In keeping with `Javadoc` and `Doxygen`, documentation commands are `/` `**…` \(together\) and are ended with `*…/`, but not `/` `*…*` `/`\. Accounts for asterisks at the start of a line, \(Kernel comments,\) or asterisks on both sides, \(ASCII art?\) Documentation appearing at most two lines above `typedef`, `tag` \(`struct`, `enum`, `union`,\) data, and functions, is associated therewith; everything else is automatically inserted into the description\. Multiple documentation on the same command is appended\. Two hard returns is a paragraph\. The big difference is the fixed `@param` notation; now it has to be followed by a braced list, `@param[a, b] Concatenates both.`\.

Supports some `Markdown` commands included in the documentation,

* `\` escapes `_~!@<>[]` and "\`"; "\`" can not be represented in math/code, \(multiple escapes aren't supported\); in paragraph mode, except in ambiguous cases, the only ones that are needed are \\\` and \\\_;
* \_emphasised\_: _emphasised_;
* \`code/math\`: `code/math`;
* start lists with `\*` \(including spaces\) and end with a new paragraph; these are simple, can be anywhere and don't nest;
* `\"` \(and optionally a space\) causes all the line after to be pre\-formatted;
* Escapes included for convenience: `\,` " " non\-breaking thin space, `\O` "Ο" Bachmann–Landau notation, \(but really capital omicron because not many fonts have a shape for code\-point 120030,\) `\Theta` "Θ", `\Omega` "Ω", `\times` "×", `\cdot` "·"\.
* `~` " " non\-breaking space;
* ``: relative URIs must have a slash or a dot to distinguish it from text;
* ``: citation, searches on Google scholar;
* `>`: function reference;
* `>`: struct, union, or enum \(tag\) reference;
* `>`: typedef reference;
* `>`: data reference;
* `[The link text](url)`: link, Markdown doesn't like `{}[]()` in text;
* ``: image, same;
* a local include directive has a documentation comment immediately after that reads only `\include`, it will also be included in the documentation\.

Each\-block\-tags separate the documentation until the next paragraph or until the next each\-block\-tag, and specify a specific documentation structure\. Each\-block\-tags that overlap are concatenated in the file order\. Not all of these are applicable for all segments of text\. These are:

* `@subtitle`: only makes sense for preamble, \(it doesn't matter what case one writes it, but multiple are concatenated using semicolons\);
* `@abstract`: tl;dr appearing first;
* `@param[[, ...]]`: parameters, \(multiple are concatenated using spaces, so this really should be sentence case\);
* `@author` \(commas\);
* `@std`: standard, eg, `@std GNU-C99`, \(semicolons\);
* `@depend`: dependancy, \(semicolons\);
* `@fixme`: something doesn't work as expected, \(spaces\);
* `@return`: normal function return, \(spaces\);
* `@throws[[, ...]]`: exceptional function return; `C` doesn't have native exceptions, so `@throws` means whatever one desires; perhaps a null pointer or false is returned and `errno` is set to `exception1`;
* `@implements`: `C` doesn't have the concept of implements, but we would say that a function having a prototype of `(int (*)(const void *, const void *))` implements `bsearch` and `qsort`;
* `@order`: comments about the run\-time or space;
* and `@allow`, the latter being to allow `static` functions or data in the documentation, which are usually culled\.

If one sets `md` as output, it goes to `GitHub` Markdown that is specifically visible on the `GitHub` page, \(including working anchor links on browsers > 2000\.\) This is not the Markdown supported in the documentation\.

* Standard:
C89
* Dependancies:
[re2c](http://re2c.org/)
* Caveat:
Prototype function parameters ignore `const`\. Documentation on prototypes\. Links to non\-documented code which sometimes doesn't show up, work without error, and create broken links\. A fixme with no args disappears; we should NOT check if the string is empty for these values\. Documentation on global variables is not output\.