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function is not described

wp_add_trashed_suffix_to_post_name_for_trashed_posts() WP 4.5.0

Adds a suffix if any trashed posts have a given slug.

Store its desired (i.e. current) slug so it can try to reclaim it if the post is untrashed.

For internal use.

No Hooks.

Return

Nothing (null).

Usage

wp_add_trashed_suffix_to_post_name_for_trashed_posts( $post_name, $post_ID );
$post_name(string) (required)
Slug.
$post_ID(string)
Post ID that should be ignored.
Default: 0

Code of wp add trashed suffix to post name for trashed posts: wp-includes/post.php VER 5.0.3

<?php
function wp_add_trashed_suffix_to_post_name_for_trashed_posts( $post_name, $post_ID = 0 ) {
	$trashed_posts_with_desired_slug = get_posts( array(
		'name' => $post_name,
		'post_status' => 'trash',
		'post_type' => 'any',
		'nopaging' => true,
		'post__not_in' => array( $post_ID )
	) );

	if ( ! empty( $trashed_posts_with_desired_slug ) ) {
		foreach ( $trashed_posts_with_desired_slug as $_post ) {
			wp_add_trashed_suffix_to_post_name_for_post( $_post );
		}
	}
}