PERLPODSTYLE(1) Perl Programmers Reference Guide PERLPODSTYLE(1)NAMEperlpodstyle - Perl POD style guide
DESCRIPTION
These are general guidelines for how to write POD documentation for
Perl scripts and modules, based on general guidelines for writing good
Unix man pages. All of these guidelines are, of course, optional, but
following them will make your documentation more consistent with other
documentation on the system.
Here are some simple guidelines for markup; see perlpod for details.
bold (B<>)
NOTE: Use extremely rarely. Do not use bold for emphasis; that's
what italics are for. Restrict bold for notices like NOTE: and
WARNING:. However, program arguments and options--but not their
names!--are written in bold (using B<>) to distinguish the -f
command-line option from the "-f" filetest operator.
italic (I<>)
Use italic to emphasize text, like this. Function names are
traditionally written in italics; if you write a function as
function(), Pod::Man will take care of this for you. Names of
programs, including the name of the program being documented, are
conventionally written in italics (using I<>) wherever they occur
in normal roman text.
code (C<>)
Literal code should be in C<>. However metasyntactic placeholders
should furthermore be nested in "italics" (actually, oblique) like
C<I<>>. That way C<accept(I<NEWSOCKET>, <GENERICSOCKET>)> renders
as "accept(NEWSOCKET, GENERICSOCKET)".
files (F<>)
Filenames, whether absolute or relative, are specified with the F<>
markup. This will render as italics, but has other semantic
connotations.
References to other man pages should be in the form "manpage(section)"
or ""L<manpage(section)>"", and Pod::Man will automatically format
those appropriately. Both will render as manpage(section). The second
form, with L<>, is used to request that a POD formatter make a link to
the man page if possible. As an exception, one normally omits the
section when referring to module documentation because not all systems
place it in section 3, although that is the default. You may use
"L<Module::Name>" for module references instead, but this is optional
because the translators are supposed to recognize module references in
pod, just as they do variable references like $foo and such.
References to other programs or functions are normally in the form of
man page references so that cross-referencing tools can provide the
user with links and the like. It's possible to overdo this, though, so
be careful not to clutter your documentation with too much markup.
References to other programs that are not given as man page references
should be enclosed in italics via I<>.
Major headers should be set out using a "=head1" directive, and are
historically written in the rather startling ALL UPPER CASE format;
this is not mandatory, but it's strongly recommended so that sections
have consistent naming across different software packages. The
translators are supposed to translate all caps into small caps. Minor
headers may be included using "=head2", and are typically in mixed
case.
The standard sections of a manual page are:
NAME
Mandatory section; should be a comma-separated list of programs or
functions documented by this POD page, such as:
foo, bar - programs to do something
Manual page indexers are often extremely picky about the format of
this section, so don't put anything in it except this line. Every
program or function documented by this POD page should be listed,
separated by a comma and a space. For a Perl module, just give the
module name. A single dash, and only a single dash, should
separate the list of programs or functions from the description.
Do not use any markup such as C<> or I<> anywhere in this line.
Functions should not be qualified with "()" or the like. The
description should ideally fit on a single line, even if a man
program replaces the dash with a few tabs.
SYNOPSIS
A short usage summary for programs and functions. This section is
mandatory for section 3 pages. For Perl module documentation, it's
usually convenient to have the contents of this section be a
verbatim block showing some (brief) examples of typical ways the
module is used.
DESCRIPTION
Extended description and discussion of the program or functions, or
the body of the documentation for man pages that document something
else. If particularly long, it's a good idea to break this up into
subsections "=head2" directives like:
=head2 Normal Usage
=head2 Advanced Features
=head2 Writing Configuration Files
or whatever is appropriate for your documentation.
For a module, this is generally where the documentation of the
interfaces provided by the module goes, usually in the form of a
list with an "=item" for each interface. Depending on how many
interfaces there are, you may want to put that documentation in
separate METHODS, FUNCTIONS, CLASS METHODS, or INSTANCE METHODS
sections instead and save the DESCRIPTION section for an overview.
OPTIONS
Detailed description of each of the command-line options taken by
the program. This should be separate from the description for the
use of parsers like Pod::Usage. This is normally presented as a
list, with each option as a separate "=item". The specific option
string should be enclosed in B<>. Any values that the option takes
should be enclosed in I<>. For example, the section for the option
--section=manext would be introduced with:
=item B<--section>=I<manext>
Synonymous options (like both the short and long forms) are
separated by a comma and a space on the same "=item" line, or
optionally listed as their own item with a reference to the
canonical name. For example, since --section can also be written
as -s, the above would be:
=item B<-s> I<manext>, B<--section>=I<manext>
Writing the short option first is recommended because it's easier
to read. The long option is long enough to draw the eye to it
anyway and the short option can otherwise get lost in visual noise.
RETURN VALUE
What the program or function returns, if successful. This section
can be omitted for programs whose precise exit codes aren't
important, provided they return 0 on success and non-zero on
failure as is standard. It should always be present for functions.
For modules, it may be useful to summarize return values from the
module interface here, or it may be more useful to discuss return
values separately in the documentation of each function or method
the module provides.
ERRORS
Exceptions, error return codes, exit statuses, and errno settings.
Typically used for function or module documentation; program
documentation uses DIAGNOSTICS instead. The general rule of thumb
is that errors printed to "STDOUT" or "STDERR" and intended for the
end user are documented in DIAGNOSTICS while errors passed internal
to the calling program and intended for other programmers are
documented in ERRORS. When documenting a function that sets errno,
a full list of the possible errno values should be given here.
DIAGNOSTICS
All possible messages the program can print out and what they mean.
You may wish to follow the same documentation style as the Perl
documentation; see perldiag(1) for more details (and look at the
POD source as well).
If applicable, please include details on what the user should do to
correct the error; documenting an error as indicating "the input
buffer is too small" without telling the user how to increase the
size of the input buffer (or at least telling them that it isn't
possible) aren't very useful.
EXAMPLES
Give some example uses of the program or function. Don't skimp;
users often find this the most useful part of the documentation.
The examples are generally given as verbatim paragraphs.
Don't just present an example without explaining what it does.
Adding a short paragraph saying what the example will do can
increase the value of the example immensely.
ENVIRONMENT
Environment variables that the program cares about, normally
presented as a list using "=over", "=item", and "=back". For
example:
=over 6
=item HOME
Used to determine the user's home directory. F<.foorc> in this
directory is read for configuration details, if it exists.
=back
Since environment variables are normally in all uppercase, no
additional special formatting is generally needed; they're glaring
enough as it is.
FILES
All files used by the program or function, normally presented as a
list, and what it uses them for. File names should be enclosed in
F<>. It's particularly important to document files that will be
potentially modified.
CAVEATS
Things to take special care with, sometimes called WARNINGS.
BUGS
Things that are broken or just don't work quite right.
RESTRICTIONS
Bugs you don't plan to fix. :-)
NOTES
Miscellaneous commentary.
AUTHOR
Who wrote it (use AUTHORS for multiple people). It's a good idea
to include your current email address (or some email address to
which bug reports should be sent) or some other contact information
so that users have a way of contacting you. Remember that program
documentation tends to roam the wild for far longer than you expect
and pick a contact method that's likely to last.
HISTORY
Programs derived from other sources sometimes have this. Some
people keep a modification log here, but that usually gets long and
is normally better maintained in a separate file.
COPYRIGHT AND LICENSE
For copyright
Copyright YEAR(s) YOUR NAME(s)
(No, (C) is not needed. No, "all rights reserved" is not needed.)
For licensing the easiest way is to use the same licensing as Perl
itself:
This library is free software; you may redistribute it and/or modify
it under the same terms as Perl itself.
This makes it easy for people to use your module with Perl. Note
that this licensing example is neither an endorsement or a
requirement, you are of course free to choose any licensing.
SEE ALSO
Other man pages to check out, like man(1), man(7), makewhatis(8),
or catman(8). Normally a simple list of man pages separated by
commas, or a paragraph giving the name of a reference work. Man
page references, if they use the standard "name(section)" form,
don't have to be enclosed in L<> (although it's recommended), but
other things in this section probably should be when appropriate.
If the package has a mailing list, include a URL or subscription
instructions here.
If the package has a web site, include a URL here.
Documentation of object-oriented libraries or modules may want to use
CONSTRUCTORS and METHODS sections, or CLASS METHODS and INSTANCE
METHODS sections, for detailed documentation of the parts of the
library and save the DESCRIPTION section for an overview. Large
modules with a function interface may want to use FUNCTIONS for similar
reasons. Some people use OVERVIEW to summarize the description if it's
quite long.
Section ordering varies, although NAME must always be the first section
(you'll break some man page systems otherwise), and NAME, SYNOPSIS,
DESCRIPTION, and OPTIONS generally always occur first and in that order
if present. In general, SEE ALSO, AUTHOR, and similar material should
be left for last. Some systems also move WARNINGS and NOTES to last.
The order given above should be reasonable for most purposes.
Some systems use CONFORMING TO to note conformance to relevant
standards and MT-LEVEL to note safeness for use in threaded programs or
signal handlers. These headings are primarily useful when documenting
parts of a C library.
Finally, as a general note, try not to use an excessive amount of
markup. As documented here and in Pod::Man, you can safely leave Perl
variables, module names, function names, man page references, and the
like unadorned by markup, and the POD translators will figure it all
out for you. This makes it much easier to later edit the
documentation. Note that many existing translators will do the wrong
thing with email addresses when wrapped in L<>, so don't do that.
You can check whether your documentation looks right by running
% pod2text -o something.pod | less
If you have groff installed, you can get an even better look this way:
% pod2man something.pod | groff -Tps -mandoc > something.ps
Now view the resulting Postscript file to see whether everything checks
out.
SEE ALSO
For additional information that may be more accurate for your specific
system, see either man(5) or man(7) depending on your system manual
section numbering conventions.
This documentation is maintained as part of the podlators distribution.
The current version is always available from its web site at
<http://www.eyrie.org/~eagle/software/podlators/>.
AUTHOR
Russ Allbery <rra@stanford.edu>, with large portions of this
documentation taken from the documentation of the original pod2man
implementation by Larry Wall and Tom Christiansen.
COPYRIGHT AND LICENSE
Copyright 1999, 2000, 2001, 2004, 2006, 2008, 2010 Russ Allbery
<rra@stanford.edu>.
This documentation is free software; you may redistribute it and/or
modify it under the same terms as Perl itself.
perl v5.16.3 2013-03-04 PERLPODSTYLE(1)
