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1===========================2Including uAPI header files3===========================4 5Sometimes, it is useful to include header files and C example codes in6order to describe the userspace API and to generate cross-references7between the code and the documentation. Adding cross-references for8userspace API files has an additional vantage: Sphinx will generate warnings9if a symbol is not found at the documentation. That helps to keep the10uAPI documentation in sync with the Kernel changes.11The :ref:`parse_headers.pl <parse_headers>` provide a way to generate such12cross-references. It has to be called via Makefile, while building the13documentation. Please see ``Documentation/userspace-api/media/Makefile`` for an example14about how to use it inside the Kernel tree.15 16.. _parse_headers:17 18parse_headers.pl19^^^^^^^^^^^^^^^^20 21NAME22****23 24 25parse_headers.pl - parse a C file, in order to identify functions, structs,26enums and defines and create cross-references to a Sphinx book.27 28 29SYNOPSIS30********31 32 33\ **parse_headers.pl**\ [<options>] <C_FILE> <OUT_FILE> [<EXCEPTIONS_FILE>]34 35Where <options> can be: --debug, --help or --usage.36 37 38OPTIONS39*******40 41 42 43\ **--debug**\44 45 Put the script in verbose mode, useful for debugging.46 47 48 49\ **--usage**\50 51 Prints a brief help message and exits.52 53 54 55\ **--help**\56 57 Prints a more detailed help message and exits.58 59 60DESCRIPTION61***********62 63 64Convert a C header or source file (C_FILE), into a reStructuredText65included via ..parsed-literal block with cross-references for the66documentation files that describe the API. It accepts an optional67EXCEPTIONS_FILE with describes what elements will be either ignored or68be pointed to a non-default reference.69 70The output is written at the (OUT_FILE).71 72It is capable of identifying defines, functions, structs, typedefs,73enums and enum symbols and create cross-references for all of them.74It is also capable of distinguish #define used for specifying a Linux75ioctl.76 77The EXCEPTIONS_FILE contain two types of statements: \ **ignore**\ or \ **replace**\ .78 79The syntax for the ignore tag is:80 81 82ignore \ **type**\ \ **name**\83 84The \ **ignore**\ means that it won't generate cross references for a85\ **name**\ symbol of type \ **type**\ .86 87The syntax for the replace tag is:88 89 90replace \ **type**\ \ **name**\ \ **new_value**\91 92The \ **replace**\ means that it will generate cross references for a93\ **name**\ symbol of type \ **type**\ , but, instead of using the default94replacement rule, it will use \ **new_value**\ .95 96For both statements, \ **type**\ can be either one of the following:97 98 99\ **ioctl**\100 101 The ignore or replace statement will apply to ioctl definitions like:102 103 #define VIDIOC_DBG_S_REGISTER _IOW('V', 79, struct v4l2_dbg_register)104 105 106 107\ **define**\108 109 The ignore or replace statement will apply to any other #define found110 at C_FILE.111 112 113 114\ **typedef**\115 116 The ignore or replace statement will apply to typedef statements at C_FILE.117 118 119 120\ **struct**\121 122 The ignore or replace statement will apply to the name of struct statements123 at C_FILE.124 125 126 127\ **enum**\128 129 The ignore or replace statement will apply to the name of enum statements130 at C_FILE.131 132 133 134\ **symbol**\135 136 The ignore or replace statement will apply to the name of enum value137 at C_FILE.138 139 For replace statements, \ **new_value**\ will automatically use :c:type:140 references for \ **typedef**\ , \ **enum**\ and \ **struct**\ types. It will use :ref:141 for \ **ioctl**\ , \ **define**\ and \ **symbol**\ types. The type of reference can142 also be explicitly defined at the replace statement.143 144 145 146EXAMPLES147********148 149 150ignore define _VIDEODEV2_H151 152 153Ignore a #define _VIDEODEV2_H at the C_FILE.154 155ignore symbol PRIVATE156 157 158On a struct like:159 160enum foo { BAR1, BAR2, PRIVATE };161 162It won't generate cross-references for \ **PRIVATE**\ .163 164replace symbol BAR1 :c:type:\`foo\`165replace symbol BAR2 :c:type:\`foo\`166 167 168On a struct like:169 170enum foo { BAR1, BAR2, PRIVATE };171 172It will make the BAR1 and BAR2 enum symbols to cross reference the foo173symbol at the C domain.174 175 176BUGS177****178 179 180Report bugs to Mauro Carvalho Chehab <mchehab@kernel.org>181 182 183COPYRIGHT184*********185 186 187Copyright (c) 2016 by Mauro Carvalho Chehab <mchehab+samsung@kernel.org>.188 189License GPLv2: GNU GPL version 2 <https://gnu.org/licenses/gpl.html>.190 191This is free software: you are free to change and redistribute it.192There is NO WARRANTY, to the extent permitted by law.193