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Diffstat (limited to 'Documentation/doc-guide/kernel-doc.rst')
| -rw-r--r-- | Documentation/doc-guide/kernel-doc.rst | 362 |
1 files changed, 259 insertions, 103 deletions
diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst index b24854b5d6be..722d4525f7cf 100644 --- a/Documentation/doc-guide/kernel-doc.rst +++ b/Documentation/doc-guide/kernel-doc.rst @@ -65,7 +65,7 @@ Without options, the kernel-doc directive includes all documentation comments from the source file. The kernel-doc extension is included in the kernel source tree, at -``Documentation/sphinx/kernel-doc.py``. Internally, it uses the +``Documentation/sphinx/kerneldoc.py``. Internally, it uses the ``scripts/kernel-doc`` script to extract the documentation comments from the source. @@ -112,16 +112,17 @@ Example kernel-doc function comment:: /** * foobar() - Brief description of foobar. - * @arg: Description of argument of foobar. + * @argument1: Description of parameter argument1 of foobar. + * @argument2: Description of parameter argument2 of foobar. * * Longer description of foobar. * * Return: Description of return value of foobar. */ - int foobar(int arg) + int foobar(int argument1, char *argument2) The format is similar for documentation for structures, enums, paragraphs, -etc. See the sections below for details. +etc. See the sections below for specific details of each type. The kernel-doc structure is extracted from the comments, and proper `Sphinx C Domain`_ function and type descriptions with anchors are generated for them. The @@ -130,6 +131,226 @@ cross-references. See below for details. .. _Sphinx C Domain: http://www.sphinx-doc.org/en/stable/domains.html + +Parameters and member arguments +------------------------------- + +The kernel-doc function comments describe each parameter to the function and +function typedefs or each member of struct/union, in order, with the +``@argument:`` descriptions. For each non-private member argument, one +``@argument`` definition is needed. + +The ``@argument:`` descriptions begin on the very next line following +the opening brief function description line, with no intervening blank +comment lines. + +The ``@argument:`` descriptions may span multiple lines. + +.. note:: + + If the ``@argument`` description has multiple lines, the continuation + of the description should be starting exactly at the same column as + the previous line, e. g.:: + + * @argument: some long description + * that continues on next lines + + or:: + + * @argument: + * some long description + * that continues on next lines + +If a function or typedef parameter argument is ``...`` (e. g. a variable +number of arguments), its description should be listed in kernel-doc +notation as:: + + * @...: description + +Private members +~~~~~~~~~~~~~~~ + +Inside a struct or union description, you can use the ``private:`` and +``public:`` comment tags. Structure fields that are inside a ``private:`` +area are not listed in the generated output documentation. + +The ``private:`` and ``public:`` tags must begin immediately following a +``/*`` comment marker. They may optionally include comments between the +``:`` and the ending ``*/`` marker. + +Example:: + + /** + * struct my_struct - short description + * @a: first member + * @b: second member + * @d: fourth member + * + * Longer description + */ + struct my_struct { + int a; + int b; + /* private: internal use only */ + int c; + /* public: the next one is public */ + int d; + }; + +Function documentation +---------------------- + +The general format of a function and function-like macro kernel-doc comment is:: + + /** + * function_name() - Brief description of function. + * @arg1: Describe the first argument. + * @arg2: Describe the second argument. + * One can provide multiple line descriptions + * for arguments. + * + * A longer description, with more discussion of the function function_name() + * that might be useful to those using or modifying it. Begins with an + * empty comment line, and may include additional embedded empty + * comment lines. + * + * The longer description may have multiple paragraphs. + * + * Return: Describe the return value of foobar. + * + * The return value description can also have multiple paragraphs, and should + * be placed at the end of the comment block. + */ + +The brief description following the function name may span multiple lines, and +ends with an argument description, a blank comment line, or the end of the +comment block. + +Return values +~~~~~~~~~~~~~ + +The return value, if any, should be described in a dedicated section +named ``Return``. + +.. note:: + + #) The multi-line descriptive text you provide does *not* recognize + line breaks, so if you try to format some text nicely, as in:: + + * Return: + * 0 - OK + * -EINVAL - invalid argument + * -ENOMEM - out of memory + + this will all run together and produce:: + + Return: 0 - OK -EINVAL - invalid argument -ENOMEM - out of memory + + So, in order to produce the desired line breaks, you need to use a + ReST list, e. g.:: + + * Return: + * * 0 - OK to runtime suspend the device + * * -EBUSY - Device should not be runtime suspended + + #) If the descriptive text you provide has lines that begin with + some phrase followed by a colon, each of those phrases will be taken + as a new section heading, with probably won't produce the desired + effect. + +Structure, union, and enumeration documentation +----------------------------------------------- + +The general format of a struct, union, and enum kernel-doc comment is:: + + /** + * struct struct_name - Brief description. + * @argument: Description of member member_name. + * + * Description of the structure. + */ + +On the above, ``struct`` is used to mean structs. You can also use ``union`` +and ``enum`` to describe unions and enums. ``argument`` is used +to mean struct and union member names as well as enumerations in an enum. + +The brief description following the structure name may span multiple lines, and +ends with a member description, a blank comment line, or the end of the +comment block. + +The kernel-doc data structure comments describe each member of the structure, +in order, with the member descriptions. + +Nested structs/unions +~~~~~~~~~~~~~~~~~~~~~ + +It is possible to document nested structs unions, like:: + + /** + * struct nested_foobar - a struct with nested unions and structs + * @arg1: - first argument of anonymous union/anonymous struct + * @arg2: - second argument of anonymous union/anonymous struct + * @arg3: - third argument of anonymous union/anonymous struct + * @arg4: - fourth argument of anonymous union/anonymous struct + * @bar.st1.arg1 - first argument of struct st1 on union bar + * @bar.st1.arg2 - second argument of struct st1 on union bar + * @bar.st2.arg1 - first argument of struct st2 on union bar + * @bar.st2.arg2 - second argument of struct st2 on union bar + struct nested_foobar { + /* Anonymous union/struct*/ + union { + struct { + int arg1; + int arg2; + } + struct { + void *arg3; + int arg4; + } + } + union { + struct { + int arg1; + int arg2; + } st1; + struct { + void *arg1; + int arg2; + } st2; + } bar; + }; + +.. note:: + + #) When documenting nested structs or unions, if the struct/union ``foo`` + is named, the argument ``bar`` inside it should be documented as + ``@foo.bar:`` + #) When the nested struct/union is anonymous, the argument ``bar`` on it + should be documented as ``@bar:`` + +Typedef documentation +--------------------- + +The general format of a typedef kernel-doc comment is:: + + /** + * typedef type_name - Brief description. + * + * Description of the type. + */ + +Typedefs with function prototypes can also be documented:: + + /** + * typedef type_name - Brief description. + * @arg1: description of arg1 + * @arg2: description of arg2 + * + * Description of the type. + */ + typedef void (*type_name)(struct v4l2_ctrl *arg1, void *arg2); + + Highlights and cross-references ------------------------------- @@ -201,70 +422,7 @@ cross-references. For further details, please refer to the `Sphinx C Domain`_ documentation. -Function documentation ----------------------- - -The general format of a function and function-like macro kernel-doc comment is:: - - /** - * function_name() - Brief description of function. - * @arg1: Describe the first argument. - * @arg2: Describe the second argument. - * One can provide multiple line descriptions - * for arguments. - * - * A longer description, with more discussion of the function function_name() - * that might be useful to those using or modifying it. Begins with an - * empty comment line, and may include additional embedded empty - * comment lines. - * - * The longer description may have multiple paragraphs. - * - * Return: Describe the return value of foobar. - * - * The return value description can also have multiple paragraphs, and should - * be placed at the end of the comment block. - */ - -The brief description following the function name may span multiple lines, and -ends with an ``@argument:`` description, a blank comment line, or the end of the -comment block. - -The kernel-doc function comments describe each parameter to the function, in -order, with the ``@argument:`` descriptions. The ``@argument:`` descriptions -must begin on the very next line following the opening brief function -description line, with no intervening blank comment lines. The ``@argument:`` -descriptions may span multiple lines. The continuation lines may contain -indentation. If a function parameter is ``...`` (varargs), it should be listed -in kernel-doc notation as: ``@...:``. - -The return value, if any, should be described in a dedicated section at the end -of the comment starting with "Return:". - -Structure, union, and enumeration documentation ------------------------------------------------ - -The general format of a struct, union, and enum kernel-doc comment is:: - - /** - * struct struct_name - Brief description. - * @member_name: Description of member member_name. - * - * Description of the structure. - */ - -Below, "struct" is used to mean structs, unions and enums, and "member" is used -to mean struct and union members as well as enumerations in an enum. - -The brief description following the structure name may span multiple lines, and -ends with a ``@member:`` description, a blank comment line, or the end of the -comment block. -The kernel-doc data structure comments describe each member of the structure, in -order, with the ``@member:`` descriptions. The ``@member:`` descriptions must -begin on the very next line following the opening brief function description -line, with no intervening blank comment lines. The ``@member:`` descriptions may -span multiple lines. The continuation lines may contain indentation. In-line member documentation comments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -294,42 +452,6 @@ on a line of their own, like all other kernel-doc comments:: int foobar; } -Private members -~~~~~~~~~~~~~~~ - -Inside a struct description, you can use the "private:" and "public:" comment -tags. Structure fields that are inside a "private:" area are not listed in the -generated output documentation. The "private:" and "public:" tags must begin -immediately following a ``/*`` comment marker. They may optionally include -comments between the ``:`` and the ending ``*/`` marker. - -Example:: - - /** - * struct my_struct - short description - * @a: first member - * @b: second member - * - * Longer description - */ - struct my_struct { - int a; - int b; - /* private: internal use only */ - int c; - }; - - -Typedef documentation ---------------------- - -The general format of a typedef kernel-doc comment is:: - - /** - * typedef type_name - Brief description. - * - * Description of the type. - */ Overview documentation comments ------------------------------- @@ -376,3 +498,37 @@ file. Data structures visible in kernel include files should also be documented using kernel-doc formatted comments. + +How to use kernel-doc to generate man pages +------------------------------------------- + +If you just want to use kernel-doc to generate man pages you can do this +from the Kernel git tree:: + + $ scripts/kernel-doc -man $(git grep -l '/\*\*' |grep -v Documentation/) | ./split-man.pl /tmp/man + +Using the small ``split-man.pl`` script below:: + + + #!/usr/bin/perl + + if ($#ARGV < 0) { + die "where do I put the results?\n"; + } + + mkdir $ARGV[0],0777; + $state = 0; + while (<STDIN>) { + if (/^\.TH \"[^\"]*\" 9 \"([^\"]*)\"/) { + if ($state == 1) { close OUT } + $state = 1; + $fn = "$ARGV[0]/$1.9"; + print STDERR "Creating $fn\n"; + open OUT, ">$fn" or die "can't open $fn: $!\n"; + print OUT $_; + } elsif ($state != 0) { + print OUT $_; + } + } + + close OUT; |