4 Many places in the source tree have extractable documentation in the
5 form of block comments above functions. The components of this system
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
14 - Documentation/DocBook/*.tmpl
16 These are SGML template files, which are normal SGML files with
17 special place-holders for where the extracted documentation should
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
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.
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.
38 - Documentation/DocBook/Makefile
40 This is where C files are associated with SGML templates.
43 How to extract the documentation
44 --------------------------------
46 If you just want to read the ready-made books on the various
47 subsystems (see Documentation/DocBook/*.tmpl), just type 'make
48 psdocs', or 'make pdfdocs', or 'make htmldocs', depending on your
49 preference. If you would rather read a different format, you can type
50 'make sgmldocs' and then use DocBook tools to convert
51 Documentation/DocBook/*.sgml to a format of your choice (for example,
52 'db2html ...' if 'make htmldocs' was not defined).
54 If you want to see man pages instead, you can do this:
57 $ scripts/kernel-doc -man $(find -name '*.c') | split-man.pl /tmp/man
58 $ scripts/kernel-doc -man $(find -name '*.h') | split-man.pl /tmp/man
66 die "where do I put the results?\n";
72 if (/^\.TH \"[^\"]*\" 4 \"([^\"]*)\"/) {
73 if ($state == 1) { close OUT }
75 $fn = "$ARGV[0]/$1.4";
76 print STDERR "Creating $fn\n";
77 open OUT, ">$fn" or die "can't open $fn: $!\n";
79 } elsif ($state != 0) {
87 If you just want to view the documentation for one function in one
88 file, you can do this:
90 $ scripts/kernel-doc -man -function fn file | nroff -man | less
94 $ scripts/kernel-doc -text -function fn file
97 How to add extractable documentation to your source files
98 ---------------------------------------------------------
100 The format of the block comment is like this:
103 * function_name(:)? (- short description)?
104 (* @parameterx: (description of parameter x)?)*
106 * (Description:)? (Description of function)?
107 * (section header: (section description)? )*
110 The short function description cannot be multiline, but the other
111 descriptions can be (and they can contain blank lines). Avoid putting a
112 spurious blank line after the function name, or else the description will
115 All descriptive text is further processed, scanning for the following special
116 patterns, which are highlighted appropriately.
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.
124 Take a look around the source tree for examples.
127 How to make new SGML template files
128 -----------------------------------
130 SGML template files (*.tmpl) are like normal SGML files, except that
131 they can contain escape sequences where extracted documentation should
134 !E<filename> is replaced by the documentation, in <filename>, for
135 functions that are exported using EXPORT_SYMBOL: the function list is
136 collected from files listed in Documentation/DocBook/Makefile.
138 !I<filename> is replaced by the documentation for functions that are
139 _not_ exported using EXPORT_SYMBOL.
141 !D<filename> is used to name additional files to search for functions
142 exported using EXPORT_SYMBOL.
144 !F<filename> <function [functions...]> is replaced by the
145 documentation, in <filename>, for the functions listed.
149 */ <twaugh@redhat.com>