comment_class( string|string[] $css_class = '', int|WP_Comment $comment = null, int|WP_Post $post = null, bool $display = true ): void|string

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$css_classstring|string[]optional

One or more classes to add to the class list.
Default empty.Default: ''

$commentint|WP_Commentoptional

Comment ID or WP_Comment object. Default current comment.Default: null

$postint|WP_Postoptional

Post ID or WP_Post object. Default current post.Default: null

$displaybooloptional

Whether to print or return the output.
Default true.Default: true

Return value

void|string

Void if $display argument is true, comment classes if $display is false.

Performance profile

How much work a call to comment_class() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

15–16

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 17.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

10

10 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_post()one call below comment_class()
• hookthird-party callbacksapply_filters()one call below comment_class()

Further down the call graph this can also reach option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost comment_class() can have, taken from its control-flow graph on PHP 8.5.

Uses · 1

• get_comment_class()Returns the classes for the comment div as an array.

Used by · 10

• TwentyNineteen_Walker_Comment::html5_comment()Outputs a comment in the HTML5 format.
• TwentyTwenty_Walker_Comment::html5_comment()Outputs a comment in the HTML5 format.
• Walker_Comment::comment()Outputs a single comment.
• Walker_Comment::html5_comment()Outputs a comment in the HTML5 format.
• Walker_Comment::ping()Outputs a pingback comment.
• _wp_dashboard_recent_comments_row()Outputs a row for the Recent Comments widget.
• block_core_comment_template_render_comments()Function that recursively renders a list of nested comments.
• twentyeleven_comment()Template for comments and pingbacks.
• twentyten_comment()Template for comments and pingbacks.
• twentytwelve_comment()Template for comments and pingbacks.

Source code

View on Trac ↗View on GitHub ↗

493function comment_class( $css_class = '', $comment = null, $post = null, $display = true ) {494	// Separates classes with a single space, collates classes for comment DIV.495	$css_class = 'class="' . implode( ' ', get_comment_class( $css_class, $comment, $post ) ) . '"';496 497	if ( $display ) {498		echo $css_class;499	} else {500		return $css_class;501	}502}

Changelog

Introduced in 2.7.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.9.7 tag, from src/wp-includes/comment-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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