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MAN-PAGES(7)                                                            Linux Programmer's Manual                                                           MAN-PAGES(7)

NAME
       man-pages - conventions for writing Linux man pages

SYNOPSIS
       man [section] title

DESCRIPTION
       This  page  describes the conventions that should be employed when writing man pages for the Linux man-pages project, which documents the user-space API provided
       by the Linux kernel and the GNU C library.  The project thus provides most of the pages in Section 2, many of the pages that appear in Sections 3, 4, and 7,  and
       a few of the pages that appear in Sections 1, 5, and 8 of the man pages on a Linux system.  The conventions described on this page may also be useful for authors
       writing man pages for other projects.

   Sections of the manual pages
       The manual Sections are traditionally defined as follows:

       1 User commands (Programs)
              Commands that can be executed by the user from within a shell.

       2 System calls
              Functions which wrap operations performed by the kernel.

       3 Library calls
              All library functions excluding the system call wrappers (Most of the libc functions).

       4 Special files (devices)
              Files found in /dev which allow to access to devices through the kernel.

       5 File formats and configuration files
              Describes various human-readable file formats and configuration files.

       6 Games
              Games and funny little programs available on the system.

       7 Overview, conventions, and miscellaneous
              Overviews or descriptions of various topics, conventions, and protocols, character set standards, the standard filesystem layout, and miscellaneous  other
              things.

       8 System management commands
              Commands like mount(8), many of which only root can execute.

   Macro package
       New  manual  pages should be marked up using the groff an.tmac package described in man(7).  This choice is mainly for consistency: the vast majority of existing
       Linux manual pages are marked up using these macros.

   Conventions for source file layout
       Please limit source code line length to no more than about 75 characters wherever possible.  This helps avoid line-wrapping in some mail clients when patches are
       submitted inline.

   Title line
       The first command in a man page should be a TH command:

              .TH title section date source manual

       The arguments of the command are as follows:

       title  The title of the man page, written in all caps (e.g., MAN-PAGES).

       section
              The section number in which the man page should be placed (e.g., 7).

       date   The  date  of the last nontrivial change that was made to the man page.  (Within the man-pages project, the necessary updates to these timestamps are han‐
              dled automatically by scripts, so there is no need to manually update them as part of a patch.)  Dates should be written in the form YYYY-MM-DD.

       source The source of the command, function, or system call.

              For those few man-pages pages in Sections 1 and 8, probably you just want to write GNU.

              For system calls, just write Linux.  (An earlier practice was to write the version number of the kernel  from  which  the  manual  page  was  being  writ‐
              ten/checked.   However,  this was never done consistently, and so was probably worse than including no version number.  Henceforth, avoid including a ver‐
              sion number.)

              For library calls that are part of glibc or one of the other common GNU libraries, just use GNU C Library, GNU, or an empty string.

              For Section 4 pages, use Linux.

              In cases of doubt, just write Linux, or GNU.

       manual The title of the manual (e.g., for Section 2 and 3 pages in the man-pages package, use Linux Programmer's Manual).

   Sections within a manual page
       The list below shows conventional or suggested sections.  Most manual pages should include at least the highlighted sections.  Arrange a new manual page so  that
       sections are placed in the order shown in the list.

              NAME
              SYNOPSIS
              CONFIGURATION    [Normally only in Section 4]
              DESCRIPTION
              OPTIONS          [Normally only in Sections 1, 8]
              EXIT STATUS      [Normally only in Sections 1, 8]
              RETURN VALUE     [Normally only in Sections 2, 3]
              ERRORS           [Typically only in Sections 2, 3]
              ENVIRONMENT
              FILES
              VERSIONS         [Normally only in Sections 2, 3]
              ATTRIBUTES       [Normally only in Sections 2, 3]
              CONFORMING TO
              NOTES
              BUGS
              EXAMPLES
              AUTHORS          [Discouraged]
              REPORTING BUGS   [Not used in man-pages]
              COPYRIGHT        [Not used in man-pages]
              SEE ALSO

       Where a traditional heading would apply, please use it; this kind of consistency can make the information easier to understand.  If you must, you can create your
       own headings if they make things easier to understand (this can be especially useful for pages in Sections 4  and  5).   However,  before  doing  this,  consider
       whether you could use the traditional headings, with some subsections (.SS) within those sections.

       The following list elaborates on the contents of each of the above sections.

       NAME   The name of this manual page.

              See man(7) for important details of the line(s) that should follow the .SH NAME command.  All words in this line (including the word immediately following
              the "\-") should be in lowercase, except where English or technical terminological convention dictates otherwise.

       SYNOPSIS
              A brief summary of the command or function's interface.

              For commands, this shows the syntax of the command and its arguments (including options); boldface is used for as-is text and italics are used to indicate
              replaceable arguments.  Brackets ([]) surround optional arguments, vertical bars (|) separate choices, and ellipses (...) can be repeated.  For functions,
              it shows any required data declarations or #include directives, followed by the function declaration.

              Where a feature test macro must be defined in order to obtain the declaration of a function (or a variable) from a header file, then the  SYNOPSIS  should
              indicate this, as described in feature_test_macros(7).

       CONFIGURATION
              Configuration details for a device.

              This section normally appears only in Section 4 pages.

       DESCRIPTION
              An explanation of what the program, function, or format does.

              Discuss  how it interacts with files and standard input, and what it produces on standard output or standard error.  Omit internals and implementation de‐
              tails unless they're critical for understanding the interface.  Describe the usual case; for information on command-line options of a program use the  OP‐
              TIONS section.

              When  describing  new  behavior or new flags for a system call or library function, be careful to note the kernel or C library version that introduced the
              change.  The preferred method of noting this information for flags is as part of a .TP list, in the following form (here, for a new system call flag):

                       XYZ_FLAG (since Linux 3.7)
                              Description of flag...

              Including version information is especially useful to users who are constrained to using older kernel or C library versions (which is typical in  embedded
              systems, for example).

       OPTIONS
              A description of the command-line options accepted by a program and how they change its behavior.

              This section should appear only for Section 1 and 8 manual pages.

       EXIT STATUS
              A list of the possible exit status values of a program and the conditions that cause these values to be returned.

              This section should appear only for Section 1 and 8 manual pages.

       RETURN VALUE
              For  Section 2 and 3 pages, this section gives a list of the values the library routine will return to the caller and the conditions that cause these val‐
              ues to be returned.

       ERRORS For Section 2 and 3 manual pages, this is a list of the values that may be placed in errno in the event of an error,  along  with  information  about  the
              cause of the errors.

              Where several different conditions produce the same error, the preferred approach is to create separate list entries (with duplicate error names) for each
              of the conditions.  This makes the separate conditions clear, may make the list easier to read, and allows metainformation (e.g.,  kernel  version  number
              where the condition first became applicable) to be more easily marked for each condition.

              The error list should be in alphabetical order.

       ENVIRONMENT
              A list of all environment variables that affect the program or function and how they affect it.

       FILES  A list of the files the program or function uses, such as configuration files, startup files, and files the program directly operates on.

              Give  the  full  pathname of these files, and use the installation process to modify the directory part to match user preferences.  For many programs, the
              default installation location is in /usr/local, so your base manual page should use /usr/local as the base.

       ATTRIBUTES
              A summary of various attributes of the function(s) documented on this page.  See attributes(7) for further details.

       VERSIONS
              A brief summary of the Linux kernel or glibc versions where a system call or library function appeared, or changed significantly in its operation.

              As a general rule, every new interface should include a VERSIONS section in its manual page.  Unfortunately, many existing manual pages don't include this
              information  (since  there  was  no policy to do so when they were written).  Patches to remedy this are welcome, but, from the perspective of programmers
              writing new code, this information probably matters only in the case of kernel interfaces that have been added in Linux 2.4 or later (i.e., changes  since
              kernel 2.2), and library functions that have been added to glibc since version 2.1 (i.e., changes since glibc 2.0).

              The syscalls(2) manual page also provides information about kernel versions in which various system calls first appeared.

       CONFORMING TO
              A description of any standards or conventions that relate to the function or command described by the manual page.

              The preferred terms to use for the various standards are listed as headings in standards(7).

              For  a  page  in Section 2 or 3, this section should note the POSIX.1 version(s) that the call conforms to, and also whether the call is specified in C99.
              (Don't worry too much about other standards like SUS, SUSv2, and XPG, or the SVr4 and 4.xBSD implementation standards, unless the call  was  specified  in
              those standards, but isn't in the current version of POSIX.1.)

              If the call is not governed by any standards but commonly exists on other systems, note them.  If the call is Linux-specific, note this.

              If this section consists of just a list of standards (which it commonly does), terminate the list with a period ('.').

       NOTES  Miscellaneous notes.

              For Section 2 and 3 man pages you may find it useful to include subsections (SS) named Linux Notes and Glibc Notes.

              In Section 2, use the heading C library/kernel differences to mark off notes that describe the differences (if any) between the C library wrapper function
              for a system call and the raw system call interface provided by the kernel.

       BUGS   A list of limitations, known defects or inconveniences, and other questionable activities.

       EXAMPLES
              One or more examples demonstrating how this function, file, or command is used.

              For details on writing example programs, see Example programs below.

       AUTHORS
              A list of authors of the documentation or program.

              Use of an AUTHORS section is strongly discouraged.  Generally, it is better not to clutter every page with a list of (over time potentially numerous)  au‐
              thors;  if  you write or significantly amend a page, add a copyright notice as a comment in the source file.  If you are the author of a device driver and
              want to include an address for reporting bugs, place this under the BUGS section.

       REPORTING BUGS
              The man-pages project doesn't use a REPORTING BUGS section in manual pages.  Information on reporting bugs is instead  supplied  in  the  script-generated
              COLOPHON section.  However, various projects do use a REPORTING BUGS section.  It is recommended to place it near the foot of the page.

       COPYRIGHT
              The  man-pages  project  doesn't use a COPYRIGHT section in manual pages.  Copyright information is instead maintained in the page source.  In pages where
              this section is present, it is recommended to place it near the foot of the page, just above SEE ALSO.

       SEE ALSO
              A comma-separated list of related man pages, possibly followed by other related pages or documents.

              The list should be ordered by section number and then alphabetically by name.  Do not terminate this list with a period.

              Where the SEE ALSO list contains many long manual page names, to improve the visual result of the output, it may be useful to  employ  the  .ad  l  (don't
              right justify) and .nh (don't hyphenate) directives.  Hyphenation of individual page names can be prevented by preceding words with the string "\%".

              Given the distributed, autonomous nature of FOSS projects and their documentation, it is sometimes necessaryβ€”and in many cases desirableβ€”that the SEE ALSO
              section includes references to manual pages provided by other projects.

FORMATTING AND WORDING CONVENTIONS
       The following subsections note some details for preferred formatting and wording conventions in various sections of the pages in the man-pages project.

   SYNOPSIS
       Wrap the function prototype(s) in a .nf/.fi pair to prevent filling.

       In general, where more than one function prototype is shown in the SYNOPSIS, the prototypes should not  be  separated  by  blank  lines.   However,  blank  lines
       (achieved using .PP) may be added in the following cases:

       *  to separate long lists of function prototypes into related groups (see for example list(3));

       *  in other cases that may improve readability.

       In the SYNOPSIS, a long function prototype may need to be continued over to the next line.  The continuation line is indented according to the following rules:

       1. If  there  is a single such prototype that needs to be continued, then align the continuation line so that when the page is rendered on a fixed-width font de‐
          vice (e.g., on an xterm) the continuation line starts just below the start of the argument list in the line above.  (Exception: the  indentation  may  be  ad‐
          justed if necessary to prevent a very long continuation line or a further continuation line where the function prototype is very long.)  As an example:

              int tcsetattr(int fd, int optional_actions,
                            const struct termios *termios_p);

       2. But,  where multiple functions in the SYNOPSIS require continuation lines, and the function names have different lengths, then align all continuation lines to
          start in the same column.  This provides a nicer rendering in PDF output (because the SYNOPSIS uses a variable width font where spaces  render  narrower  than
          most characters).  As an example:

              int getopt(int argc, char * const argv[],
                         const char *optstring);
              int getopt_long(int argc, char * const argv[],
                         const char *optstring,
                         const struct option *longopts, int *longindex);

   RETURN VALUE
       The  preferred wording to describe how errno is set is "errno is set to indicate the error" or similar.  This wording is consistent with the wording used in both
       POSIX.1 and FreeBSD.

   ATTRIBUTES
       Note the following:

       *  Wrap the table in this section in a .ad l/.ad pair to disable text filling and a .nh/.hy pair to disable hyphenation.

       *  Ensure that the table occupies the full page width through the use of an lbx description for one of the columns (usually the  first  column,  though  in  some
          cases the last column if it contains a lot of text).

       *  Make free use of T{/T} macro pairs to allow table cells to be broken over multiple lines (also bearing in mind that pages may sometimes be rendered to a width
          of less than 80 columns).

       For examples of all of the above, see the source code of various pages.

STYLE GUIDE
       The following subsections describe the preferred style for the man-pages project.  For details not covered below, the Chicago Manual of Style is usually  a  good
       source; try also grepping for preexisting usage in the project source tree.

   Use of gender-neutral language
       As  far  as  possible, use gender-neutral language in the text of man pages.  Use of "they" ("them", "themself", "their") as a gender-neutral singular pronoun is
       acceptable.

   Formatting conventions for manual pages describing commands
       For manual pages that describe a command (typically in Sections 1 and 8), the arguments are always specified using italics, even in the SYNOPSIS section.

       The name of the command, and its options, should always be formatted in bold.

   Formatting conventions for manual pages describing functions
       For manual pages that describe functions (typically in Sections 2 and 3), the arguments are always specified using italics, even in the SYNOPSIS  section,  where
       the rest of the function is specified in bold:

           int myfunction(int argc, char **argv);

       Variable names should, like argument names, be specified in italics.

       Any  reference  to  the subject of the current manual page should be written with the name in bold followed by a pair of parentheses in Roman (normal) font.  For
       example, in the fcntl(2) man page, references to the subject of the page would be written as: fcntl().  The preferred way to write this in the source file is:

           .BR fcntl ()

       (Using this format, rather than the use of "\fB...\fP()" makes it easier to write tools that parse man page source files.)

   Use semantic newlines
       In the source of a manual page, new sentences should be started on new lines, and long sentences should be split into lines at clause breaks (commas, semicolons,
       colons,  and  so on).  This convention, sometimes known as "semantic newlines", makes it easier to see the effect of patches, which often operate at the level of
       individual sentences or sentence clauses.

   Formatting conventions (general)
       Paragraphs should be separated by suitable markers (usually either .PP or .IP).  Do not separate paragraphs using blank lines, as this results in poor  rendering
       in some output formats (such as PostScript and PDF).

       Filenames (whether pathnames, or references to header files) are always in italics (e.g., <stdio.h>), except in the SYNOPSIS section, where included files are in
       bold (e.g., #include <stdio.h>).  When referring to a standard header file include, specify the header file surrounded by angle brackets,  in  the  usual  C  way
       (e.g., <stdio.h>).

       Special macros, which are usually in uppercase, are in bold (e.g., MAXINT).  Exception: don't boldface NULL.

       When enumerating a list of error codes, the codes are in bold (this list usually uses the .TP macro).

       Complete commands should, if long, be written as an indented line on their own, with a blank line before and after the command, for example

           man 7 man-pages

       If  the  command  is short, then it can be included inline in the text, in italic format, for example, man 7 man-pages.  In this case, it may be worth using non‐
       breaking spaces ("\ ") at suitable places in the command.  Command options should be written in italics (e.g., -l).

       Expressions, if not written on a separate indented line, should be specified in italics.  Again, the use of nonbreaking spaces may be appropriate if the  expres‐
       sion is inlined with normal text.

       When showing example shell sessions, user input should be formatted in bold, for example

           $ date
           Thu Jul  7 13:01:27 CEST 2016

       Any  reference  to another man page should be written with the name in bold, always followed by the section number, formatted in Roman (normal) font, without any
       separating spaces (e.g., intro(2)).  The preferred way to write this in the source file is:

           .BR intro (2)

       (Including the section number in cross references lets tools like man2html(1) create properly hyperlinked pages.)

       Control characters should be written in bold face, with no quotes; for example, ^X.

   Spelling
       Starting with release 2.59, man-pages follows American spelling conventions (previously, there was a random mix of British and American spellings); please  write
       all new pages and patches according to these conventions.

       Aside from the well-known spelling differences, there are a few other subtleties to watch for:

       *  American English tends to use the forms "backward", "upward", "toward", and so on rather than the British forms "backwards", "upwards", "towards", and so on.

       *  Opinions are divided on "acknowledgement" vs "acknowledgment".  The latter is predominant, but not universal usage in American English.  POSIX and the BSD li‐
          cense use the former spelling.  In the Linux man-pages project, we use "acknowledgement".

   BSD version numbers
       The classical scheme for writing BSD version numbers is x.yBSD, where x.y is the version number (e.g., 4.2BSD).  Avoid forms such as BSD 4.3.

   Capitalization
       In subsection ("SS") headings, capitalize the first word in the heading, but otherwise use lowercase, except where English usage (e.g., proper nouns) or program‐
       ming language requirements (e.g., identifier names) dictate otherwise.  For example:

           .SS Unicode under Linux

   Indentation of structure definitions, shell session logs, and so on
       When structure definitions, shell session logs, and so on are included in running text, indent them by 4 spaces (i.e., a block enclosed by .in +4n and .in), for‐
       mat them using the .EX and EE macros, and surround them with suitable paragraph markers (either .PP or .IP).  For example:

               .PP
               .in +4n
               .EX
               int
               main(int argc, char *argv[])
               {
                   return 0;
               }
               .EE
               .in
               .PP

   Preferred terms
       The following table lists some preferred terms to use in man pages, mainly to ensure consistency across pages.

       Term                 Avoid using                     Notes
       ───────────────────────────────────────────────────────────────────────────────────────
       bit mask             bitmask
       built-in             builtin
       Epoch                epoch                           For the UNIX Epoch (00:00:00, 1
                                                            Jan 1970 UTC)
       filename             file name
       filesystem           file system
       hostname             host name
       inode                i-node
       lowercase            lower case, lower-case
       nonzero              non-zero
       pathname             path name
       pseudoterminal       pseudo-terminal
       privileged port      reserved port, system port
       real-time            realtime, real time
       run time             runtime
       saved set-group-ID   saved group ID, saved set-GID
       saved set-user-ID    saved user ID, saved set-UID
       set-group-ID         set-GID, setgid
       set-user-ID          set-UID, setuid
       superuser            super user, super-user
       superblock           super block, super-block
       timestamp            time stamp
       timezone             time zone
       uppercase            upper case, upper-case
       usable               useable
       user space           userspace
       username             user name
       x86-64               x86_64                          Except if referring to result of
                                                            "uname -m" or similar
       zeros                zeroes

       See also the discussion Hyphenation of attributive compounds below.

   Terms to avoid
       The following table lists some terms to avoid using in man pages, along with some suggested alternatives, mainly to ensure consistency across pages.

       Avoid             Use instead             Notes
       ───────────────────────────────────────────────────────────────────────────────────

       32bit             32-bit                  same for 8-bit, 16-bit, etc.
       current process   calling process         A common mistake made by kernel program‐
                                                 mers when writing man pages
       manpage           man page, manual page
       minus infinity    negative infinity
       non-root          unprivileged user
       non-superuser     unprivileged user
       nonprivileged     unprivileged
       OS                operating system
       plus infinity     positive infinity
       pty               pseudoterminal
       tty               terminal
       Unices            UNIX systems
       Unixes            UNIX systems

   Trademarks
       Use the correct spelling and case for trademarks.  The following is a list of the correct spellings of various relevant trademarks that are sometimes misspelled:

            DG/UX
            HP-UX
            UNIX
            UnixWare

   NULL, NUL, null pointer, and null byte
       A  null  pointer  is  a pointer that points to nothing, and is normally indicated by the constant NULL.  On the other hand, NUL is the null byte, a byte with the
       value 0, represented in C via the character constant '\0'.

       The preferred term for the pointer is "null pointer" or simply "NULL"; avoid writing "NULL pointer".

       The preferred term for the byte is "null byte".  Avoid writing "NUL", since it is too easily confused with "NULL".  Avoid also the terms "zero  byte"  and  "null
       character".  The byte that terminates a C string should be described as "the terminating null byte"; strings may be described as "null-terminated", but avoid the
       use of "NUL-terminated".

   Hyperlinks
       For hyperlinks, use the .UR/.UE macro pair (see groff_man(7)).  This produces proper hyperlinks that can be used in a web browser, when rendering  a  page  with,
       say:

            BROWSER=firefox man -H pagename

   Use of e.g., i.e., etc., a.k.a., and similar
       In  general,  the  use of abbreviations such as "e.g.", "i.e.", "etc.", "cf.", and "a.k.a." should be avoided, in favor of suitable full wordings ("for example",
       "that is", "and so on", "compare to", "also known as").

       The only place where such abbreviations may be acceptable is in short parenthetical asides (e.g., like this one).

       Always include periods in such abbreviations, as shown here.  In addition, "e.g." and "i.e." should always be followed by a comma.

   Em-dashes
       The way to write an em-dashβ€”the glyph that appears at either end of this subphraseβ€”in *roff is with the macro "\(em".  (On an ASCII terminal,  an  em-dash  typi‐
       cally renders as two hyphens, but in other typographical contexts it renders as a long dash.)  Em-dashes should be written without surrounding spaces.

   Hyphenation of attributive compounds
       Compound terms should be hyphenated when used attributively (i.e., to qualify a following noun). Some examples:

           32-bit value
           command-line argument
           floating-point number
           run-time check
           user-space function
           wide-character string

   Hyphenation with multi, non, pre, re, sub, and so on
       The  general  tendency in modern English is not to hyphenate after prefixes such as "multi", "non", "pre", "re", "sub", and so on.  Manual pages should generally
       follow this rule when these prefixes are used in natural English constructions with simple suffixes.  The following list gives some  examples  of  the  preferred
       forms:

           interprocess
           multithreaded
           multiprocess
           nonblocking
           nondefault
           nonempty
           noninteractive
           nonnegative
           nonportable
           nonzero
           preallocated
           precreate
           prerecorded
           reestablished
           reinitialize
           rearm
           reread
           subcomponent
           subdirectory
           subsystem

       Hyphens should be retained when the prefixes are used in nonstandard English words, with trademarks, proper nouns, acronyms, or compound terms.  Some examples:

           non-ASCII
           non-English
           non-NULL
           non-real-time

       Finally, note that "re-create" and "recreate" are two different verbs, and the former is probably what you want.

   Generating optimal glyphs
       Where a real minus character is required (e.g., for numbers such as -1, for man page cross references such as utf-8(7), or when writing options that have a lead‐
       ing dash, such as in ls -l), use the following form in the man page source:

           \-

       This guideline applies also to code examples.

       The use of real minus signs serves the following purposes:

       *  To provide better renderings on various targets other than ASCII terminals, notably in PDF and on Unicode/UTF-8-capable terminals.

       *  To generate glyphs that when copied from rendered pages will produce real minus signs when pasted into a terminal.

       To produce unslanted single quotes that render well in ASCII, UTF-8, and PDF, use "\(aq" ("apostrophe quote"); for example

           \(aqC\(aq

       where C is the quoted character.  This guideline applies also to character constants used in code examples.

       Where a proper caret (^) that renders well in both a terminal and PDF is required, use "\(ha".  This is especially necessary in code samples,  to  get  a  nicely
       rendered caret when rendering to PDF.

       Using  a  naked  "~"  character  results in a poor rendering in PDF.  Instead use "\(ti".  This is especially necessary in code samples, to get a nicely rendered
       tilde when rendering to PDF.

   Example programs and shell sessions
       Manual pages may include example programs demonstrating how to use a system call or library function.  However, note the following:

       *  Example programs should be written in C.

       *  An example program is necessary and useful only if it demonstrates something beyond what can easily be provided in a textual description of the interface.  An
          example program that does nothing other than call an interface usually serves little purpose.

       *  Example programs should ideally be short (e.g., a good example can often be provided in less than 100 lines of code), though in some cases longer programs may
          be necessary to properly illustrate the use of an API.

       *  Expressive code is appreciated.

       *  Comments should included where helpful.  Complete sentences in free-standing comments should be terminated by a period.  Periods should generally  be  omitted
          in  "tag"  comments (i.e., comments that are placed on the same line of code); such comments are in any case typically brief phrases rather than complete sen‐
          tences.

       *  Example programs should do error checking after system calls and library function calls.

       *  Example programs should be complete, and compile without warnings when compiled with cc -Wall.

       *  Where possible and appropriate, example programs should allow experimentation, by varying their behavior based on inputs (ideally from command-line arguments,
          or alternatively, via input read by the program).

       *  Example  programs  should  be laid out according to Kernighan and Ritchie style, with 4-space indents.  (Avoid the use of TAB characters in source code!)  The
          following command can be used to format your source code to something close to the preferred style:

              indent -npro -kr -i4 -ts4 -sob -l72 -ss -nut -psl prog.c

       *  For consistency, all example programs should terminate using either of:

               exit(EXIT_SUCCESS);
               exit(EXIT_FAILURE);

          Avoid using the following forms to terminate a program:

              exit(0);
              exit(1);
              return n;

       *  If there is extensive explanatory text before the program source code, mark off the source code with a subsection heading Program source, as in:

              .SS Program source

          Always do this if the explanatory text includes a shell session log.

       If you include a shell session log demonstrating the use of a program or other system feature:

       *  Place the session log above the source code listing

       *  Indent the session log by four spaces.

       *  Boldface the user input text, to distinguish it from output produced by the system.

       For some examples of what example programs should look like, see wait(2) and pipe(2).

EXAMPLES
       For canonical examples of how man pages in the man-pages package should look, see pipe(2) and fcntl(2).

SEE ALSO
       man(1), man2html(1), attributes(7), groff(7), groff_man(7), man(7), mdoc(7)

Linux                                                                          2021-03-22                                                                   MAN-PAGES(7)