get_boundary_post Only works from a single page

[pathawks]

I was trying to use get_boundary_post in my theme to display a link to the first and last posts, but it does not work from the homepage. Unless called from a single post, get_boundary_post will return NULL.

I can't see any reason for this behavior, or any good way around it.

Has been this way since introduction in [10815] (#8703).

What is the reason for this?

I understand why start_post_rel_link might want to only fire on single posts, but I see no reason to limit the avaliability of get_boundary_post.

On a related note, when there is nothing to return, why does it return NULL rather than FALSE like similar functions?

get_boundary_post from any page