1 .\" $Id: mandoc.1,v 1.128 2014/12/02 11:31:51 schwarze Exp $
3 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4 .\" Copyright (c) 2012, 2014 Ingo Schwarze <schwarze@openbsd.org>
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.
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.
18 .Dd $Mdocdate: December 2 2014 $
23 .Nd format and display UNIX manuals
28 .Op Fl I Cm os Li = Ar name
30 .Op Fl K Ns Ar encoding
41 manual pages for display.
49 text from stdin, implying
55 The options are as follows:
58 If the standard output is a terminal device and
62 to paginate the output, just like
66 Copy the formatted manual pages to the standard output without using
70 It can be specified to override
75 This overrides any earlier
81 .It Fl I Cm os Li = Ar name
83 Override the default operating system
90 Display only the SYNOPSIS lines.
93 .It Fl K Ns Ar encoding
94 Specify the input encoding.
102 If not specified, autodetection uses the first match:
103 .Bl -tag -width iso-8859-1
105 if the first three bytes of the input file
106 are the UTF-8 byte order mark (BOM, 0xefbbbf)
108 if the first or second line of the input file matches the
112 .D1 .\e" -*- Oo ...; Oc coding: Ar encoding ; No -*-
114 if the first non-ASCII byte in the file introduces a valid UTF-8 sequence
121 This overrides any earlier
129 Also reverts any earlier
134 .It Fl m Ns Ar format
138 for available formats.
141 .It Fl O Ns Ar option
142 Comma-separated output options.
143 .It Fl T Ns Ar output
147 for available formats.
151 Print version and exit.
153 Specify the minimum message
155 to be reported on the standard error output and to affect the exit status.
167 .Fl W Ns Cm warning .
178 to exit after parsing a file that causes warnings or errors of at least
180 No formatted output will be produced from that file.
185 are requested, they can be joined with a comma, for example
186 .Fl W Ns Cm error , Ns Cm stop .
188 Read input from zero or more files.
189 If unspecified, reads from stdin.
190 If multiple files are specified,
192 will halt with the first failed parse.
201 also supports the options
224 should only be used for legacy manuals.
228 which is also the default, determines encoding on-the-fly: if the first
235 parser is used; otherwise, the
240 files are specified with
242 each has its file-type determined this way.
243 If multiple files are
248 is specified, then this format is used exclusively.
252 utility accepts the following
254 arguments, which correspond to output modes:
255 .Bl -tag -width "-Tlocale"
257 Produce 7-bit ASCII output.
261 Produce HTML5, CSS1, and MathML output.
265 Parse only: produce no output.
267 .Fl W Ns Cm warning .
268 .It Fl T Ns Cm locale
269 Encode output using the current locale.
284 Produce PostScript output.
286 .Sx PostScript Output .
288 Produce an indented parse tree.
290 Encode output in the UTF\-8 multi-byte format.
294 This is a synonym for
298 If multiple input files are specified, these will be processed by the
299 corresponding filter in-order.
303 is rendered in standard 7-bit ASCII documented in
306 Font styles are applied by using back-spaced encoding such that an
310 .Sq _ Ns \e[bs] Ns c ,
313 is the back-space character number 8.
314 Emboldened characters are rendered as
315 .Sq c Ns \e[bs] Ns c .
317 The special characters documented in
319 are rendered best-effort in an ASCII equivalent.
320 If no equivalent is found,
324 Output width is limited to 78 visible columns unless literal input lines
329 arguments are accepted:
331 .It Cm indent Ns = Ns Ar indent
332 The left margin for normal text is set to
334 blank characters instead of the default of five for
338 Increasing this is not recommended; it may result in degraded formatting,
339 for example overfull lines or ugly line breaks.
340 .It Cm width Ns = Ns Ar width
341 The output width is set to
343 which will normalise to \(>=60.
348 conforms to HTML5 using optional self-closing tags.
349 Default styles use only CSS1.
350 Equations rendered from
355 .Pa example.style.css
356 file documents style-sheet classes available for customising output.
357 If a style-sheet is not specified with
360 defaults to simple output (via an embedded style-sheet)
361 readable in any graphical or text-based web
364 Special characters are rendered in decimal-encoded UTF\-8.
368 arguments are accepted:
371 Omit the <!DOCTYPE> declaration and the <html>, <head>, and <body>
372 elements and only emit the subtree below the <body> element.
375 argument will be ignored.
376 This is useful when embedding manual content within existing documents.
377 .It Cm includes Ns = Ns Ar fmt
382 is used as a template for linked header files (usually via the
387 are replaced with the include filename.
388 The default is not to present a
390 .It Cm man Ns = Ns Ar fmt
394 .Ar ../html%S/%N.%S.html ,
395 is used as a template for linked manuals (usually via the
402 are replaced with the linked manual's name and section, respectively.
403 If no section is included, section 1 is assumed.
404 The default is not to
406 .It Cm style Ns = Ns Ar style.css
409 is used for an external style-sheet.
410 This must be a valid absolute or
414 Locale-depending output encoding is triggered with
418 This option is not available on all systems: systems without locale
419 support, or those whose internal representation is not natively UCS-4,
424 for font style specification and available command-line arguments.
426 Translate input format into
429 This is useful for distributing manual sources to legacy systems
436 is passed as input, it is translated into
438 If the input format is
440 the input is copied to the output, expanding any
444 The parser is also run, and as usual, the
448 are displayed before copying the input to the output.
450 PDF-1.1 output may be generated by
453 .Sx PostScript Output
456 arguments and defaults.
457 .Ss PostScript Output
460 Level-2 pages may be generated by
462 Output pages default to letter sized and are rendered in the Times font
464 Margins are calculated as 1/9 the page length and width.
467 Special characters are rendered as in
472 arguments are accepted:
474 .It Cm paper Ns = Ns Ar name
484 You may also manually specify dimensions as
486 width by height in millimetres.
487 If an unknown value is encountered,
494 to force a UTF\-8 locale.
497 for details and options.
499 .Bl -tag -width MANPAGER
501 Any non-empty value of the environment variable
503 will be used instead of the standard pagination program,
506 Specifies the pagination program to use when
509 If neither PAGER nor MANPAGER is defined,
510 .Pa /usr/bin/more Fl s
516 utility exits with one of the following values, controlled by the message
522 .Bl -tag -width Ds -compact
524 No warnings or errors occurred, or those that did were ignored because
525 they were lower than the requested
528 At least one warning occurred, but no error, and
532 At least one parsing error occurred, but no fatal error, and
538 A fatal parsing error occurred.
540 Invalid command line arguments were specified.
541 No input files have been read.
543 An operating system error occurred, for example memory exhaustion or an
544 error accessing input files.
547 to exit at once, possibly in the middle of parsing or formatting a file.
553 .Fl W Ns Cm warning .
555 To page manuals to the terminal:
557 .Dl $ mandoc \-Wall,stop mandoc.1 2\*(Gt&1 | less
558 .Dl $ mandoc mandoc.1 mdoc.3 mdoc.7 | less
560 To produce HTML manuals with
564 .Dl $ mandoc \-Thtml -Ostyle=style.css mdoc.7 \*(Gt mdoc.7.html
566 To check over a large set of manuals:
568 .Dl $ mandoc \-Tlint `find /usr/src -name \e*\e.[1-9]`
570 To produce a series of PostScript manuals for A4 paper:
572 .Dl $ mandoc \-Tps \-Opaper=a4 mdoc.7 man.7 \*(Gt manuals.ps
578 format, for use on systems lacking an
582 .Dl $ mandoc \-Tman foo.mdoc \*(Gt foo.man
584 Messages displayed by
588 .D1 Nm Ns : Ar file : Ns Ar line : Ns Ar column : level : message : macro args
590 Line and column numbers start at 1.
591 Both are omitted for messages referring to an input file as a whole.
592 Macro names and arguments are omitted where meaningless.
593 Fatal messages about invalid command line arguments
594 or operating system errors, for example when memory is exhausted,
601 Message levels have the following meanings:
602 .Bl -tag -width "warning"
604 Opening or reading an input file failed, so the parser cannot
605 even be started and no output is produced from that input file.
607 The parser is unable to parse a given input file at all.
608 No formatted output is produced from that input file.
610 An input file contains syntax that cannot be safely interpreted,
611 either because it is invalid or because
613 does not implement it yet.
614 By discarding part of the input or inserting missing tokens,
615 the parser is able to continue, and the error does not prevent
616 generation of formatted output, but typically, preparing that
617 output involves information loss, broken document structure
618 or unintended formatting.
620 An input file uses obsolete, discouraged or non-portable syntax.
621 All the same, the meaning of the input is unambiguous and a correct
622 rendering can be produced.
623 Documents causing warnings may render poorly when using other
624 formatting tools instead of
632 levels are hidden unless their level, or a lower level, is requested using a
637 .Ss Warnings related to the document prologue
639 .It Sy "missing manual title, using UNTITLED"
643 macro has no arguments, or there is no
645 macro before the first non-prologue macro.
646 .It Sy "missing manual title, using \(dq\(dq"
650 macro, or it has no arguments.
651 .It Sy "lower case character in document title"
653 The title is still used as given in the
658 .It Sy "missing manual section, using \(dq\(dq"
664 macro lacks the mandatory section argument.
665 .It Sy "unknown manual section"
667 The section number in a
669 line is invalid, but still used.
670 .It Sy "missing date, using today's date"
672 The document was parsed as
678 macro has no arguments or only empty arguments;
679 or the document was parsed as
685 macro has less than three arguments or its third argument is empty.
686 .It Sy "cannot parse date, using it verbatim"
692 macro does not follow the conventional format.
693 .It Sy "missing Os macro, using \(dq\(dq"
695 The default or current system is not shown in this case.
696 .It Sy "duplicate prologue macro"
698 One of the prologue macros occurs more than once.
699 The last instance overrides all previous ones.
700 .It Sy "late prologue macro"
706 macro occurs after some non-prologue macro, but still takes effect.
707 .It Sy "skipping late title macro"
711 macro can only occur before the first non-prologue macro
712 because traditional formatters write the page header
713 before parsing the document body.
714 Even though this technical restriction does not apply to
716 traditional semantics is preserved.
717 The late macro is discarded including its arguments.
718 .It Sy "prologue macros out of order"
720 The prologue macros are not given in the conventional order
724 All three macros are used even when given in another order.
726 .Ss Warnings regarding document structure
728 .It Sy ".so is fragile, better use ln(1)"
730 Including files only works when the parser program runs with the correct
731 current working directory.
732 .It Sy "no document body"
734 The document body contains neither text nor macros.
735 An empty document is shown, consisting only of a header and a footer line.
736 .It Sy "content before first section header"
738 Some macros or text precede the first
743 The offending macros and text are parsed and added to the top level
744 of the syntax tree, outside any section block.
745 .It Sy "first section is not NAME"
747 The argument of the first
755 .It Sy "bad NAME section contents"
757 The last node in the NAME section is not an
759 macro, or any preceding macro is not
761 or the NAME section is completely empty.
766 .It Sy "sections out of conventional order"
768 A standard section occurs after another section it usually precedes.
769 All section titles are used as given,
770 and the order of sections is not changed.
771 .It Sy "duplicate section title"
773 The same standard section title occurs more than once.
774 .It Sy "unexpected section"
776 A standard section header occurs in a section of the manual
777 where it normally isn't useful.
778 .It Sy "unusual Xr order"
780 In the SEE ALSO section, an
782 macro with a lower section number follows one with a higher number,
785 macros refering to the same section are out of alphabetical order.
786 .It Sy "unusual Xr punctuation"
788 In the SEE ALSO section, punctuation between two
790 macros differs from a single comma, or there is trailing punctuation
794 .It Sy "AUTHORS section without An macro"
796 An AUTHORS sections contains no
798 macros, or only empty ones.
799 Probably, there are author names lacking markup.
801 .Ss "Warnings related to macros and nesting"
803 .It Sy "obsolete macro"
807 manual for replacements.
808 .It Sy "macro neither callable nor escaped"
810 The name of a macro that is not callable appears on a macro line.
811 It is printed verbatim.
812 If the intention is to call it, move it to its own line;
813 otherwise, escape it by prepending
815 .It Sy "skipping paragraph macro"
818 documents, this happens
821 at the beginning and end of sections and subsections
823 right before non-compact lists and displays
825 at the end of items in non-column, non-compact lists
827 and for multiple consecutive paragraph macros.
831 documents, it happens
843 macros having neither head nor body arguments
854 .It Sy "moving paragraph macro out of list"
858 list contains a trailing paragraph macro.
859 The paragraph macro is moved after the end of the list.
860 .It Sy "skipping no-space macro"
862 An input line begins with an
865 The macro is ignored.
866 .It Sy "blocks badly nested"
868 If two blocks intersect, one should completely contain the other.
869 Otherwise, rendered output is likely to look strange in any output
870 format, and rendering in SGML-based output formats is likely to be
871 outright wrong because such languages do not support badly nested
873 Typical examples of badly nested blocks are
874 .Qq Ic \&Ao \&Bo \&Ac \&Bc
876 .Qq Ic \&Ao \&Bq \&Ac .
884 .It Sy "nested displays are not portable"
891 display occurs nested inside another
896 but fails with most other implementations.
897 .It Sy "moving content out of list"
901 list block contains text or macros before the first
904 The offending children are moved before the beginning of the list.
905 .It Sy ".Vt block has child macro"
909 macro supports plain text arguments only.
910 Formatting may be ugly and semantic searching
911 for the affected content might not work.
912 .It Sy "fill mode already enabled, skipping"
916 request occurs even though the document is still in fill mode,
917 or already switched back to fill mode.
919 .It Sy "fill mode already disabled, skipping"
923 request occurs even though the document already switched to no-fill mode
924 and did not switch back to fill mode yet.
926 .It Sy "line scope broken"
928 While parsing the next-line scope of the previous macro,
929 another macro is found that prematurely terminates the previous one.
930 The previous, interrupted macro is deleted from the parse tree.
932 .Ss "Warnings related to missing arguments"
934 .It Sy "skipping empty request"
936 The macro name is missing from a macro definition request,
939 control statement or operation keyword lacks its required argument.
940 .It Sy "conditional request controls empty scope"
942 A conditional request is only useful if any of the following
943 follows it on the same logical input line:
948 keyword to open a multi-line scope.
950 A request or macro or some text, resulting in a single-line scope.
952 The immediate end of the logical line without any intervening whitespace,
953 resulting in next-line scope.
955 Here, a conditional request is followed by trailing whitespace only,
956 and there is no other content on its logical input line.
957 Note that it doesn't matter whether the logical input line is split
958 across multiple physical input lines using
960 line continuation characters.
961 This is one of the rare cases
962 where trailing whitespace is syntactically significant.
963 The conditional request controls a scope containing whitespace only,
964 so it is unlikely to have a significant effect,
965 except that it may control a following
968 .It Sy "skipping empty macro"
970 The indicated macro has no arguments and hence no effect.
971 .It Sy "empty argument, using 0n"
973 The required width is missing after
980 .It Sy "argument count wrong"
982 The indicated macro has too few or too many arguments.
983 The syntax tree will contain the wrong number of arguments as given.
984 Formatting behaviour depends on the specific macro in question.
985 Note that the same message may also occur as an ERROR, see below.
986 .It Sy "missing display type, using -ragged"
990 macro is invoked without the required display type.
991 .It Sy "list type is not the first argument"
995 macro, at least one other argument precedes the type argument.
998 utility copes with any argument order, but some other
1000 implementations do not.
1001 .It Sy "missing -width in -tag list, using 8n"
1010 .It Sy "missing utility name, using \(dq\(dq"
1014 macro is called without an argument before
1016 has first been called with an argument.
1017 .It Sy "empty head in list item"
1029 macro lacks the required argument.
1030 The item head is left empty.
1031 .It Sy "empty list item"
1043 An empty list item is shown.
1044 .It Sy "missing font type"
1048 macro has no argument.
1049 It switches to the default font,
1051 .It Sy "unknown font type"
1055 argument is invalid.
1059 .It Sy "nothing follows prefix"
1063 macro has no argument, or only one argument and no macro follows
1064 on the same input line.
1065 This defeats its purpose; in particular, spacing is not suppressed
1066 before the text or macros following on the next input line.
1067 .It Sy "missing -std argument, adding it"
1073 macro lacks the required
1080 even when it is not specified, but other implementations may not.
1081 .It Sy "missing eqn box, using \(dq\(dq"
1083 A diacritic mark or a binary operator is found,
1084 but there is nothing to the left of it.
1085 An empty box is inserted.
1087 .Ss "Warnings related to bad macro arguments"
1089 .It Sy "unterminated quoted argument"
1091 Macro arguments can be enclosed in double quote characters
1092 such that space characters and macro names contained in the quoted
1093 argument need not be escaped.
1094 The closing quote of the last argument of a macro can be omitted.
1095 However, omitting it is not recommended because it makes the code
1097 .It Sy "duplicate argument"
1103 macro has more than one
1110 All but the last instances of these arguments are ignored.
1111 .It Sy "skipping duplicate argument"
1115 macro has more than one
1120 All but the first of these arguments are ignored.
1121 .It Sy "skipping duplicate display type"
1125 macro has more than one type argument; the first one is used.
1126 .It Sy "skipping duplicate list type"
1130 macro has more than one type argument; the first one is used.
1131 .It Sy "skipping -width argument"
1145 .It Sy "unknown AT&T UNIX version"
1149 macro has an invalid argument.
1150 It is used verbatim, with
1153 .It Sy "comma in function argument"
1159 macro contains a comma; it should probably be split into two arguments.
1160 .It Sy "parenthesis in function name"
1162 The first argument of an
1166 macro contains an opening or closing parenthesis; that's probably wrong,
1167 parentheses are added automatically.
1168 .It Sy "invalid content in Rs block"
1172 block contains plain text or non-% macros.
1173 The bogus content is left in the syntax tree.
1174 Formatting may be poor.
1175 .It Sy "invalid Boolean argument"
1179 macro has an argument other than
1183 The invalid argument is moved out of the macro, which leaves the macro
1184 empty, causing it to toggle the spacing mode.
1185 .It Sy "unknown font, skipping request"
1193 layout modifier has an unknown
1197 .Ss "Warnings related to plain text"
1199 .It Sy "blank line in fill mode, using .sp"
1201 The meaning of blank input lines is only well-defined in non-fill mode:
1202 In fill mode, line breaks of text input lines are not supposed to be
1204 However, for compatibility with groff, blank lines in fill mode
1208 .It Sy "tab in filled text"
1210 The meaning of tab characters is only well-defined in non-fill mode:
1211 In fill mode, whitespace is not supposed to be significant
1212 on text input lines.
1213 As an implementation dependent choice, tab characters on text lines
1214 are passed through to the formatters in any case.
1215 Given that the text before the tab character will be filled,
1216 it is hard to predict which tab stop position the tab will advance to.
1217 .It Sy "whitespace at end of input line"
1218 .Pq mdoc , man , roff
1219 Whitespace at the end of input lines is almost never semantically
1220 significant \(em but in the odd case where it might be, it is
1221 extremely confusing when reviewing and maintaining documents.
1222 .It Sy "bad comment style"
1224 Comment lines start with a dot, a backslash, and a double-quote character.
1227 utility treats the line as a comment line even without the backslash,
1228 but leaving out the backslash might not be portable.
1229 .It Sy "invalid escape sequence"
1231 An escape sequence has an invalid opening argument delimiter, lacks the
1232 closing argument delimiter, or the argument has too few characters.
1233 If the argument is incomplete,
1237 expand to an empty string,
1243 to the length of the incomplete argument.
1244 All other invalid escape sequences are ignored.
1245 .It Sy "undefined string, using \(dq\(dq"
1247 If a string is used without being defined before,
1248 its value is implicitly set to the empty string.
1249 However, defining strings explicitly before use
1250 keeps the code more readable.
1252 .Ss "Errors related to equations"
1254 .It "unexpected equation scope closure"
1255 .It "equation scope open on exit"
1256 .It "overlapping equation scopes"
1257 .It "unexpected end of equation"
1259 .Ss "Errors related to tables"
1261 .It "bad table syntax"
1262 .It "bad table option"
1263 .It "bad table layout"
1264 .It "no table layout cells specified"
1265 .It "no table data cells specified"
1266 .It "ignore data in cell"
1267 .It "data block still open"
1268 .It "ignoring extra data cells"
1270 .Ss "Errors related to roff, mdoc, and man code"
1272 .It Sy "input stack limit exceeded, infinite loop?"
1274 Explicit recursion limits are implemented for the following features,
1275 in order to prevent infinite loops:
1278 expansion of nested escape sequences
1279 including expansion of strings and number registers,
1281 expansion of nested user-defined macros,
1287 When a limit is hit, the output is incorrect, typically losing
1288 some content, but the parser can continue.
1289 .It Sy "skipping bad character"
1290 .Pq mdoc , man , roff
1291 The input file contains a byte that is not a printable
1294 The message mentions the character number.
1295 The offending byte is replaced with a question mark
1297 Consider editing the input file to replace the byte with an ASCII
1298 transliteration of the intended character.
1299 .It Sy "skipping unknown macro"
1300 .Pq mdoc , man , roff
1301 The first identifier on a request or macro line is neither recognized as a
1303 request, nor as a user-defined macro, nor, respectively, as an
1308 It may be mistyped or unsupported.
1309 The request or macro is discarded including its arguments.
1310 .It Sy "skipping item outside list"
1314 macro occurs outside any
1319 delimiter occurs outside any pile.
1320 It is discarded including its arguments.
1321 .It Sy "skipping column outside column list"
1325 macro occurs outside any
1328 It is discarded including its arguments.
1329 .It Sy "skipping end of block that is not open"
1330 .Pq mdoc , man , eqn , tbl , roff
1331 Various syntax elements can only be used to explicitly close blocks
1332 that have previously been opened.
1335 block closing macro, a
1342 right delimiter or closing brace, or the end of an equation, table, or
1344 conditional request is encountered but no matching block is open.
1345 The offending request or macro is discarded.
1346 .It Sy "inserting missing end of block"
1350 macros as well as tables require explicit closing by dedicated macros.
1351 A block that doesn't support bad nesting
1352 ends before all of its children are properly closed.
1353 The open child nodes are closed implicitly.
1354 .It Sy "scope open on exit"
1355 .Pq mdoc , man , eqn , tbl , roff
1356 At the end of the document, an explicit
1364 block, an equation, table, or
1366 conditional or ignore block is still open.
1367 The open block is closed implicitly.
1368 .It Sy "escaped character not allowed in a name"
1370 Macro, string and register identifiers consist of printable,
1371 non-whitespace ASCII characters.
1372 Escape sequences and characters and strings expressed in terms of them
1373 cannot form part of a name.
1374 The first argument of an
1382 request, or any argument of an
1384 request, or the name of a request or user defined macro being called,
1385 is terminated by an escape sequence.
1391 the request has no effect at all.
1398 what was parsed up to this point is used as the arguments to the request,
1399 and the rest of the input line is discarded including the escape sequence.
1400 When parsing for a request or a user-defined macro name to be called,
1401 only the escape sequence is discarded.
1402 The characters preceding it are used as the request or macro name,
1403 the characters following it are used as the arguments to the request or macro.
1404 .It Sy "argument count wrong"
1405 .Pq mdoc , man , roff
1406 The indicated request or macro has too few or too many arguments.
1407 The syntax tree will contain the wrong number of arguments as given.
1408 Formatting behaviour depends on the specific request or macro in question.
1409 Note that the same message may also occur as a WARNING, see above.
1410 .It Sy "NOT IMPLEMENTED: Bd -file"
1412 For security reasons, the
1414 macro does not support the
1417 By requesting the inclusion of a sensitive file, a malicious document
1418 might otherwise trick a privileged user into inadvertently displaying
1419 the file on the screen, revealing the file content to bystanders.
1420 The argument is ignored including the file name following it.
1421 .It Sy "missing list type, using -item"
1425 macro fails to specify the list type.
1426 .It Sy "missing manual name, using \(dq\(dq"
1430 lacks the required argument.
1431 .It Sy "uname(3) system call failed, using UNKNOWN"
1435 macro is called without arguments, and the
1440 can be compiled with
1442 .Fl D Cm OSNAME=\(dq\e\(dq Ar string Cm \e\(dq\(dq .
1444 .It Sy "unknown standard specifier"
1448 macro has an unknown argument and is discarded.
1449 .It Sy "skipping request without numeric argument"
1458 statement has a non-numeric or negative argument or no argument at all.
1459 The invalid request or statement is ignored.
1460 .It Sy "skipping all arguments"
1461 .Pq mdoc , man , eqn , roff
1474 macro in a list that don't support item heads, a
1488 block closing request is invoked with at least one argument.
1489 All arguments are ignored.
1490 .It Sy "skipping excess arguments"
1494 macro is invoked with more than one argument, or a request of the
1496 family is invoked with more than two arguments.
1497 The excess arguments are ignored.
1501 .It Sy "input too large"
1505 cannot handle input files larger than its arbitrary size limit
1506 of 2^31 bytes (2 Gigabytes).
1507 Since useful manuals are always small, this is not a problem in practice.
1508 Parsing is aborted as soon as the condition is detected.
1509 .It Sy "NOT IMPLEMENTED: .so with absolute path or \(dq..\(dq"
1511 For security reasons,
1515 file inclusion requests only with relative paths
1516 and only without ascending to any parent directory.
1517 By requesting the inclusion of a sensitive file, a malicious document
1518 might otherwise trick a privileged user into inadvertently displaying
1519 the file on the screen, revealing the file content to bystanders.
1520 The parser exits immediately.
1521 .It Sy ".so request failed"
1525 request requires reading an external file.
1526 While trying to do so, an
1532 The parser exits immediately.
1533 Before showing this message,
1535 always shows another message explaining why the system call failed.
1538 This section summarises
1540 compatibility with GNU troff.
1541 Each input and output format is separately noted.
1542 .Ss ASCII Compatibility
1543 .Bl -bullet -compact
1545 Unrenderable unicode codepoints specified with
1547 escapes are printed as
1550 In GNU troff, these raise an error.
1560 are synonyms, as are \-filled and \-ragged.
1562 In historic GNU troff, the
1565 macro does not underline when scoped under an
1567 in the FILES section.
1568 This behaves correctly in
1571 A list or display following the
1576 does not assert a prior vertical break, just as it doesn't with
1586 Words aren't hyphenated.
1588 .Ss HTML Compatibility
1589 .Bl -bullet -compact
1593 escape will revert the font to the previous
1595 escape, not to the last rendered decoration, which is now dictated by
1596 CSS instead of hard-coded.
1597 It also will not span past the current scope,
1598 for the same reason.
1601 mode, this will work fine.
1608 list types render similarly (no break following overreached left-hand
1609 side) due to the expressive constraints of HTML.
1616 lists render similarly.
1628 utility was written by
1629 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
1635 the maximum size of an element attribute is determined by
1637 which is usually 1024 bytes.
1638 Be aware of this when setting long link
1640 .Fl O Ns Cm style Ns = Ns Ar really/long/link .
1642 Nesting elements within next-line element scopes of
1652 and cause them to forget the formatting of the prior next-line scope.
1656 control character is an alias for the standard macro control character
1657 and does not emit a line-break as stipulated in GNU troff.
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