As implied by Are URLs to doxygen pages permanent, URL in doxygen are not permanent.
So, how do you hyperlink deep content (ex: a specific function) in doxygen from an external site/doc ?
(For now, hinting the user on using the search box from the home seems an adequate workaround)
Links are based on the function signature, so they persistent indeed (under the condition that
SHORT_NAMESis set toNO, which is the default).