LXR linux-bk/Documentation/kernel-doc-nano-HOWTO.txt

   1kernel-doc nano-HOWTO
   2=====================
   3
   4Many places in the source tree have extractable documentation in the
   5form of block comments above functions.  The components of this system
   6are:
   7
   8- scripts/kernel-doc
   9
  10  This is a perl script that hunts for the block comments and can mark
  11  them up directly into DocBook, man, text, and HTML. (No, not
  12  texinfo.)
  13
  14- Documentation/DocBook/*.tmpl
  15
  16  These are SGML template files, which are normal SGML files with
  17  special place-holders for where the extracted documentation should
  18  go.
  19
  20- scripts/docproc.c
  21
  22  This is a program for converting SGML template files into SGML
  23  files. When a file is referenced it is searched for symbols
  24  exported (EXPORT_SYMBOL), to be able to distinguish between internal
  25  and external functions.
  26  It invokes kernel-doc, giving it the list of functions that
  27  are to be documented.
  28  Additionally it is used to scan the SGML template files to locate
  29  all the files referenced herein. This is used to generate dependency
  30  information as used by make.
  31
  32- Makefile
  33
  34  The targets 'sgmldocs', 'psdocs', 'pdfdocs', and 'htmldocs' are used
  35  to build DocBook files, PostScript files, PDF files, and html files
  36  in Documentation/DocBook.
  37
  38- Documentation/DocBook/Makefile
  39
  40  This is where C files are associated with SGML templates.
  41
  42
  43How to extract the documentation
  44--------------------------------
  45
  46If you just want to read the ready-made books on the various
  47subsystems (see Documentation/DocBook/*.tmpl), just type 'make
  48psdocs', or 'make pdfdocs', or 'make htmldocs', depending on your 
  49preference.  If you would rather read a different format, you can type 
  50'make sgmldocs' and then use DocBook tools to convert 
  51Documentation/DocBook/*.sgml to a format of your choice (for example, 
  52'db2html ...' if 'make htmldocs' was not defined).
  53
  54If you want to see man pages instead, you can do this:
  55
  56$ cd linux
  57$ scripts/kernel-doc -man $(find -name '*.c') | split-man.pl /tmp/man
  58$ scripts/kernel-doc -man $(find -name '*.h') | split-man.pl /tmp/man
  59
  60Here is split-man.pl:
  61
  62-->
  63#!/usr/bin/perl
  64
  65if ($#ARGV < 0) {
  66   die "where do I put the results?\n";
  67}
  68
  69mkdir $ARGV[0],0777;
  70$state = 0;
  71while (<STDIN>) {
  72    if (/^\.TH \"[^\"]*\" 4 \"([^\"]*)\"/) {
  73        if ($state == 1) { close OUT }
  74        $state = 1;
  75        $fn = "$ARGV[0]/$1.4";
  76        print STDERR "Creating $fn\n";
  77        open OUT, ">$fn" or die "can't open $fn: $!\n";
  78        print OUT $_;
  79    } elsif ($state != 0) {
  80        print OUT $_;
  81    }
  82}
  83
  84close OUT;
  85<--
  86
  87If you just want to view the documentation for one function in one
  88file, you can do this:
  89
  90$ scripts/kernel-doc -man -function fn file | nroff -man | less
  91
  92or this:
  93
  94$ scripts/kernel-doc -text -function fn file
  95
  96
  97How to add extractable documentation to your source files
  98---------------------------------------------------------
  99
 100The format of the block comment is like this:
 101
 102/**
 103 * function_name(:)? (- short description)?
 104(* @parameterx: (description of parameter x)?)*
 105(* a blank line)?
 106 * (Description:)? (Description of function)?
 107 * (section header: (section description)? )*
 108(*)?*/
 109
 110The short function description cannot be multiline, but the other
 111descriptions can be (and they can contain blank lines). Avoid putting a
 112spurious blank line after the function name, or else the description will
 113be repeated!
 114
 115All descriptive text is further processed, scanning for the following special
 116patterns, which are highlighted appropriately.
 117
 118'funcname()' - function
 119'$ENVVAR' - environment variable
 120'&struct_name' - name of a structure (up to two words including 'struct')
 121'@parameter' - name of a parameter
 122'%CONST' - name of a constant.
 123
 124Take a look around the source tree for examples.
 125
 126
 127How to make new SGML template files
 128-----------------------------------
 129
 130SGML template files (*.tmpl) are like normal SGML files, except that
 131they can contain escape sequences where extracted documentation should
 132be inserted.
 133
 134!E<filename> is replaced by the documentation, in <filename>, for
 135functions that are exported using EXPORT_SYMBOL: the function list is
 136collected from files listed in Documentation/DocBook/Makefile.
 137
 138!I<filename> is replaced by the documentation for functions that are
 139_not_ exported using EXPORT_SYMBOL.
 140
 141!D<filename> is used to name additional files to search for functions
 142exported using EXPORT_SYMBOL.
 143
 144!F<filename> <function [functions...]> is replaced by the
 145documentation, in <filename>, for the functions listed.
 146
 147
 148Tim.
 149*/ <twaugh@redhat.com>
 150
 151