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Diff for /mandoc/mandoc.1 between version 1.87 and 1.155

version 1.87, 2011/05/17 22:32:45 version 1.155, 2015/02/23 13:31:03
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 .\"     $Id$  .\"     $Id$
 .\"  .\"
 .\" Copyright (c) 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>  .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
   .\" Copyright (c) 2012, 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
 .\"  .\"
 .\" Permission to use, copy, modify, and distribute this software for any  .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above  .\" purpose with or without fee is hereby granted, provided that the above
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 .Nd format and display UNIX manuals  .Nd format and display UNIX manuals
 .Sh SYNOPSIS  .Sh SYNOPSIS
 .Nm mandoc  .Nm mandoc
 .Op Fl V  .Op Fl acfhkl
   .Sm off
   .Op Fl I Cm os Li = Ar name
   .Sm on
   .Op Fl K Ns Ar encoding
 .Op Fl m Ns Ar format  .Op Fl m Ns Ar format
 .Op Fl O Ns Ar option  .Op Fl O Ns Ar option
 .Op Fl T Ns Ar output  .Op Fl T Ns Ar output
 .Op Fl W Ns Ar level  .Op Fl W Ns Ar level
 .Op Ar file...  .Op Ar
 .Sh DESCRIPTION  .Sh DESCRIPTION
 The  The
 .Nm  .Nm
 utility formats  utility formats
 .Ux  .Ux
 manual pages for display.  manual pages for display.
 The arguments are as follows:  .Pp
   By default,
   .Nm
   reads
   .Xr mdoc 7
   or
   .Xr man 7
   text from stdin, implying
   .Fl m Ns Cm andoc ,
   and produces
   .Fl T Ns Cm locale
   output.
   .Pp
   The options are as follows:
 .Bl -tag -width Ds  .Bl -tag -width Ds
   .It Fl a
   If the standard output is a terminal device and
   .Fl c
   is not specified, use
   .Xr more 1
   to paginate the output, just like
   .Xr man 1
   would.
   .It Fl c
   Copy the formatted manual pages to the standard output without using
   .Xr more 1
   to paginate them.
   This is the default.
   It can be specified to override
   .Fl a .
   .It Fl f
   A synonym for
   .Xr whatis 1 .
   This overrides any earlier
   .Fl k
   and
   .Fl l
   options.
   .Sm off
   .It Fl I Cm os Li = Ar name
   .Sm on
   Override the default operating system
   .Ar name
   for the
   .Xr mdoc 7
   .Sq \&Os
   and for the
   .Xr man 7
   .Sq \&TH
   macro.
   .It Fl h
   Display only the SYNOPSIS lines.
   Implies
   .Fl c .
   .It Fl K Ns Ar encoding
   Specify the input encoding.
   The supported
   .Ar encoding
   arguments are
   .Cm us-ascii ,
   .Cm iso-8859-1 ,
   and
   .Cm utf-8 .
   If not specified, autodetection uses the first match:
   .Bl -tag -width iso-8859-1
   .It Cm utf-8
   if the first three bytes of the input file
   are the UTF-8 byte order mark (BOM, 0xefbbbf)
   .It Ar encoding
   if the first or second line of the input file matches the
   .Sy emacs
   mode line format
   .Pp
   .D1 .\e" -*- Oo ...; Oc coding: Ar encoding ; No -*-
   .It Cm utf-8
   if the first non-ASCII byte in the file introduces a valid UTF-8 sequence
   .It Cm iso-8859-1
   otherwise
   .El
   .It Fl k
   A synonym for
   .Xr apropos 1 .
   This overrides any earlier
   .Fl f
   and
   .Fl l
   options.
   .It Fl l
   A synonym for
   .Fl a .
   Also reverts any earlier
   .Fl f
   and
   .Fl k
   options.
 .It Fl m Ns Ar format  .It Fl m Ns Ar format
 Input format.  Input format.
 See  See
Line 51  See
Line 149  See
 .Sx Output Formats  .Sx Output Formats
 for available formats.  for available formats.
 Defaults to  Defaults to
 .Fl T Ns Cm ascii .  .Fl T Ns Cm locale .
 .It Fl V  
 Print version and exit.  
 .It Fl W Ns Ar level  .It Fl W Ns Ar level
 Specify the minimum message  Specify the minimum message
 .Ar level  .Ar level
Line 64  can be
Line 160  can be
 .Cm warning ,  .Cm warning ,
 .Cm error ,  .Cm error ,
 or  or
 .Cm fatal .  .Cm unsupp ;
 The default is  .Cm all
 .Fl W Ns Cm fatal ;  
 .Fl W Ns Cm all  
 is an alias for  is an alias for
 .Fl W Ns Cm warning .  .Cm warning .
   By default,
   .Nm
   is silent.
 See  See
 .Sx EXIT STATUS  .Sx EXIT STATUS
 and  and
Line 97  If multiple files are specified,
Line 194  If multiple files are specified,
 will halt with the first failed parse.  will halt with the first failed parse.
 .El  .El
 .Pp  .Pp
 By default,  In
   .Fl f
   and
   .Fl k
   mode,
 .Nm  .Nm
 reads  also supports the options
 .Xr mdoc 7  .Fl CMmOSsw
 or  described in the
 .Xr man 7  .Xr apropos 1
 text from stdin, implying  manual.
 .Fl m Ns Cm andoc ,  
 and produces  
 .Fl T Ns Cm ascii  
 output.  
 .Ss Input Formats  .Ss Input Formats
 The  The
 .Nm  .Nm
Line 157  The
Line 254  The
 utility accepts the following  utility accepts the following
 .Fl T  .Fl T
 arguments, which correspond to output modes:  arguments, which correspond to output modes:
 .Bl -tag -width Ds  .Bl -tag -width "-Tlocale"
 .It Fl T Ns Cm locale  
 This option encodes output characters using the current  
 .Xr locale 1  
 configuration.  
 See  
 .Sx Locale Output .  
 .It Fl T Ns Cm ascii  .It Fl T Ns Cm ascii
 Produce 7-bit ASCII output.  Produce 7-bit ASCII output.
 This is the default.  
 See  See
 .Sx ASCII Output .  .Sx ASCII Output .
 .It Fl T Ns Cm html  .It Fl T Ns Cm html
 Produce strict CSS1/HTML-4.01 output.  Produce HTML5, CSS1, and MathML output.
 See  See
 .Sx HTML Output .  .Sx HTML Output .
 .It Fl T Ns Cm lint  .It Fl T Ns Cm lint
 Parse only: produce no output.  Parse only: produce no output.
 Implies  Implies
 .Fl W Ns Cm warning .  .Fl W Ns Cm warning .
   .It Fl T Ns Cm locale
   Encode output using the current locale.
   This is the default.
   See
   .Sx Locale Output .
   .It Fl T Ns Cm man
   Produce
   .Xr man 7
   format output.
   See
   .Sx Man Output .
 .It Fl T Ns Cm pdf  .It Fl T Ns Cm pdf
 Produce PDF output.  Produce PDF output.
 See  See
Line 187  See
Line 288  See
 .Sx PostScript Output .  .Sx PostScript Output .
 .It Fl T Ns Cm tree  .It Fl T Ns Cm tree
 Produce an indented parse tree.  Produce an indented parse tree.
 .It Fl T Ns Cm xhtml  .It Fl T Ns Cm utf8
 Produce strict CSS1/XHTML-1.0 output.  Encode output in the UTF\-8 multi-byte format.
 See  See
 .Sx XHTML Output .  .Sx UTF\-8 Output .
   .It Fl T Ns Cm xhtml
   This is a synonym for
   .Fl T Ns Cm html .
 .El  .El
 .Pp  .Pp
 If multiple input files are specified, these will be processed by the  If multiple input files are specified, these will be processed by the
 corresponding filter in-order.  corresponding filter in-order.
 .Ss Locale Output  
 Locale-depending output encoding is triggered with  
 .Fl T Ns Cm locale .  
 This option is not available on all systems: systems without locale  
 support, or those whose internal representation is not natively UCS-4,  
 will fall back to  
 .Fl T Ns Cm ascii .  
 See  
 .Sx ASCII Output  
 for font style specification and available command-line arguments.  
 .Ss ASCII Output  .Ss ASCII Output
 Output produced by  Output produced by
 .Fl T Ns Cm ascii ,  .Fl T Ns Cm ascii
 which is the default, is rendered in standard 7-bit ASCII documented in  is rendered in standard 7-bit ASCII documented in
 .Xr ascii 7 .  .Xr ascii 7 .
 .Pp  .Pp
 Font styles are applied by using back-spaced encoding such that an  Font styles are applied by using back-spaced encoding such that an
Line 225  Emboldened characters are rendered as
Line 319  Emboldened characters are rendered as
 The special characters documented in  The special characters documented in
 .Xr mandoc_char 7  .Xr mandoc_char 7
 are rendered best-effort in an ASCII equivalent.  are rendered best-effort in an ASCII equivalent.
 If no equivalent is found,  
 .Sq \&?  
 is used instead.  
 .Pp  .Pp
 Output width is limited to 78 visible columns unless literal input lines  Output width is limited to 78 visible columns unless literal input lines
 exceed this limit.  exceed this limit.
Line 236  The following
Line 327  The following
 .Fl O  .Fl O
 arguments are accepted:  arguments are accepted:
 .Bl -tag -width Ds  .Bl -tag -width Ds
   .It Cm indent Ns = Ns Ar indent
   The left margin for normal text is set to
   .Ar indent
   blank characters instead of the default of five for
   .Xr mdoc 7
   and seven for
   .Xr man 7 .
   Increasing this is not recommended; it may result in degraded formatting,
   for example overfull lines or ugly line breaks.
 .It Cm width Ns = Ns Ar width  .It Cm width Ns = Ns Ar width
 The output width is set to  The output width is set to
 .Ar width ,  .Ar width ,
 which will normalise to \(>=60.  which will normalise to \(>=58.
 .El  .El
 .Ss HTML Output  .Ss HTML Output
 Output produced by  Output produced by
 .Fl T Ns Cm html  .Fl T Ns Cm html
 conforms to HTML-4.01 strict.  conforms to HTML5 using optional self-closing tags.
   Default styles use only CSS1.
   Equations rendered from
   .Xr eqn 7
   blocks use MathML.
 .Pp  .Pp
 The  The
 .Pa example.style.css  .Pa example.style.css
Line 252  file documents style-sheet classes available for custo
Line 356  file documents style-sheet classes available for custo
 If a style-sheet is not specified with  If a style-sheet is not specified with
 .Fl O Ns Ar style ,  .Fl O Ns Ar style ,
 .Fl T Ns Cm html  .Fl T Ns Cm html
 defaults to simple output readable in any graphical or text-based web  defaults to simple output (via an embedded style-sheet)
   readable in any graphical or text-based web
 browser.  browser.
 .Pp  .Pp
 Special characters are rendered in decimal-encoded UTF-8.  Special characters are rendered in decimal-encoded UTF\-8.
 .Pp  .Pp
 The following  The following
 .Fl O  .Fl O
 arguments are accepted:  arguments are accepted:
 .Bl -tag -width Ds  .Bl -tag -width Ds
   .It Cm fragment
   Omit the <!DOCTYPE> declaration and the <html>, <head>, and <body>
   elements and only emit the subtree below the <body> element.
   The
   .Cm style
   argument will be ignored.
   This is useful when embedding manual content within existing documents.
 .It Cm includes Ns = Ns Ar fmt  .It Cm includes Ns = Ns Ar fmt
 The string  The string
 .Ar fmt ,  .Ar fmt ,
Line 297  is used for an external style-sheet.
Line 409  is used for an external style-sheet.
 This must be a valid absolute or  This must be a valid absolute or
 relative URI.  relative URI.
 .El  .El
   .Ss Locale Output
   Locale-depending output encoding is triggered with
   .Fl T Ns Cm locale .
   This is the default.
   .Pp
   This option is not available on all systems: systems without locale
   support, or those whose internal representation is not natively UCS-4,
   will fall back to
   .Fl T Ns Cm ascii .
   See
   .Sx ASCII Output
   for font style specification and available command-line arguments.
   .Ss Man Output
   Translate input format into
   .Xr man 7
   output format.
   This is useful for distributing manual sources to legacy systems
   lacking
   .Xr mdoc 7
   formatters.
   .Pp
   If
   .Xr mdoc 7
   is passed as input, it is translated into
   .Xr man 7 .
   If the input format is
   .Xr man 7 ,
   the input is copied to the output, expanding any
   .Xr roff 7
   .Sq so
   requests.
   The parser is also run, and as usual, the
   .Fl W
   level controls which
   .Sx DIAGNOSTICS
   are displayed before copying the input to the output.
   .Ss PDF Output
   PDF-1.1 output may be generated by
   .Fl T Ns Cm pdf .
   See
   .Sx PostScript Output
   for
   .Fl O
   arguments and defaults.
 .Ss PostScript Output  .Ss PostScript Output
 PostScript  PostScript
 .Qq Adobe-3.0  .Qq Adobe-3.0
Line 331  If an unknown value is encountered,
Line 487  If an unknown value is encountered,
 .Ar letter  .Ar letter
 is used.  is used.
 .El  .El
 .Ss PDF Output  .Ss UTF\-8 Output
 PDF-1.1 output may be generated by  Use
 .Fl T Ns Cm pdf .  .Fl T Ns Cm utf8
   to force a UTF\-8 locale.
 See  See
 .Sx PostScript Output  .Sx Locale Output
 for  for details and options.
 .Fl O  .Sh ENVIRONMENT
 arguments and defaults.  .Bl -tag -width MANPAGER
 .Ss XHTML Output  .It Ev MANPAGER
 Output produced by  Any non-empty value of the environment variable
 .Fl T Ns Cm xhtml  .Ev MANPAGER
 conforms to XHTML-1.0 strict.  will be used instead of the standard pagination program,
 .Pp  .Xr more 1 .
 See  .It Ev PAGER
 .Sx HTML Output  Specifies the pagination program to use when
 for details; beyond generating XHTML tags instead of HTML tags, these  .Ev MANPAGER
 output modes are identical.  is not defined.
   If neither PAGER nor MANPAGER is defined,
   .Pa /usr/bin/more Fl s
   will be used.
   .El
 .Sh EXIT STATUS  .Sh EXIT STATUS
 The  The
 .Nm  .Nm
Line 367  At least one warning occurred, but no error, and
Line 528  At least one warning occurred, but no error, and
 .Fl W Ns Cm warning  .Fl W Ns Cm warning
 was specified.  was specified.
 .It 3  .It 3
 At least one parsing error occurred, but no fatal error, and  At least one parsing error occurred,
   but no unsupported feature was encountered, and
 .Fl W Ns Cm error  .Fl W Ns Cm error
 or  or
 .Fl W Ns Cm warning  .Fl W Ns Cm warning
 was specified.  was specified.
 .It 4  .It 4
 A fatal parsing error occurred.  At least one unsupported feature was encountered, and
   .Fl W Ns Cm unsupp ,
   .Fl W Ns Cm error
   or
   .Fl W Ns Cm warning
   was specified.
 .It 5  .It 5
 Invalid command line arguments were specified.  Invalid command line arguments were specified.
 No input files have been read.  No input files have been read.
 .It 6  .It 6
 An operating system error occurred, for example memory exhaustion or an  An operating system error occurred, for example exhaustion
 error accessing input files.  of memory, file descriptors, or process table entries.
 Such errors cause  Such errors cause
 .Nm  .Nm
 to exit at once, possibly in the middle of parsing or formatting a file.  to exit at once, possibly in the middle of parsing or formatting a file.
Line 408  To check over a large set of manuals:
Line 575  To check over a large set of manuals:
 To produce a series of PostScript manuals for A4 paper:  To produce a series of PostScript manuals for A4 paper:
 .Pp  .Pp
 .Dl $ mandoc \-Tps \-Opaper=a4 mdoc.7 man.7 \*(Gt manuals.ps  .Dl $ mandoc \-Tps \-Opaper=a4 mdoc.7 man.7 \*(Gt manuals.ps
   .Pp
   Convert a modern
   .Xr mdoc 7
   manual to the older
   .Xr man 7
   format, for use on systems lacking an
   .Xr mdoc 7
   parser:
   .Pp
   .Dl $ mandoc \-Tman foo.mdoc \*(Gt foo.man
 .Sh DIAGNOSTICS  .Sh DIAGNOSTICS
 Standard error messages reporting parsing errors are prefixed by  Messages displayed by
   .Nm
   follow this format:
 .Pp  .Pp
 .Sm off  .D1 Nm Ns : Ar file : Ns Ar line : Ns Ar column : level : message : macro args
 .D1 Ar file : line : column : \ level :  
 .Sm on  
 .Pp  .Pp
 where the fields have the following meanings:  Line and column numbers start at 1.
 .Bl -tag -width "column"  Both are omitted for messages referring to an input file as a whole.
 .It Ar file  Macro names and arguments are omitted where meaningless.
 The name of the input file causing the message.  Fatal messages about invalid command line arguments
 .It Ar line  or operating system errors, for example when memory is exhausted,
 The line number in that input file.  may also omit the
 Line numbering starts at 1.  .Ar file
 .It Ar column  and
 The column number in that input file.  .Ar level
 Column numbering starts at 1.  fields.
 If the issue is caused by a word, the column number usually  
 points to the first character of the word.  
 .It Ar level  
 The message level, printed in capital letters.  
 .El  
 .Pp  .Pp
 Message levels have the following meanings:  Message levels have the following meanings:
 .Bl -tag -width "warning"  .Bl -tag -width "warning"
 .It Cm fatal  .It Cm unsupp
 The parser is unable to parse a given input file at all.  An input file uses unsupported low-level
 No formatted output is produced from that input file.  .Xr roff 7
 .It Cm error  features.
 An input file contains syntax that cannot be safely interpreted,  The output may be incomplete and/or misformatted,
 either because it is invalid or because  so using GNU troff instead of
 .Nm  .Nm
 does not implement it yet.  to process the file may be preferable.
   .It Cm error
   An input file contains invalid syntax that cannot be safely interpreted.
 By discarding part of the input or inserting missing tokens,  By discarding part of the input or inserting missing tokens,
 the parser is able to continue, and the error does not prevent  the parser is able to continue, and the error does not prevent
 generation of formatted output, but typically, preparing that  generation of formatted output, but typically, preparing that
 output involves information loss, broken document structure  output involves information loss, broken document structure
 or unintended formatting.  or unintended formatting, no matter whether
   .Nm
   or GNU troff is used.
   In many cases, the output of
   .Nm
   and GNU troff is identical, but in some,
   .Nm
   is more resilient than GNU troff with respect to malformed input.
   .Pp
   Non-existent or unreadable input files are also reported on the
   .Cm error
   level.
   In that case, the parser cannot even be started and no output
   is produced from those input files.
 .It Cm warning  .It Cm warning
 An input file uses obsolete, discouraged or non-portable syntax.  An input file uses obsolete, discouraged or non-portable syntax.
 All the same, the meaning of the input is unambiguous and a correct  All the same, the meaning of the input is unambiguous and a correct
Line 456  formatting tools instead of
Line 643  formatting tools instead of
 .El  .El
 .Pp  .Pp
 Messages of the  Messages of the
 .Cm warning  .Cm warning ,
   .Cm error ,
 and  and
 .Cm error  .Cm unsupp
 levels are hidden unless their level, or a lower level, is requested using a  levels except those about non-existent or unreadable input files
   are hidden unless their level, or a lower level, is requested using a
 .Fl W  .Fl W
 option or  option or
 .Fl T Ns Cm lint  .Fl T Ns Cm lint
 output mode.  output mode.
 .Pp  .Ss Warnings related to the document prologue
   .Bl -ohang
   .It Sy "missing manual title, using UNTITLED"
   .Pq mdoc
   A
   .Ic \&Dt
   macro has no arguments, or there is no
   .Ic \&Dt
   macro before the first non-prologue macro.
   .It Sy "missing manual title, using \(dq\(dq"
   .Pq man
   There is no
   .Ic \&TH
   macro, or it has no arguments.
   .It Sy "lower case character in document title"
   .Pq mdoc , man
   The title is still used as given in the
   .Ic \&Dt
   or
   .Ic \&TH
   macro.
   .It Sy "missing manual section, using \(dq\(dq"
   .Pq mdoc , man
   A
   .Ic \&Dt
   or
   .Ic \&TH
   macro lacks the mandatory section argument.
   .It Sy "unknown manual section"
   .Pq mdoc
   The section number in a
   .Ic \&Dt
   line is invalid, but still used.
   .It Sy "missing date, using today's date"
   .Pq mdoc, man
   The document was parsed as
   .Xr mdoc 7
   and it has no
   .Ic \&Dd
   macro, or the
   .Ic \&Dd
   macro has no arguments or only empty arguments;
   or the document was parsed as
   .Xr man 7
   and it has no
   .Ic \&TH
   macro, or the
   .Ic \&TH
   macro has less than three arguments or its third argument is empty.
   .It Sy "cannot parse date, using it verbatim"
   .Pq mdoc , man
   The date given in a
   .Ic \&Dd
   or
   .Ic \&TH
   macro does not follow the conventional format.
   .It Sy "missing Os macro, using \(dq\(dq"
   .Pq mdoc
   The default or current system is not shown in this case.
   .It Sy "duplicate prologue macro"
   .Pq mdoc
   One of the prologue macros occurs more than once.
   The last instance overrides all previous ones.
   .It Sy "late prologue macro"
   .Pq mdoc
   A
   .Ic \&Dd
   or
   .Ic \&Os
   macro occurs after some non-prologue macro, but still takes effect.
   .It Sy "skipping late title macro"
   .Pq mdoc
 The  The
 .Nm  .Ic \&Dt
 utility may also print messages related to invalid command line arguments  macro appears after the first non-prologue macro.
 or operating system errors, for example when memory is exhausted or  Traditional formatters cannot handle this because
 input files cannot be read.  they write the page header before parsing the document body.
 Such messages do not carry the prefix described above.  Even though this technical restriction does not apply to
 .Sh COMPATIBILITY  .Nm ,
 This section summarises  traditional semantics is preserved.
 .Nm  The late macro is discarded including its arguments.
 compatibility with GNU troff.  .It Sy "prologue macros out of order"
 Each input and output format is separately noted.  .Pq mdoc
 .Ss ASCII Compatibility  The prologue macros are not given in the conventional order
 .Bl -bullet -compact  .Ic \&Dd ,
 .It  .Ic \&Dt ,
 Unrenderable unicode codepoints specified with  .Ic \&Os .
 .Sq \e[uNNNN]  All three macros are used even when given in another order.
 escapes are printed as  .El
 .Sq \&?  .Ss Warnings regarding document structure
 in mandoc.  .Bl -ohang
 In GNU troff, these raise an error.  .It Sy ".so is fragile, better use ln(1)"
 .It  .Pq roff
 The  Including files only works when the parser program runs with the correct
 .Sq \&Bd \-literal  current working directory.
   .It Sy "no document body"
   .Pq mdoc , man
   The document body contains neither text nor macros.
   An empty document is shown, consisting only of a header and a footer line.
   .It Sy "content before first section header"
   .Pq mdoc , man
   Some macros or text precede the first
   .Ic \&Sh
   or
   .Ic \&SH
   section header.
   The offending macros and text are parsed and added to the top level
   of the syntax tree, outside any section block.
   .It Sy "first section is not NAME"
   .Pq mdoc
   The argument of the first
   .Ic \&Sh
   macro is not
   .Sq NAME .
   This may confuse
   .Xr makewhatis 8
 and  and
 .Sq \&Bd \-unfilled  .Xr apropos 1 .
 macros of  .It Sy "NAME section without name"
   .Pq mdoc
   The NAME section does not contain any
   .Ic \&Nm
   child macro.
   .It Sy "NAME section without description"
   .Pq mdoc
   The NAME section lacks the mandatory
   .Ic \&Nd
   child macro.
   .It Sy "description not at the end of NAME"
   .Pq mdoc
   The NAME section does contain an
   .Ic \&Nd
   child macro, but other content follows it.
   .It Sy "bad NAME section content"
   .Pq mdoc
   The NAME section contains plain text or macros other than
   .Ic \&Nm
   and
   .Ic \&Nd .
   .It Sy "missing description line, using \(dq\(dq"
   .Pq mdoc
   The
   .Ic \&Nd
   macro lacks the required argument.
   The title line of the manual will end after the dash.
   .It Sy "sections out of conventional order"
   .Pq mdoc
   A standard section occurs after another section it usually precedes.
   All section titles are used as given,
   and the order of sections is not changed.
   .It Sy "duplicate section title"
   .Pq mdoc
   The same standard section title occurs more than once.
   .It Sy "unexpected section"
   .Pq mdoc
   A standard section header occurs in a section of the manual
   where it normally isn't useful.
   .It Sy "unusual Xr order"
   .Pq mdoc
   In the SEE ALSO section, an
   .Ic \&Xr
   macro with a lower section number follows one with a higher number,
   or two
   .Ic \&Xr
   macros refering to the same section are out of alphabetical order.
   .It Sy "unusual Xr punctuation"
   .Pq mdoc
   In the SEE ALSO section, punctuation between two
   .Ic \&Xr
   macros differs from a single comma, or there is trailing punctuation
   after the last
   .Ic \&Xr
   macro.
   .It Sy "AUTHORS section without An macro"
   .Pq mdoc
   An AUTHORS sections contains no
   .Ic \&An
   macros, or only empty ones.
   Probably, there are author names lacking markup.
   .El
   .Ss "Warnings related to macros and nesting"
   .Bl -ohang
   .It Sy "obsolete macro"
   .Pq mdoc
   See the
 .Xr mdoc 7  .Xr mdoc 7
 in  manual for replacements.
 .Fl T Ns Cm ascii  .It Sy "macro neither callable nor escaped"
 are synonyms, as are \-filled and \-ragged.  .Pq mdoc
 .It  The name of a macro that is not callable appears on a macro line.
 In historic GNU troff, the  It is printed verbatim.
 .Sq \&Pa  If the intention is to call it, move it to its own input line;
   otherwise, escape it by prepending
   .Sq \e& .
   .It Sy "skipping paragraph macro"
   In
 .Xr mdoc 7  .Xr mdoc 7
 macro does not underline when scoped under an  documents, this happens
 .Sq \&It  .Bl -dash -compact
 in the FILES section.  
 This behaves correctly in  
 .Nm .  
 .It  .It
 A list or display following the  at the beginning and end of sections and subsections
 .Sq \&Ss  
 .Xr mdoc 7  
 macro in  
 .Fl T Ns Cm ascii  
 does not assert a prior vertical break, just as it doesn't with  
 .Sq \&Sh .  
 .It  .It
 The  right before non-compact lists and displays
 .Sq \&na  .It
   at the end of items in non-column, non-compact lists
   .It
   and for multiple consecutive paragraph macros.
   .El
   In
 .Xr man 7  .Xr man 7
 macro in  documents, it happens
 .Fl T Ns Cm ascii  .Bl -dash -compact
 has no effect.  
 .It  .It
 Words aren't hyphenated.  for empty
   .Ic \&P ,
   .Ic \&PP ,
   and
   .Ic \&LP
   macros
   .It
   for
   .Ic \&IP
   macros having neither head nor body arguments
   .It
   for
   .Ic \&br
   or
   .Ic \&sp
   right after
   .Ic \&SH
   or
   .Ic \&SS
 .El  .El
 .Ss HTML/XHTML Compatibility  .It Sy "moving paragraph macro out of list"
 .Bl -bullet -compact  .Pq mdoc
   A list item in a
   .Ic \&Bl
   list contains a trailing paragraph macro.
   The paragraph macro is moved after the end of the list.
   .It Sy "skipping no-space macro"
   .Pq mdoc
   An input line begins with an
   .Ic \&Ns
   macro.
   The macro is ignored.
   .It Sy "blocks badly nested"
   .Pq mdoc
   If two blocks intersect, one should completely contain the other.
   Otherwise, rendered output is likely to look strange in any output
   format, and rendering in SGML-based output formats is likely to be
   outright wrong because such languages do not support badly nested
   blocks at all.
   Typical examples of badly nested blocks are
   .Qq Ic \&Ao \&Bo \&Ac \&Bc
   and
   .Qq Ic \&Ao \&Bq \&Ac .
   In these examples,
   .Ic \&Ac
   breaks
   .Ic \&Bo
   and
   .Ic \&Bq ,
   respectively.
   .It Sy "nested displays are not portable"
   .Pq mdoc
   A
   .Ic \&Bd ,
   .Ic \&D1 ,
   or
   .Ic \&Dl
   display occurs nested inside another
   .Ic \&Bd
   display.
   This works with
   .Nm ,
   but fails with most other implementations.
   .It Sy "moving content out of list"
   .Pq mdoc
   A
   .Ic \&Bl
   list block contains text or macros before the first
   .Ic \&It
   macro.
   The offending children are moved before the beginning of the list.
   .It Sy ".Vt block has child macro"
   .Pq mdoc
   The
   .Ic \&Vt
   macro supports plain text arguments only.
   Formatting may be ugly and semantic searching
   for the affected content might not work.
   .It Sy "fill mode already enabled, skipping"
   .Pq man
   A
   .Ic \&fi
   request occurs even though the document is still in fill mode,
   or already switched back to fill mode.
   It has no effect.
   .It Sy "fill mode already disabled, skipping"
   .Pq man
   An
   .Ic \&nf
   request occurs even though the document already switched to no-fill mode
   and did not switch back to fill mode yet.
   It has no effect.
   .It Sy "line scope broken"
   .Pq man
   While parsing the next-line scope of the previous macro,
   another macro is found that prematurely terminates the previous one.
   The previous, interrupted macro is deleted from the parse tree.
   .El
   .Ss "Warnings related to missing arguments"
   .Bl -ohang
   .It Sy "skipping empty request"
   .Pq roff , eqn
   The macro name is missing from a macro definition request,
   or an
   .Xr eqn 7
   control statement or operation keyword lacks its required argument.
   .It Sy "conditional request controls empty scope"
   .Pq roff
   A conditional request is only useful if any of the following
   follows it on the same logical input line:
   .Bl -dash -compact
 .It  .It
 The  The
 .Sq \efP  .Sq \e{
 escape will revert the font to the previous  keyword to open a multi-line scope.
 .Sq \ef  
 escape, not to the last rendered decoration, which is now dictated by  
 CSS instead of hard-coded.  
 It also will not span past the current scope,  
 for the same reason.  
 Note that in  
 .Sx ASCII Output  
 mode, this will work fine.  
 .It  .It
   A request or macro or some text, resulting in a single-line scope.
   .It
   The immediate end of the logical line without any intervening whitespace,
   resulting in next-line scope.
   .El
   Here, a conditional request is followed by trailing whitespace only,
   and there is no other content on its logical input line.
   Note that it doesn't matter whether the logical input line is split
   across multiple physical input lines using
   .Sq \e
   line continuation characters.
   This is one of the rare cases
   where trailing whitespace is syntactically significant.
   The conditional request controls a scope containing whitespace only,
   so it is unlikely to have a significant effect,
   except that it may control a following
   .Ic \&el
   clause.
   .It Sy "skipping empty macro"
   .Pq mdoc
   The indicated macro has no arguments and hence no effect.
   .It Sy "empty block"
   .Pq mdoc , man
   A
   .Ic \&Bd ,
   .Ic \&Bk ,
   .Ic \&Bl ,
   .Ic \&D1 ,
   .Ic \&Dl ,
   .Ic \&RS ,
   or
   .Ic \&UR
   block contains nothing in its body and will produce no output.
   .It Sy "empty argument, using 0n"
   .Pq mdoc
   The required width is missing after
   .Ic \&Bd
   or
   .Ic \&Bl
   .Fl offset
   or
   .Fl width.
   .It Sy "missing display type, using -ragged"
   .Pq mdoc
 The  The
   .Ic \&Bd
   macro is invoked without the required display type.
   .It Sy "list type is not the first argument"
   .Pq mdoc
   In a
   .Ic \&Bl
   macro, at least one other argument precedes the type argument.
   The
   .Nm
   utility copes with any argument order, but some other
 .Xr mdoc 7  .Xr mdoc 7
 .Sq \&Bl \-hang  implementations do not.
   .It Sy "missing -width in -tag list, using 8n"
   .Pq mdoc
   Every
   .Ic \&Bl
   macro having the
   .Fl tag
   argument requires
   .Fl width ,
   too.
   .It Sy "missing utility name, using \(dq\(dq"
   .Pq mdoc
   The
   .Ic \&Ex Fl std
   macro is called without an argument before
   .Ic \&Nm
   has first been called with an argument.
   .It Sy "missing function name, using \(dq\(dq"
   .Pq mdoc
   The
   .Ic \&Fo
   macro is called without an argument.
   No function name is printed.
   .It Sy "empty head in list item"
   .Pq mdoc
   In a
   .Ic \&Bl
   .Fl diag ,
   .Fl hang ,
   .Fl inset ,
   .Fl ohang ,
   or
   .Fl tag
   list, an
   .Ic \&It
   macro lacks the required argument.
   The item head is left empty.
   .It Sy "empty list item"
   .Pq mdoc
   In a
   .Ic \&Bl
   .Fl bullet ,
   .Fl dash ,
   .Fl enum ,
   or
   .Fl hyphen
   list, an
   .Ic \&It
   block is empty.
   An empty list item is shown.
   .It Sy "missing font type, using \efR"
   .Pq mdoc
   A
   .Ic \&Bf
   macro has no argument.
   It switches to the default font.
   .It Sy "unknown font type, using \efR"
   .Pq mdoc
   The
   .Ic \&Bf
   argument is invalid.
   The default font is used instead.
   .It Sy "nothing follows prefix"
   .Pq mdoc
   A
   .Ic \&Pf
   macro has no argument, or only one argument and no macro follows
   on the same input line.
   This defeats its purpose; in particular, spacing is not suppressed
   before the text or macros following on the next input line.
   .It Sy "empty reference block"
   .Pq mdoc
   An
   .Ic \&Rs
   macro is immediately followed by an
   .Ic \&Re
   macro on the next input line.
   Such an empty block does not produce any output.
   .It Sy "missing -std argument, adding it"
   .Pq mdoc
   An
   .Ic \&Ex
   or
   .Ic \&Rv
   macro lacks the required
   .Fl std
   argument.
   The
   .Nm
   utility assumes
   .Fl std
   even when it is not specified, but other implementations may not.
   .It Sy "missing option string, using \(dq\(dq"
   .Pq man
   The
   .Ic \&OP
   macro is invoked without any argument.
   An empty pair of square brackets is shown.
   .It Sy "missing resource identifier, using \(dq\(dq"
   .Pq man
   The
   .Ic \&UR
   macro is invoked without any argument.
   An empty pair of angle brackets is shown.
   .It Sy "missing eqn box, using \(dq\(dq"
   .Pq eqn
   A diacritic mark or a binary operator is found,
   but there is nothing to the left of it.
   An empty box is inserted.
   .El
   .Ss "Warnings related to bad macro arguments"
   .Bl -ohang
   .It Sy "unterminated quoted argument"
   .Pq roff
   Macro arguments can be enclosed in double quote characters
   such that space characters and macro names contained in the quoted
   argument need not be escaped.
   The closing quote of the last argument of a macro can be omitted.
   However, omitting it is not recommended because it makes the code
   harder to read.
   .It Sy "duplicate argument"
   .Pq mdoc
   A
   .Ic \&Bd
   or
   .Ic \&Bl
   macro has more than one
   .Fl compact ,
   more than one
   .Fl offset ,
   or more than one
   .Fl width
   argument.
   All but the last instances of these arguments are ignored.
   .It Sy "skipping duplicate argument"
   .Pq mdoc
   An
   .Ic \&An
   macro has more than one
   .Fl split
   or
   .Fl nosplit
   argument.
   All but the first of these arguments are ignored.
   .It Sy "skipping duplicate display type"
   .Pq mdoc
   A
   .Ic \&Bd
   macro has more than one type argument; the first one is used.
   .It Sy "skipping duplicate list type"
   .Pq mdoc
   A
   .Ic \&Bl
   macro has more than one type argument; the first one is used.
   .It Sy "skipping -width argument"
   .Pq mdoc
   A
   .Ic \&Bl
   .Fl column ,
   .Fl diag ,
   .Fl ohang ,
   .Fl inset ,
   or
   .Fl item
   list has a
   .Fl width
   argument.
   That has no effect.
   .It Sy "wrong number of cells"
   In a line of a
   .Ic \&Bl Fl column
   list, the number of tabs or
   .Ic \&Ta
   macros is less than the number expected from the list header line
   or exceeds the expected number by more than one.
   Missing cells remain empty, and all cells exceeding the number of
   columns are joined into one single cell.
   .It Sy "unknown AT&T UNIX version"
   .Pq mdoc
   An
   .Ic \&At
   macro has an invalid argument.
   It is used verbatim, with
   .Qq "AT&T UNIX "
   prefixed to it.
   .It Sy "comma in function argument"
   .Pq mdoc
   An argument of an
   .Ic \&Fa
   or
   .Ic \&Fn
   macro contains a comma; it should probably be split into two arguments.
   .It Sy "parenthesis in function name"
   .Pq mdoc
   The first argument of an
   .Ic \&Fc
   or
   .Ic \&Fn
   macro contains an opening or closing parenthesis; that's probably wrong,
   parentheses are added automatically.
   .It Sy "invalid content in Rs block"
   .Pq mdoc
   An
   .Ic \&Rs
   block contains plain text or non-% macros.
   The bogus content is left in the syntax tree.
   Formatting may be poor.
   .It Sy "invalid Boolean argument"
   .Pq mdoc
   An
   .Ic \&Sm
   macro has an argument other than
   .Cm on
   or
   .Cm off .
   The invalid argument is moved out of the macro, which leaves the macro
   empty, causing it to toggle the spacing mode.
   .It Sy "unknown font, skipping request"
   .Pq man , tbl
   A
   .Xr roff 7
   .Ic \&ft
   request or a
   .Xr tbl 7
   .Ic \&f
   layout modifier has an unknown
   .Ar font
   argument.
   .It Sy "odd number of characters in request"
   .Pq roff
   A
   .Ic \&tr
   request contains an odd number of characters.
   The last character is mapped to the blank character.
   .El
   .Ss "Warnings related to plain text"
   .Bl -ohang
   .It Sy "blank line in fill mode, using .sp"
   .Pq mdoc
   The meaning of blank input lines is only well-defined in non-fill mode:
   In fill mode, line breaks of text input lines are not supposed to be
   significant.
   However, for compatibility with groff, blank lines in fill mode
   are replaced with
   .Ic \&sp
   requests.
   .It Sy "tab in filled text"
   .Pq mdoc , man
   The meaning of tab characters is only well-defined in non-fill mode:
   In fill mode, whitespace is not supposed to be significant
   on text input lines.
   As an implementation dependent choice, tab characters on text lines
   are passed through to the formatters in any case.
   Given that the text before the tab character will be filled,
   it is hard to predict which tab stop position the tab will advance to.
   .It Sy "whitespace at end of input line"
   .Pq mdoc , man , roff
   Whitespace at the end of input lines is almost never semantically
   significant \(em but in the odd case where it might be, it is
   extremely confusing when reviewing and maintaining documents.
   .It Sy "bad comment style"
   .Pq roff
   Comment lines start with a dot, a backslash, and a double-quote character.
   The
   .Nm
   utility treats the line as a comment line even without the backslash,
   but leaving out the backslash might not be portable.
   .It Sy "invalid escape sequence"
   .Pq roff
   An escape sequence has an invalid opening argument delimiter, lacks the
   closing argument delimiter, or the argument has too few characters.
   If the argument is incomplete,
   .Ic \e*
 and  and
 .Sq \&Bl \-tag  .Ic \en
 list types render similarly (no break following overreached left-hand  expand to an empty string,
 side) due to the expressive constraints of HTML.  .Ic \eB
   to the digit
   .Sq 0 ,
   and
   .Ic \ew
   to the length of the incomplete argument.
   All other invalid escape sequences are ignored.
   .It Sy "undefined string, using \(dq\(dq"
   .Pq roff
   If a string is used without being defined before,
   its value is implicitly set to the empty string.
   However, defining strings explicitly before use
   keeps the code more readable.
   .El
   .Ss "Warnings related to tables"
   .Bl -ohang
   .It Sy "tbl line starts with span"
   .Pq tbl
   The first cell in a table layout line is a horizontal span
   .Pq Sq Cm s .
   Data provided for this cell is ignored, and nothing is printed in the cell.
   .It Sy "tbl column starts with span"
   .Pq tbl
   The first line of a table layout specification
   requests a vertical span
   .Pq Sq Cm ^ .
   Data provided for this cell is ignored, and nothing is printed in the cell.
   .It Sy "skipping vertical bar in tbl layout"
   .Pq tbl
   A table layout specification contains more than two consecutive vertical bars.
   A double bar is printed, all additional bars are discarded.
   .El
   .Ss "Errors related to tables"
   .Bl -ohang
   .It Sy "non-alphabetic character in tbl options"
   .Pq tbl
   The table options line contains a character other than a letter,
   blank, or comma where the beginning of an option name is expected.
   The character is ignored.
   .It Sy "skipping unknown tbl option"
   .Pq tbl
   The table options line contains a string of letters that does not
   match any known option name.
   The word is ignored.
   .It Sy "missing tbl option argument"
   .Pq tbl
   A table option that requires an argument is not followed by an
   opening parenthesis, or the opening parenthesis is immediately
   followed by a closing parenthesis.
   The option is ignored.
   .It Sy "wrong tbl option argument size"
   .Pq tbl
   A table option argument contains an invalid number of characters.
   Both the option and the argument are ignored.
   .It Sy "empty tbl layout"
   .Pq tbl
   A table layout specification is completely empty,
   specifying zero lines and zero columns.
   As a fallback, a single left-justified column is used.
   .It Sy "invalid character in tbl layout"
   .Pq tbl
   A table layout specification contains a character that can neither
   be interpreted as a layout key character nor as a layout modifier,
   or a modifier precedes the first key.
   The invalid character is discarded.
   .It Sy "unmatched parenthesis in tbl layout"
   .Pq tbl
   A table layout specification contains an opening parenthesis,
   but no matching closing parenthesis.
   The rest of the input line, starting from the parenthesis, has no effect.
   .It Sy "tbl without any data cells"
   .Pq tbl
   A table does not contain any data cells.
   It will probably produce no output.
   .It Sy "ignoring data in spanned tbl cell"
   .Pq tbl
   A table cell is marked as a horizontal span
   .Pq Sq Cm s
   or vertical span
   .Pq Sq Cm ^
   in the table layout, but it contains data.
   The data is ignored.
   .It Sy "ignoring extra tbl data cells"
   .Pq tbl
   A data line contains more cells than the corresponding layout line.
   The data in the extra cells is ignored.
   .It Sy "data block open at end of tbl"
   .Pq tbl
   A data block is opened with
   .Cm T{ ,
   but never closed with a matching
   .Cm T} .
   The remaining data lines of the table are all put into one cell,
   and any remaining cells stay empty.
   .El
   .Ss "Errors related to roff, mdoc, and man code"
   .Bl -ohang
   .It Sy "input stack limit exceeded, infinite loop?"
   .Pq roff
   Explicit recursion limits are implemented for the following features,
   in order to prevent infinite loops:
   .Bl -dash -compact
 .It  .It
   expansion of nested escape sequences
   including expansion of strings and number registers,
   .It
   expansion of nested user-defined macros,
   .It
   and
   .Ic \&so
   file inclusion.
   .El
   When a limit is hit, the output is incorrect, typically losing
   some content, but the parser can continue.
   .It Sy "skipping bad character"
   .Pq mdoc , man , roff
   The input file contains a byte that is not a printable
   .Xr ascii 7
   character.
   The message mentions the character number.
   The offending byte is replaced with a question mark
   .Pq Sq \&? .
   Consider editing the input file to replace the byte with an ASCII
   transliteration of the intended character.
   .It Sy "skipping unknown macro"
   .Pq mdoc , man , roff
   The first identifier on a request or macro line is neither recognized as a
   .Xr roff 7
   request, nor as a user-defined macro, nor, respectively, as an
   .Xr mdoc 7
   or
   .Xr man 7
   macro.
   It may be mistyped or unsupported.
   The request or macro is discarded including its arguments.
   .It Sy "skipping insecure request"
   .Pq roff
   An input file attempted to run a shell command
   or to read or write an external file.
   Such attempts are denied for security reasons.
   .It Sy "skipping item outside list"
   .Pq mdoc , eqn
   An
   .Ic \&It
   macro occurs outside any
   .Ic \&Bl
   list, or an
   .Xr eqn 7
   .Ic above
   delimiter occurs outside any pile.
   It is discarded including its arguments.
   .It Sy "skipping column outside column list"
   .Pq mdoc
   A
   .Ic \&Ta
   macro occurs outside any
   .Ic \&Bl Fl column
   block.
   It is discarded including its arguments.
   .It Sy "skipping end of block that is not open"
   .Pq mdoc , man , eqn , tbl , roff
   Various syntax elements can only be used to explicitly close blocks
   that have previously been opened.
   An
   .Xr mdoc 7
   block closing macro, a
   .Xr man 7
   .Ic \&RE
   or
   .Ic \&UE
   macro, an
   .Xr eqn 7
   right delimiter or closing brace, or the end of an equation, table, or
   .Xr roff 7
   conditional request is encountered but no matching block is open.
   The offending request or macro is discarded.
   .It Sy "fewer RS blocks open, skipping"
   .Pq man
 The  The
   .Ic \&RE
   macro is invoked with an argument, but less than the specified number of
   .Ic \&RS
   blocks is open.
   The
   .Ic \&RE
   macro is discarded.
   .It Sy "inserting missing end of block"
   .Pq mdoc , tbl
   Various
   .Xr mdoc 7
   macros as well as tables require explicit closing by dedicated macros.
   A block that doesn't support bad nesting
   ends before all of its children are properly closed.
   The open child nodes are closed implicitly.
   .It Sy "appending missing end of block"
   .Pq mdoc , man , eqn , tbl , roff
   At the end of the document, an explicit
   .Xr mdoc 7
   block, a
 .Xr man 7  .Xr man 7
 .Sq IP  next-line scope or
   .Ic \&RS
   or
   .Ic \&UR
   block, an equation, table, or
   .Xr roff 7
   conditional or ignore block is still open.
   The open block is closed implicitly.
   .It Sy "escaped character not allowed in a name"
   .Pq roff
   Macro, string and register identifiers consist of printable,
   non-whitespace ASCII characters.
   Escape sequences and characters and strings expressed in terms of them
   cannot form part of a name.
   The first argument of an
   .Ic \&am ,
   .Ic \&as ,
   .Ic \&de ,
   .Ic \&ds ,
   .Ic \&nr ,
   or
   .Ic \&rr
   request, or any argument of an
   .Ic \&rm
   request, or the name of a request or user defined macro being called,
   is terminated by an escape sequence.
   In the cases of
   .Ic \&as ,
   .Ic \&ds ,
 and  and
 .Sq TP  .Ic \&nr ,
 lists render similarly.  the request has no effect at all.
   In the cases of
   .Ic \&am ,
   .Ic \&de ,
   .Ic \&rr ,
   and
   .Ic \&rm ,
   what was parsed up to this point is used as the arguments to the request,
   and the rest of the input line is discarded including the escape sequence.
   When parsing for a request or a user-defined macro name to be called,
   only the escape sequence is discarded.
   The characters preceding it are used as the request or macro name,
   the characters following it are used as the arguments to the request or macro.
   .It Sy "NOT IMPLEMENTED: Bd -file"
   .Pq mdoc
   For security reasons, the
   .Ic \&Bd
   macro does not support the
   .Fl file
   argument.
   By requesting the inclusion of a sensitive file, a malicious document
   might otherwise trick a privileged user into inadvertently displaying
   the file on the screen, revealing the file content to bystanders.
   The argument is ignored including the file name following it.
   .It Sy "missing list type, using -item"
   .Pq mdoc
   A
   .Ic \&Bl
   macro fails to specify the list type.
   .It Sy "missing manual name, using \(dq\(dq"
   .Pq mdoc
   The first call to
   .Ic \&Nm
   lacks the required argument.
   .It Sy "uname(3) system call failed, using UNKNOWN"
   .Pq mdoc
   The
   .Ic \&Os
   macro is called without arguments, and the
   .Xr uname 3
   system call failed.
   As a workaround,
   .Nm
   can be compiled with
   .Sm off
   .Fl D Cm OSNAME=\(dq\e\(dq Ar string Cm \e\(dq\(dq .
   .Sm on
   .It Sy "unknown standard specifier"
   .Pq mdoc
   An
   .Ic \&St
   macro has an unknown argument and is discarded.
   .It Sy "skipping request without numeric argument"
   .Pq roff , eqn
   An
   .Ic \&it
   request or an
   .Xr eqn 7
   .Ic \&size
   or
   .Ic \&gsize
   statement has a non-numeric or negative argument or no argument at all.
   The invalid request or statement is ignored.
   .It Sy "NOT IMPLEMENTED: .so with absolute path or \(dq..\(dq"
   .Pq roff
   For security reasons,
   .Nm
   allows
   .Ic \&so
   file inclusion requests only with relative paths
   and only without ascending to any parent directory.
   By requesting the inclusion of a sensitive file, a malicious document
   might otherwise trick a privileged user into inadvertently displaying
   the file on the screen, revealing the file content to bystanders.
   .Nm
   only shows the path as it appears behind
   .Ic \&so .
   .It Sy ".so request failed"
   .Pq roff
   Servicing a
   .Ic \&so
   request requires reading an external file, but the file could not be
   opened.
   .Nm
   only shows the path as it appears behind
   .Ic \&so .
   .It Sy "skipping all arguments"
   .Pq mdoc , man , eqn , roff
   An
   .Xr mdoc 7
   .Ic \&Bt ,
   .Ic \&Ed ,
   .Ic \&Ef ,
   .Ic \&Ek ,
   .Ic \&El ,
   .Ic \&Lp ,
   .Ic \&Pp ,
   .Ic \&Re ,
   .Ic \&Rs ,
   or
   .Ic \&Ud
   macro, an
   .Ic \&It
   macro in a list that don't support item heads, a
   .Xr man 7
   .Ic \&LP ,
   .Ic \&P ,
   or
   .Ic \&PP
   macro, an
   .Xr eqn 7
   .Ic \&EQ
   or
   .Ic \&EN
   macro, or a
   .Xr roff 7
   .Ic \&br ,
   .Ic \&fi ,
   or
   .Ic \&nf
   request or
   .Sq \&..
   block closing request is invoked with at least one argument.
   All arguments are ignored.
   .It Sy "skipping excess arguments"
   .Pq mdoc , man , roff
   A macro or request is invoked with too many arguments:
   .Bl -dash -offset 2n -width 2n -compact
   .It
   .Ic \&Fo ,
   .Ic \&PD ,
   .Ic \&RS ,
   .Ic \&UR ,
   .Ic \&ft ,
   or
   .Ic \&sp
   with more than one argument
   .It
   .Ic \&An
   with another argument after
   .Fl split
   or
   .Fl nosplit
   .It
   .Ic \&RE
   with more than one argument or with a non-integer argument
   .It
   .Ic \&OP
   or a request of the
   .Ic \&de
   family with more than two arguments
   .It
   .Ic \&Dt
   with more than three arguments
   .It
   .Ic \&TH
   with more than five arguments
   .It
   .Ic \&Bd ,
   .Ic \&Bk ,
   or
   .Ic \&Bl
   with invalid arguments
 .El  .El
   The excess arguments are ignored.
   .El
   .Ss Unsupported features
   .Bl -ohang
   .It Sy "input too large"
   .Pq mdoc , man
   Currently,
   .Nm
   cannot handle input files larger than its arbitrary size limit
   of 2^31 bytes (2 Gigabytes).
   Since useful manuals are always small, this is not a problem in practice.
   Parsing is aborted as soon as the condition is detected.
   .It Sy "unsupported control character"
   .Pq roff
   An ASCII control character supported by other
   .Xr roff 7
   implementations but not by
   .Nm
   was found in an input file.
   It is replaced by a question mark.
   .It Sy "unsupported roff request"
   .Pq roff
   An input file contains a
   .Xr roff 7
   request supported by GNU troff or Heirloom troff but not by
   .Nm ,
   and it is likely that this will cause information loss
   or considerable misformatting.
   .It Sy "eqn delim option in tbl"
   .Pq eqn , tbl
   The options line of a table defines equation delimiters.
   Any equation source code contained in the table will be printed unformatted.
   .It Sy "unsupported table layout modifier"
   .Pq tbl
   A table layout specification contains an
   .Sq Cm m
   modifier.
   The modifier is discarded.
   .It Sy "ignoring macro in table"
   .Pq tbl , mdoc , man
   A table contains an invocation of an
   .Xr mdoc 7
   or
   .Xr man 7
   macro or of an undefined macro.
   The macro is ignored, and its arguments are handled
   as if they were a text line.
   .El
 .Sh SEE ALSO  .Sh SEE ALSO
   .Xr apropos 1 ,
   .Xr man 1 ,
 .Xr eqn 7 ,  .Xr eqn 7 ,
 .Xr man 7 ,  .Xr man 7 ,
 .Xr mandoc_char 7 ,  .Xr mandoc_char 7 ,
Line 563  lists render similarly.
Line 1770  lists render similarly.
 The  The
 .Nm  .Nm
 utility was written by  utility was written by
 .An Kristaps Dzonsons Aq kristaps@bsd.lv .  .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
 .Sh CAVEATS  and is maintained by
   .An Ingo Schwarze Aq Mt schwarze@openbsd.org .
   .Sh BUGS
 In  In
 .Fl T Ns Cm html  .Fl T Ns Cm html ,
 and  
 .Fl T Ns Cm xhtml ,  
 the maximum size of an element attribute is determined by  the maximum size of an element attribute is determined by
 .Dv BUFSIZ ,  .Dv BUFSIZ ,
 which is usually 1024 bytes.  which is usually 1024 bytes.
 Be aware of this when setting long link  Be aware of this when setting long link
 formats such as  formats such as
 .Fl O Ns Cm style Ns = Ns Ar really/long/link .  .Fl O Ns Cm style Ns = Ns Ar really/long/link .
 .Pp  
 Nesting elements within next-line element scopes of  
 .Fl m Ns Cm an ,  
 such as  
 .Sq br  
 within an empty  
 .Sq B ,  
 will confuse  
 .Fl T Ns Cm html  
 and  
 .Fl T Ns Cm xhtml  
 and cause them to forget the formatting of the prior next-line scope.  
 .Pp  
 The  
 .Sq \(aq  
 control character is an alias for the standard macro control character  
 and does not emit a line-break as stipulated in GNU troff.  
Legend:
Removed from v.1.87  
changed lines
  Added in v.1.155
CVSweb