
# Underline

With the flag `MD_FLAG_UNDERLINE`, MD4C sees underscore `_` rather as a mark
denoting an underlined span rather than an ordinary emphasis (or a strong
emphasis).

```````````````````````````````` example
_foo_
.
<p><u>foo</u></p>
````````````````````````````````

In sequences of multiple underscores, each single one translates into an
underline span mark.

```````````````````````````````` example
___foo___
.
<p><u><u><u>foo</u></u></u></p>
````````````````````````````````

Intra-word underscores are not recognized as underline marks:

```````````````````````````````` example
foo_bar_baz
.
<p>foo_bar_baz</p>
````````````````````````````````

Also the parser follows the standard understanding when the underscore can
or cannot open or close a span. Therefore there is no underline in the following
example because no underline can be seen as a closing mark.

```````````````````````````````` example
_foo _bar
.
<p>_foo _bar</p>
````````````````````````````````
