@code{chown("link-to-file/",uid,gid)}:
FreeBSD 7.2, Solaris 9.
@item
+Some platforms fail to update the change time when at least one
+argument was not -1, but no ownership changes resulted:
+OpenBSD 4.0.
+@item
When passed an argument of -1, some implementations really set the owner
user/group id of the file to this value, rather than leaving that id of the
file alone.