WordPress at a glance
filter is not described

comment_link filter-hook . WP 3.6.0

Filters the current comment's permalink.

Usage

add_filter( 'comment_link', 'filter_function_name_295' );
function filter_function_name_295( $comment_permalink ){
	// filter...

	return $comment_permalink;
}
$comment_permalink(string)
The current comment permalink.

Where the hook is called

comment_link()
wp-includes/feed.php 312
echo esc_url( apply_filters( 'comment_link', get_comment_link( $comment ) ) );

Where the hook is used (in WP core)

Does not used.