Hi Cedric,
> My issue is that I define the .HD macro as described in the
> documentation (with \l'6i' or anything for that matter), but it's
> printed just before the footer, rather than just after the header.
>
> .de HD
> .ti 0
> \l'6i'
> ..
Your "text" of the line isn't followed by a break so it isn't output
when HD is being called, at the start of the page with the position set
just after the header, but instead later on when pending output is
flushed.
$ cat hd.tr
.ds LH LH
.ds CH CH
.ds RH RH
.ds LF LF
.ds CF CF
.ds RF RF
.de HD
This is HD.
.br
..
.P1
Hello, good evening, and welcome...
$
$ groff -Tascii -ms hd.tr | uniq -c
3
1 LH CH RH
2
1 This is HD.
1 Hello, good evening, and welcome...
55
1 LF CF RF
2
$
Hope that makes it clear.
Cheers,
Ralph.
