linux/Documentation/doc-guide/parse-headers.rst

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parse_headers.pl
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****
NAME
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parse_headers.pl - parse a C file, in order to identify functions, structs,
enums and defines and create cross-references to a Sphinx book.


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SYNOPSIS
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\ **parse_headers.pl**\  [<options>] <C_FILE> <OUT_FILE> [<EXCEPTIONS_FILE>]

Where <options> can be: --debug, --help or --man.


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OPTIONS
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\ **--debug**\

 Put the script in verbose mode, useful for debugging.



\ **--help**\

 Prints a brief help message and exits.



\ **--man**\

 Prints the manual page and exits.




***********
DESCRIPTION
***********


Convert a C header or source file (C_FILE), into a ReStructured Text
included via ..parsed-literal block with cross-references for the
documentation files that describe the API. It accepts an optional
EXCEPTIONS_FILE with describes what elements will be either ignored or
be pointed to a non-default reference.

The output is written at the (OUT_FILE).

It is capable of identifying defines, functions, structs, typedefs,
enums and enum symbols and create cross-references for all of them.
It is also capable of distinguish #define used for specifying a Linux
ioctl.

The EXCEPTIONS_FILE contain two types of statements: \ **ignore**\  or \ **replace**\ .

The syntax for the ignore tag is:


ignore \ **type**\  \ **name**\

The \ **ignore**\  means that it won't generate cross references for a
\ **name**\  symbol of type \ **type**\ .

The syntax for the replace tag is:


replace \ **type**\  \ **name**\  \ **new_value**\

The \ **replace**\  means that it will generate cross references for a
\ **name**\  symbol of type \ **type**\ , but, instead of using the default
replacement rule, it will use \ **new_value**\ .

For both statements, \ **type**\  can be either one of the following:


\ **ioctl**\

 The ignore or replace statement will apply to ioctl definitions like:

 #define	VIDIOC_DBG_S_REGISTER 	 _IOW('V', 79, struct v4l2_dbg_register)



\ **define**\

 The ignore or replace statement will apply to any other #define found
 at C_FILE.



\ **typedef**\

 The ignore or replace statement will apply to typedef statements at C_FILE.



\ **struct**\

 The ignore or replace statement will apply to the name of struct statements
 at C_FILE.



\ **enum**\

 The ignore or replace statement will apply to the name of enum statements
 at C_FILE.



\ **symbol**\

 The ignore or replace statement will apply to the name of enum statements
 at C_FILE.

 For replace statements, \ **new_value**\  will automatically use :c:type:
 references for \ **typedef**\ , \ **enum**\  and \ **struct**\  types. It will use :ref:
 for \ **ioctl**\ , \ **define**\  and \ **symbol**\  types. The type of reference can
 also be explicitly defined at the replace statement.




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EXAMPLES
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ignore define _VIDEODEV2_H


Ignore a #define _VIDEODEV2_H at the C_FILE.

ignore symbol PRIVATE


On a struct like:

enum foo { BAR1, BAR2, PRIVATE };

It won't generate cross-references for \ **PRIVATE**\ .

replace symbol BAR1 :c:type:\`foo\`
replace symbol BAR2 :c:type:\`foo\`


On a struct like:

enum foo { BAR1, BAR2, PRIVATE };

It will make the BAR1 and BAR2 enum symbols to cross reference the foo
symbol at the C domain.


****
BUGS
****


Report bugs to Mauro Carvalho Chehab <mchehab@s-opensource.com>


*********
COPYRIGHT
*********


Copyright (c) 2016 by Mauro Carvalho Chehab <mchehab@s-opensource.com>.

License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>.

This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.