664When 1665.Ic \&ta 1666is called without arguments, all tab stops are cleared. 1667.It Ic \&tc Op Ar glyph 1668Change tab repetition character. 1669Currently unsupported. 1670.It Ic \&TE 1671End a table context. 1672See 1673.Ic \&TS . 1674.It Ic \&ti Oo Cm + Ns | Ns Cm - Oc Ns Ar width 1675Break the output line and indent the next output line by 1676.Ar width . 1677If a sign is specified, the temporary indentation is calculated 1678relative to the current indentation; otherwise, it is absolute. 1679The argument follows the syntax of 1680.Sx Scaling Widths 1681and the default scaling unit is 1682.Cm m . 1683.It Ic \&tkf Ar font minps width1 maxps width2 1684Enable track kerning for a font. 1685Currently ignored. 1686.It Ic \&tl No \& Ap Ar left Ap Ar center Ap Ar right Ap 1687Print a title line. 1688Currently unsupported. 1689.It Ic \&tm Ar string 1690Print to standard error output. 1691Currently ignored. 1692.It Ic \&tm1 Ar string 1693Print to standard error output, allowing leading blanks. 1694This is a groff extension and currently ignored. 1695.It Ic \&tmc Ar string 1696Print to standard error output without a trailing newline. 1697This is a groff extension and currently ignored. 1698.It Ic \&tr Ar glyph glyph ... 1699Output character translation. 1700The first glyph in each pair is replaced by the second one. 1701Character escapes can be used; for example, 1702.Pp 1703.Dl tr \e(xx\e(yy 1704.Pp 1705replaces all invocations of \e(xx with \e(yy. 1706.It Ic \&track Ar font minps width1 maxps width2 1707Static letter space tracking. 1708This is a Heirloom extension and currently ignored. 1709.It Ic \&transchar Ar char ... 1710Define transparent characters for sentence-ending. 1711This is a Heirloom extension and currently ignored. 1712.It Ic \&trf Ar filename 1713Output the contents of a file, disallowing invalid characters. 1714This is a groff extension and ignored because insecure. 1715.It Ic \&trimat Ar left top width height 1716Set the TrimBox page parameter for PDF generation. 1717This is a Heirloom extension and currently ignored. 1718.It Ic \&trin Ar glyph glyph ... 1719Output character translation, ignored by 1720.Ic \&asciify . 1721Currently unsupported. 1722.It Ic \&trnt Ar glyph glyph ... 1723Output character translation, ignored by \e!. 1724Currently unsupported. 1725.It Ic \&troff 1726Force troff mode. 1727This is a groff extension and currently ignored. 1728.It Ic \&TS 1729Begin a table, which formats input in aligned rows and columns. 1730See 1731.Xr tbl 7 1732for a description of the tbl language. 1733.It Ic \&uf Ar font 1734Globally set the underline font. 1735Currently ignored. 1736.It Ic \&ul Op Ar N 1737Underline next 1738.Ar N 1739input lines. 1740Currently ignored. 1741.It Ic \&unformat Ar divname 1742Unformat spaces and tabs in a diversion. 1743Currently unsupported. 1744.It Ic \&unwatch Ar macroname 1745Disable notification for string or macro. 1746This is a Heirloom extension and currently ignored. 1747.It Ic \&unwatchn Ar register 1748Disable notification for register. 1749This is a Heirloom extension and currently ignored. 1750.It Ic \&vpt Op Cm 1 | 0 1751Enable or disable vertical position traps. 1752This is a groff extension and currently ignored. 1753.It Ic \&vs Op Oo Cm + Ns | Ns Cm - Oc Ns Ar height 1754Change vertical spacing. 1755Currently ignored. 1756.It Ic \&warn Ar flags 1757Set warning level. 1758Currently ignored. 1759.It Ic \&warnscale Ar si 1760Set the scaling indicator used in warnings. 1761This is a groff extension and currently ignored. 1762.It Ic \&watch Ar macroname 1763Notify on change of string or macro. 1764This is a Heirloom extension and currently ignored. 1765.It Ic \&watchlength Ar maxlength 1766On change, report the contents of macros and strings 1767up to the specified length. 1768This is a Heirloom extension and currently ignored. 1769.It Ic \&watchn Ar register 1770Notify on change of register. 1771This is a Heirloom extension and currently ignored. 1772.It Ic \&wh Ar dist Op Ar macroname 1773Set a page location trap. 1774Currently unsupported. 1775.It Ic \&while Ar condition body 1776Repeated execution while a 1777.Ar condition 1778is true, with syntax similar to 1779.Ic \&if . 1780Currently implemented with two restrictions: cannot nest, 1781and each loop must start and end in the same scope. 1782.It Ic \&write Oo \(dq Oc Ns Ar string 1783Write to an open file. 1784Ignored because insecure. 1785.It Ic \&writec Oo \(dq Oc Ns Ar string 1786Write to an open file without appending a newline. 1787Ignored because insecure. 1788.It Ic \&writem Ar macroname 1789Write macro or string to an open file. 1790Ignored because insecure. 1791.It Ic \&xflag Ar level 1792Set the extension level. 1793This is a Heirloom extension and currently ignored. 1794.El 1795.Ss Numerical expressions 1796The 1797.Ic \&nr , 1798.Ic \&if , 1799and 1800.Ic \&ie 1801requests accept integer numerical expressions as arguments. 1802These are always evaluated using the C 1803.Vt int 1804type; integer overflow works the same way as in the C language. 1805Numbers consist of an arbitrary number of digits 1806.Sq 0 1807to 1808.Sq 9 1809prefixed by an optional sign 1810.Sq + 1811or 1812.Sq - . 1813Each number may be followed by one optional scaling unit described below 1814.Sx Scaling Widths . 1815The following equations hold: 1816.Bd -literal -offset indent 18171i = 6v = 6P = 10m = 10n = 72p = 1000M = 240u = 240 1818254c = 100i = 24000u = 24000 18191f = 65536u = 65536 1820.Ed 1821.Pp 1822The following binary operators are implemented. 1823Unless otherwise stated, they behave as in the C language: 1824.Pp 1825.Bl -tag -width 2n -compact 1826.It Ic + 1827addition 1828.It Ic - 1829subtraction 1830.It Ic * 1831multiplication 1832.It Ic / 1833division 1834.It Ic % 1835remainder of division 1836.It Ic < 1837less than 1838.It Ic > 1839greater than 1840.It Ic == 1841equal to 1842.It Ic = 1843equal to, same effect as 1844.Ic == 1845(this differs from C) 1846.It Ic <= 1847less than or equal to 1848.It Ic >= 1849greater than or equal to 1850.It Ic <> 1851not equal to (corresponds to C 1852.Ic != ; 1853this one is of limited portability, it is supported by Heirloom roff, 1854but not by groff) 1855.It Ic & 1856logical and (corresponds to C 1857.Ic && ) 1858.It Ic \&: 1859logical or (corresponds to C 1860.Ic || ) 1861.It Ic <? 1862minimum (not available in C) 1863.It Ic >? 1864maximum (not available in C) 1865.El 1866.Pp 1867There is no concept of precedence; evaluation proceeds from left to right, 1868except when subexpressions are enclosed in parentheses. 1869Inside parentheses, whitespace is ignored. 1870.Sh ESCAPE SEQUENCE REFERENCE 1871The 1872.Xr mandoc 1 1873.Nm 1874parser recognises the following escape sequences. 1875In 1876.Xr mdoc 7 1877and 1878.Xr man 7 1879documents, using escape sequences is discouraged except for those 1880described in the 1881.Sx LANGUAGE SYNTAX 1882section above. 1883.Pp 1884A backslash followed by any character not listed here 1885simply prints that character itself. 1886.Bl -tag -width Ds 1887.It Ic \e<newline> 1888A backslash at the end of an input line can be used to continue the 1889logical input line on the next physical input line, joining the text 1890on both lines together as if it were on a single input line. 1891.It Ic \e<space> 1892The escape sequence backslash-space 1893.Pq Sq \e\ \& 1894is an unpaddable space-sized non-breaking space character; see 1895.Sx Whitespace 1896and 1897.Xr mandoc_char 7 . 1898.It Ic \e! 1899Embed text up to and including the end of the input line into the 1900current diversion or into intermediate output without interpreting 1901requests, macros, and escapes. 1902Currently unsupported. 1903.It Ic \e\(dq 1904The rest of the input line is treated as 1905.Sx Comments . 1906.It Ic \e# 1907Line continuation with comment. 1908Discard the rest of the physical input line and continue the logical 1909input line on the next physical input line, joining the text on 1910both lines together as if it were on a single input line. 1911This is a groff extension. 1912.It Ic \e$ Ns Ar arg 1913Macro argument expansion, see 1914.Ic \&de . 1915.It Ic \e% 1916Hyphenation allowed at this point of the word; ignored by 1917.Xr mandoc 1 . 1918.It Ic \e& 1919Non-printing zero-width character, 1920often used for various kinds of escaping; see 1921.Sx Whitespace , 1922.Xr mandoc_char 7 , 1923and the 1924.Dq MACRO SYNTAX 1925and 1926.Dq Delimiters 1927sections in 1928.Xr mdoc 7 . 1929.It Ic \e\(aq 1930Acute accent special character; use 1931.Ic \e(aa 1932instead. 1933.It Ic \e( Ns Ar cc 1934.Sx Special Characters 1935with two-letter names, see 1936.Xr mandoc_char 7 . 1937.It Ic \e) 1938Zero-width space transparent to end-of-sentence detection; 1939ignored by 1940.Xr mandoc 1 . 1941.It Ic \e*[ Ns Ar name Ns Ic \&] 1942Interpolate the string with the 1943.Ar name . 1944For short names, there are variants 1945.Ic \e* Ns Ar c 1946and 1947.Ic \e*( Ns Ar cc . 1948.Pp 1949One string is predefined on the 1950.Nm 1951language level: 1952.Ic \e*(.T 1953expands to the name of the output device, 1954for example ascii, utf8, ps, pdf, html, or markdown. 1955.Pp 1956Macro sets traditionally predefine additional strings which are not 1957portable and differ across implementations. 1958Those supported by 1959.Xr mandoc 1 1960are listed in 1961.Xr mandoc_char 7 . 1962.Pp 1963Strings can be defined, changed, and deleted with the 1964.Ic \&ds , 1965.Ic \&as , 1966and 1967.Ic \&rm 1968requests. 1969.It Ic \e, 1970Left italic correction (groff extension); ignored by 1971.Xr mandoc 1 . 1972.It Ic \e- 1973Special character 1974.Dq mathematical minus sign ; 1975see 1976.Xr mandoc_char 7 1977for details. 1978.It Ic \e/ 1979Right italic correction (groff extension); ignored by 1980.Xr mandoc 1 . 1981.It Ic \e: 1982Breaking the line is allowed at this point of the word 1983without inserting a hyphen. 1984.It Ic \e? 1985Embed the text up to the next 1986.Ic \e? 1987into the current diversion without interpreting requests, macros, 1988and escapes. 1989This is a groff extension and currently unsupported. 1990.It Ic \e[ Ns Ar name Ns Ic \&] 1991.Sx Special Characters 1992with names of arbitrary length, see 1993.Xr mandoc_char 7 . 1994.It Ic \e^ 1995One-twelfth em half-narrow space character, effectively zero-width in 1996.Xr mandoc 1 . 1997.It Ic \e_ 1998Underline special character; use 1999.Ic \e(ul 2000instead. 2001.It Ic \e` 2002Grave accent special character; use 2003.Ic \e(ga 2004instead. 2005.It Ic \e{ 2006Begin conditional input; see 2007.Ic \&if . 2008.It Ic \e\(ba 2009One-sixth em narrow space character, effectively zero-width in 2010.Xr mandoc 1 . 2011.It Ic \e} 2012End conditional input; see 2013.Ic \&if . 2014.It Ic \e~ 2015Paddable non-breaking space character. 2016.It Ic \e0 2017Digit width space character. 2018.It Ic \eA\(aq Ns Ar string Ns Ic \(aq 2019Anchor definition; ignored by 2020.Xr mandoc 1 . 2021.It Ic \ea 2022Leader character; ignored by 2023.Xr mandoc 1 . 2024.It Ic \eB\(aq Ns Ar string Ns Ic \(aq 2025Interpolate 2026.Sq 1 2027if 2028.Ar string 2029conforms to the syntax of 2030.Sx Numerical expressions 2031explained above or 2032.Sq 0 2033otherwise. 2034.It Ic \eb\(aq Ns Ar string Ns Ic \(aq 2035Bracket building function; ignored by 2036.Xr mandoc 1 . 2037.It Ic \eC\(aq Ns Ar name Ns Ic \(aq 2038.Sx Special Characters 2039with names of arbitrary length. 2040.It Ic \ec 2041When encountered at the end of an input text line, 2042the next input text line is considered to continue that line, 2043even if there are request or macro lines in between. 2044No whitespace is inserted. 2045.It Ic \eD\(aq Ns Ar string Ns Ic \(aq 2046Draw graphics function; ignored by 2047.Xr mandoc 1 . 2048.It Ic \ed 2049Move down by half a line; ignored by 2050.Xr mandoc 1 . 2051.It Ic \eE 2052Escape character intended to not be interpreted in copy mode. 2053In 2054.Xr mandoc 1 , 2055it currently does the same as 2056.Ic \e 2057itself. 2058.It Ic \ee 2059Backslash special character. 2060.It Ic \eF[ Ns Ar name Ns Ic \&] 2061Switch font family (groff extension); ignored by 2062.Xr mandoc 1 . 2063For short names, there are variants 2064.Ic \eF Ns Ar c 2065and 2066.Ic \eF( Ns Ar cc . 2067.It Ic \ef[ Ns Ar name Ns Ic \&] 2068Switch to the font 2069.Ar name , 2070see 2071.Sx Font Selection . 2072For short names, there are variants 2073.Ic \ef Ns Ar c 2074and 2075.Ic \ef( Ns Ar cc . 2076An empty name 2077.Ic \ef[] 2078defaults to 2079.Ic \efP . 2080.It Ic \eg[ Ns Ar name Ns Ic \&] 2081Interpolate the format of a number register; ignored by 2082.Xr mandoc 1 . 2083For short names, there are variants 2084.Ic \eg Ns Ar c 2085and 2086.Ic \eg( Ns Ar cc . 2087.It Ic \eH\(aq Ns Oo +|- Oc Ns Ar number Ns Ic \(aq 2088Set the height of the current font; ignored by 2089.Xr mandoc 1 . 2090.It Ic \eh\(aq Ns Oo Cm \&| Oc Ns Ar width Ns Ic \(aq 2091Horizontal motion. 2092If the vertical bar is given, the motion is relative to the current 2093indentation. 2094Otherwise, it is relative to the current position. 2095The default scaling unit is 2096.Cm m . 2097.It Ic \ek[ Ns Ar name Ns Ic \&] 2098Mark horizontal input place in register; ignored by 2099.Xr mandoc 1 . 2100For short names, there are variants 2101.Ic \ek Ns Ar c 2102and 2103.Ic \ek( Ns Ar cc . 2104.It Ic \eL\(aq Ns Ar number Ns Oo Ar c Oc Ns Ic \(aq 2105Vertical line drawing function; ignored by 2106.Xr mandoc 1 . 2107.It Ic \el\(aq Ns Ar width Ns Oo Ar c Oc Ns Ic \(aq 2108Draw a horizontal line of 2109.Ar width 2110using the glyph 2111.Ar c . 2112.It Ic \eM[ Ns Ar name Ns Ic \&] 2113Set fill (background) color (groff extension); ignored by 2114.Xr mandoc 1 . 2115For short names, there are variants 2116.Ic \eM Ns Ar c 2117and 2118.Ic \eM( Ns Ar cc . 2119.It Ic \em[ Ns Ar name Ns Ic \&] 2120Set glyph drawing color (groff extension); ignored by 2121.Xr mandoc 1 . 2122For short names, there are variants 2123.Ic \em Ns Ar c 2124and 2125.Ic \em( Ns Ar cc . 2126.It Ic \eN\(aq Ns Ar number Ns Ic \(aq 2127Character 2128.Ar number 2129on the current font. 2130.It Ic \en Ns Oo +|- Oc Ns Ic \&[ Ns Ar name Ns Ic \&] 2131Interpolate the number register 2132.Ar name . 2133For short names, there are variants 2134.Ic \en Ns Ar c 2135and 2136.Ic \en( Ns Ar cc . 2137If the optional sign is specified, 2138the register is first incremented or decremented by the 2139.Ar stepsize 2140that was specified in the relevant 2141.Ic \&nr 2142request, and the changed value is interpolated. 2143.It Ic \eO Ns Ar digit , Ic \eO[5 Ns arguments Ns Ic \&] 2144Suppress output. 2145This is a groff extension and currently unsupported. 2146With an argument of 2147.Ic 1 , 2 , 3 , 2148or 2149.Ic 4 , 2150it is ignored. 2151.It Ic \eo\(aq Ns Ar string Ns Ic \(aq 2152Overstrike, writing all the characters contained in the 2153.Ar string 2154to the same output position. 2155In terminal and HTML output modes, 2156only the last one of the characters is visible. 2157.It Ic \ep 2158Break the output line at the end of the current word. 2159.It Ic \eR\(aq Ns Ar name Oo +|- Oc Ns Ar number Ns Ic \(aq 2160Set number register; ignored by 2161.Xr mandoc 1 . 2162.It Ic \er 2163Move up by one line; ignored by 2164.Xr mandoc 1 . 2165.It Ic \eS\(aq Ns Ar number Ns Ic \(aq 2166Slant output; ignored by 2167.Xr mandoc 1 . 2168.It Ic \es\(aq Ns Oo +|- Oc Ns Ar number Ns Ic \(aq 2169Change point size; ignored by 2170.Xr mandoc 1 . 2171Alternative forms 2172.Ic \es Ns Oo +|- Oc Ns Ar n , 2173.Ic \es Ns Oo +|- Oc Ns Ic \(aq Ns Ar number Ns Ic \(aq , 2174.Ic \es[ Ns Oo +|- Oc Ns Ar number Ns Ic \&] , 2175and 2176.Ic \es Ns Oo +|- Oc Ns Ic \&[ Ns Ar number Ns Ic \&] 2177are also parsed and ignored. 2178.It Ic \et 2179Horizontal tab; ignored by 2180.Xr mandoc 1 . 2181.It Ic \eu 2182Move up by half a line; ignored by 2183.Xr mandoc 1 . 2184.It Ic \eV[ Ns Ar name Ns Ic \&] 2185Interpolate an environment variable; ignored by 2186.Xr mandoc 1 . 2187For short names, there are variants 2188.Ic \eV Ns Ar c 2189and 2190.Ic \eV( Ns Ar cc . 2191.It Ic \ev\(aq Ns Ar number Ns Ic \(aq 2192Vertical motion; ignored by 2193.Xr mandoc 1 . 2194.It Ic \ew\(aq Ns Ar string Ns Ic \(aq 2195Interpolate the width of the 2196.Ar string . 2197The 2198.Xr mandoc 1 2199implementation assumes that after expansion of user-defined strings, the 2200.Ar string 2201only contains normal characters, no escape sequences, and that each 2202character has a width of 24 basic units. 2203.It Ic \eX\(aq Ns Ar string Ns Ic \(aq 2204Output 2205.Ar string 2206as device control function; ignored in nroff mode and by 2207.Xr mandoc 1 . 2208.It Ic \ex\(aq Ns Ar number Ns Ic \(aq 2209Extra line space function; ignored by 2210.Xr mandoc 1 . 2211.It Ic \eY[ Ns Ar name Ns Ic \&] 2212Output a string as a device control function; ignored in nroff mode and by 2213.Xr mandoc 1 . 2214For short names, there are variants 2215.Ic \eY Ns Ar c 2216and 2217.Ic \eY( Ns Ar cc . 2218.It Ic \eZ\(aq Ns Ar string Ns Ic \(aq 2219Print 2220.Ar string 2221with zero width and height; ignored by 2222.Xr mandoc 1 . 2223.It Ic \ez 2224Output the next character without advancing the cursor position. 2225.El 2226.Sh COMPATIBILITY 2227The 2228.Xr mandoc 1 2229implementation of the 2230.Nm 2231language is incomplete. 2232Major unimplemented features include: 2233.Pp 2234.Bl -dash -compact 2235.It 2236For security reasons, 2237.Xr mandoc 1 2238never reads or writes external files except via 2239.Ic \&so 2240requests with safe relative paths. 2241.It 2242There is no automatic hyphenation, no adjustment to the right margin, 2243and very limited support for centering; the output is always set flush-left. 2244.It 2245Support for setting tabulator and leader characters is missing, 2246and support for manually changing indentation is limited. 2247.It 2248The 2249.Sq u 2250scaling unit is the default terminal unit. 2251In traditional troff systems, this unit changes depending on the 2252output media. 2253.It 2254Width measurements are implemented in a crude way 2255and often yield wrong results. 2256Support for explicit movement requests and escapes is limited. 2257.It 2258There is no concept of output pages, no support for floats, 2259graphics drawing, and picture inclusion; 2260terminal output is always continuous. 2261.It 2262Requests regarding color, font families, font sizes, 2263and glyph manipulation are ignored. 2264Font support is very limited. 2265Kerning is not implemented, and no ligatures are produced. 2266.It 2267The 2268.Qq \(aq 2269macro control character does not suppress output line breaks. 2270.It 2271Diversions and environments are not implemented, 2272and support for traps is very incomplete. 2273.It 2274Use of macros is not supported inside 2275.Xr tbl 7 2276code. 2277.El 2278.Pp 2279The special semantics of the 2280.Cm nS 2281number register is an idiosyncracy of 2282.Ox 2283manuals and not supported by other 2284.Xr mdoc 7 2285implementations. 2286.Sh SEE ALSO 2287.Xr mandoc 1 , 2288.Xr eqn 7 , 2289.Xr man 7 , 2290.Xr mandoc_char 7 , 2291.Xr mdoc 7 , 2292.Xr tbl 7 2293.Rs 2294.%A Joseph F. Ossanna 2295.%A Brian W. Kernighan 2296.%I AT&T Bell Laboratories 2297.%T Troff User's Manual 2298.%R Computing Science Technical Report 2299.%N 54 2300.%C Murray Hill, New Jersey 2301.%D 1976 and 1992 2302.%U http://www.kohala.com/start/troff/cstr54.ps 2303.Re 2304.Rs 2305.%A Joseph F. Ossanna 2306.%A Brian W. Kernighan 2307.%A Gunnar Ritter 2308.%T Heirloom Documentation Tools Nroff/Troff User's Manual 2309.%D September 17, 2007 2310.%U http://heirloom.sourceforge.net/doctools/troff.pdf 2311.Re 2312.Sh HISTORY 2313The RUNOFF typesetting system, whose input forms the basis for 2314.Nm , 2315was written in MAD and FAP for the CTSS operating system by Jerome E. 2316Saltzer in 1964. 2317Doug McIlroy rewrote it in BCPL in 1969, renaming it 2318.Nm . 2319Dennis M. Ritchie rewrote McIlroy's 2320.Nm 2321in PDP-11 assembly for 2322.At v1 , 2323Joseph F. Ossanna improved roff and renamed it nroff 2324for 2325.At v2 , 2326then ported nroff to C as troff, which Brian W. Kernighan released with 2327.At v7 . 2328In 1989, James Clarke re-implemented troff in C++, naming it groff. 2329.Sh AUTHORS 2330.An -nosplit 2331This 2332.Nm 2333reference was written by 2334.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv 2335and 2336.An Ingo Schwarze Aq Mt schwarze@openbsd.org . 2337