how can I display the doc message from a command?

[Andrea Latina]

Hi all,

from a command defined by

DEFUN_DLD or DEFUN (or DEFCMD, ..)

how can I display its own doc message?

Precisely, I'd like to print the help message when the user passes no
arguments to the command.

Sorry for all these questions, but looking directly inside the octave
source (although quite instructive and inspiring) is somehow time
consuming!

BTW, is there any documentation for octave developers?

So far, I've been only studying the code and looking for examples. It
has been more than enough, but some explicit documentation might be
useful.

Thanks in advance.

Cheers,
Andrea