The get_boundary_post_rel_link() WordPress PHP function retrieves the boundary post relational link, which can be either the start or end post relational link.
Usage
get_boundary_post_rel_link($title = '%title', $in_same_cat = false, $excluded_categories = '', $start = true);
Parameters
$title(string) – Optional. Link title format. Default is ‘%title’.$in_same_cat(bool) – Optional. Whether the link should be in the same category. Default is false.$excluded_categories(string) – Optional. Excluded categories IDs. Default is ”.$start(bool) – Optional. Whether to display the link to the first or last post. Default is true.
More information
See WordPress Developer Resources: get_boundary_post_rel_link
Examples
Get a link to the first post in the same category
// Display the first post link in the same category
echo get_boundary_post_rel_link('%title', true, '', true);
Get a link to the last post, excluding a category
// Display the last post link, excluding category with ID 5
echo get_boundary_post_rel_link('%title', false, '5', false);
Custom link title format
// Display the first post link with a custom link title format
echo get_boundary_post_rel_link('Go to: %title', false, '', true);
Get a link to the last post in the same category
// Display the last post link in the same category
echo get_boundary_post_rel_link('%title', true, '', false);
Exclude multiple categories
// Display the first post link, excluding categories with IDs 3 and 7
echo get_boundary_post_rel_link('%title', false, '3,7', true);