wp_list_comments( string|array $args = array(), WP_Comment[] $comments = null ): void|string

Description

Compatibility

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

Parameters

$argsstring|arrayoptional

Formatting options.Default: array()

• $walkerobjectdefault: null

  Instance of a Walker class to list comments.

• $max_depthintdefault: empty

  The maximum comments depth.

• $stylestringdefault: 'ul'

  The style of list ordering. Accepts 'ul', 'ol', or 'div'. 'div' will result in no additional list markup.

• $callbackcallabledefault: null

  Callback function to use.

• $endcallabledefault: null

  -callback Callback function to use at the end.

• $typestringdefault: 'all'

  Type of comments to list. Accepts 'all', 'comment', 'pingback', 'trackback', 'pings'.

• $pageintdefault: empty

  Page ID to list comments for.

• $per_pageintdefault: empty

  Number of comments to list per page.

• $avatar_sizeintdefault: 32

  Height and width dimensions of the avatar size.

• $reverse_top_levelbooldefault: null

  Ordering of the listed comments. If true, will display newest comments first.

• $reverse_childrenbooldefault: null

  Whether to reverse child comments in the list.

• $formatstringdefault: 'html5' if the theme supports it

  How to format the comments list. Accepts 'html5', 'xhtml'.

• $short_pingbooldefault: false

  Whether to output short pings.

• $echobooldefault: true

  Whether to echo the output or return it.

$commentsWP_Comment[]optional

Array of WP_Comment objects. Default null.Default: null

Return value

void|string

Void if 'echo' argument is true, or no comments to list.
Otherwise, HTML list of comments.

Performance profile

How much work a call to wp_list_comments() 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_comments().

Scaling

Constant

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

Instructions

89–202

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 314.

Plugin surface

1 hook

Third-party callbacks on 'wp_list_comments_args' run inside this call, and their cost is not bounded by anything here.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• hookthird-party callbacksapply_filters()called directly
• optionoption read or writeget_option()called directly
• querycontent queryget_comments()called directly
• cacheobject cachewp_cache_get()one call below wp_list_comments()
• serializeserialisationmaybe_unserialize()one call below wp_list_comments()

Further down the call graph this can also reach transient. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 99 distinct outcomes

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

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 1

One hook fires while wp_list_comments() runs, in this order:

1. 1
   apply_filters( wp_list_comments_args )filterline 2271 (+37 into the body)

   Filters the arguments used in retrieving the comment list.

Uses · 14

• current_theme_supports()Checks a theme's support for a given feature.
• wp_parse_args()Merges user defined arguments into defaults array.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• separate_comments()Separates an array of comments into an array keyed by comment_type.
• get_query_var()Retrieves the value of a query variable in the WP_Query class.
• get_option()Retrieves an option value based on an option name.
• get_the_ID()Retrieves the ID of the current item in the WordPress Loop.
• is_user_logged_in()Determines whether the current visitor is a logged in user.
• get_current_user_id()Gets the current user's ID.
• wp_get_unapproved_comment_author_email()Gets unapproved comment author's email.
• get_comments()Retrieves a list of comments.
• get_comment_pages_count()Calculates the total number of comment pages.

Source code

View on Trac ↗View on GitHub ↗

2234function wp_list_comments( $args = array(), $comments = null ) {2235	global $wp_query, $comment_alt, $comment_depth, $comment_thread_alt, $overridden_cpage, $in_comment_loop;2236 2237	$in_comment_loop = true;2238 2239	$comment_alt        = 0;2240	$comment_thread_alt = 0;2241	$comment_depth      = 1;2242 2243	$defaults = array(2244		'walker'            => null,2245		'max_depth'         => '',2246		'style'             => 'ul',2247		'callback'          => null,2248		'end-callback'      => null,2249		'type'              => 'all',2250		'page'              => '',2251		'per_page'          => '',2252		'avatar_size'       => 32,2253		'reverse_top_level' => null,2254		'reverse_children'  => '',2255		'format'            => current_theme_supports( 'html5', 'comment-list' ) ? 'html5' : 'xhtml',2256		'short_ping'        => false,2257		'echo'              => true,2258	);2259 2260	$parsed_args = wp_parse_args( $args, $defaults );2261 2262	/**2263	 * Filters the arguments used in retrieving the comment list.2264	 *2265	 * @since 4.0.02266	 *2267	 * @see wp_list_comments()2268	 *2269	 * @param array $parsed_args An array of arguments for displaying comments.2270	 */2271	$parsed_args = apply_filters( 'wp_list_comments_args', $parsed_args );2272 2273	// Figure out what comments we'll be looping through ($_comments).2274	if ( null !== $comments ) {2275		$comments = (array) $comments;2276		if ( empty( $comments ) ) {2277			return;2278		}2279		if ( 'all' !== $parsed_args['type'] ) {2280			$comments_by_type = separate_comments( $comments );2281			if ( empty( $comments_by_type[ $parsed_args['type'] ] ) ) {2282				return;2283			}2284			$_comments = $comments_by_type[ $parsed_args['type'] ];2285		} else {2286			$_comments = $comments;2287		}2288	} else {2289		/*2290		 * If 'page' or 'per_page' has been passed, and does not match what's in $wp_query,2291		 * perform a separate comment query and allow Walker_Comment to paginate.2292		 */2293		if ( $parsed_args['page'] || $parsed_args['per_page'] ) {2294			$current_cpage = (int) get_query_var( 'cpage' );2295			if ( ! $current_cpage ) {2296				$current_cpage = 'newest' === get_option( 'default_comments_page' ) ? 1 : $wp_query->max_num_comment_pages;2297			}2298 2299			$current_per_page = (int) get_query_var( 'comments_per_page' );2300			if ( (int) $parsed_args['page'] !== $current_cpage || (int) $parsed_args['per_page'] !== $current_per_page ) {2301				$comment_args = array(2302					'post_id' => get_the_ID(),2303					'orderby' => 'comment_date_gmt',2304					'order'   => 'ASC',2305					'status'  => 'approve',2306				);2307 2308				if ( is_user_logged_in() ) {2309					$comment_args['include_unapproved'] = array( get_current_user_id() );2310				} else {2311					$unapproved_email = wp_get_unapproved_comment_author_email();2312 2313					if ( $unapproved_email ) {

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 7.1.0 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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