Next / previous posts link – How to disable output?

Using https://wingrep.com found a function called get_previous_posts_link in wp-includes/link-template.php

Well, <?php echo get_previous_posts_link(); ?> in single.php doesn’t seem to display anything.

previous_posts_link and next_posts_link only work in the loop.

For a single.php use Template_Tags/next_post_link …

Like I said, I don’t need output.

Seems to work fine with this code.
$previous_link = get_permalink(get_adjacent_post($in_same_cat = true, $excluded_categories = '', $previous = true)->ID);

For next link, set $previous to false.