get_post_comments_feed_link( int $post_id = 0, string $feed = '' ): 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

$post_idintoptional

Post ID. Default is the ID of the global $post.Default: 0

$feedstringoptional

Feed type. Possible values include 'rss2', 'atom'.
Default is the value of get_default_feed().Default: ''

Return value

string

The permalink for the comments feed for the given post on success, empty string on failure.

Performance profile

How much work a call to get_post_comments_feed_link() 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

16–71

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 129.

Plugin surface

1 hook

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

Called by

5

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

What it touches

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

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 · 32 distinct outcomes

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

Hooks and filters fired · 1

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

1. 1
   apply_filters( post_comments_feed_link )filterline 820 (+75 into the body)

   Filters the post comments feed permalink.

Uses · 12

• absint()Converts a value to non-negative integer.
• get_the_ID()Retrieves the ID of the current item in the WordPress Loop.
• get_default_feed()Retrieves the default feed.
• get_post()Retrieves post data given a post ID or post object.
• get_option()Retrieves an option value based on an option name.
• _get_page_link()Retrieves the page permalink.
• get_permalink()Retrieves the full permalink for the current post or post ID.
• home_url()Retrieves the URL for the current site where the front end is accessible.
• add_query_arg()Retrieves a modified URL query string.
• trailingslashit()Appends a trailing slash.
• user_trailingslashit()Retrieves a trailing-slashed string if the site is set for adding trailing slashes.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 5

• comments_rss()Return link to the post RSS feed.
• feed_links_extra()Displays the links to the extra feeds such as category feeds.
• post_comments_feed_link()Displays the comment feed link for a post.
• redirect_canonical()Redirects incoming links to the proper URL based on the site url.
• redirect_guess_404_permalink()Attempts to guess the correct URL for a 404 request based on query vars.

Source code

View on Trac ↗View on GitHub ↗

745function get_post_comments_feed_link( $post_id = 0, $feed = '' ) {746	$post_id = absint( $post_id );747 748	if ( ! $post_id ) {749		$post_id = get_the_ID();750	}751 752	if ( empty( $feed ) ) {753		$feed = get_default_feed();754	}755 756	$post = get_post( $post_id );757 758	// Bail out if the post does not exist.759	if ( ! $post instanceof WP_Post ) {760		return '';761	}762 763	$unattached = 'attachment' === $post->post_type && 0 === (int) $post->post_parent;764 765	if ( get_option( 'permalink_structure' ) ) {766		if ( 'page' === get_option( 'show_on_front' ) && (int) get_option( 'page_on_front' ) === $post_id ) {767			$url = _get_page_link( $post_id );768		} else {769			$url = get_permalink( $post_id );770		}771 772		if ( $unattached ) {773			$url = home_url( '/feed/' );774			if ( get_default_feed() !== $feed ) {775				$url .= "$feed/";776			}777			$url = add_query_arg( 'attachment_id', $post_id, $url );778		} else {779			$url = trailingslashit( $url ) . 'feed';780			if ( get_default_feed() !== $feed ) {781				$url .= "/$feed";782			}783			$url = user_trailingslashit( $url, 'single_feed' );784		}785	} else {786		if ( $unattached ) {787			$url = add_query_arg(788				array(789					'feed'          => $feed,790					'attachment_id' => $post_id,791				),792				home_url( '/' )793			);794		} elseif ( 'page' === $post->post_type ) {795			$url = add_query_arg(796				array(797					'feed'    => $feed,798					'page_id' => $post_id,799				),800				home_url( '/' )801			);802		} else {803			$url = add_query_arg(804				array(805					'feed' => $feed,806					'p'    => $post_id,807				),808				home_url( '/' )809			);810		}811	}812 813	/**814	 * Filters the post comments feed permalink.815	 *816	 * @since 1.5.1817	 *818	 * @param string $url Post comments feed permalink.819	 */820	return apply_filters( 'post_comments_feed_link', $url );821}

Changelog

Introduced in 2.2.0. 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 6.7.7 tag, from src/wp-includes/link-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

Something wrong on this page? Report it and it gets fixed in the next regeneration.