["packet steve" <packetsteve@xxxxxxxxxxx>]

Yes, I was confused.  The udp.port1/udp.port2 does most of what I wanted.  I 
mixed up the "udp.port" in prefs_register_uint_preference with the 
"udp.port" that would be used in dissector_add/dissector_delete.  Using 
udp.port1, udp.port2 works.

The prefs_register_uint_list_preference would be cleaner for protocols that 
use dynamic ports.

Thanks.


> From: Guy Harris <guy@xxxxxxxxxx>
> To: packet steve <packetsteve@xxxxxxxxxxx>
> CC: ethereal-dev@xxxxxxxxxxxx
> Subject: Re: [Ethereal-dev] Multiple ports used in preferences.
> Date: Tue, 16 Apr 2002 18:36:33 -0700
>
> On Tue, Apr 16, 2002 at 09:21:35PM -0400, packet steve wrote:
> > I need to allow a protocol to be called from multiple, but varying, UDP
> > ports.
> > The obvious technique
> > prefs_register_uint_preference(my_module, "udp.port", " UDP Port#1",
> > ...          10, &global_my_udp_port1)
> > prefs_register_uint_preference(my_module, "udp.port", " UDP Port#2",
> > ...          10, &global_my_udp_port2)
> >
> > doesn't seem to work:
> >
> > ** ERROR **: file prefs.c: line 274 (register_preference): assertion 
> failed:
> > (find_preference(module, name) == NULL)
> > aborting...
> >
> > Am I trying to do something unreasonable?
>
> Well, to some extent, yes, you are - it is unreasonable to register two
> different preferences with the *same* name, which is why Ethereal
> explicitly checks for that and aborts; people have supplied code to do
> that in the past, and there's somewhat gross code that attempts to work
> around that so that old bogus preference files can be read and dealt
> with not *too* painfully.
>
> The reason why this is unreasonable is that there's no way for Ethereal
> or Tethereal to know to which of those two options "foo.udp.port", as
> used in a "-o" command-line option or in a preferences file, refers.
> For example, if the preference file had
>
> 	foo.udp.port: 666
> 	foo.udp.port: 777
>
> it'd probably set "global_my_udp_port1" to 666 and then to 777 as it's
> reading the file (as I think that'd be the first "udp.port" it found
> when searching the list of preferences for "foo"; if not, it'd set
> "global_my_udp_port2", instead), and not set "global_my_udp_port2" at
> all.
>
> It is not unreasonable to have multiple ports, but it *is* unreasonable
> to implement them in the fashion you show above.
>
> An alternative would be to add a new type of preference, which would be
> a "list of integers" preference.  You might have
>
> 	void prefs_register_uint_list_preference(module_t *module, const
> 	    char *name, const char *title, const char *description,
> 	    guint base, guint *var_nvalues, guint **values);
>
> which would take, as its last two arguments, a pointer to a "guint"
> variable in which the number of integers would be stored, and a pointer
> to a "guint *" in which a pointer to the first element of an array of
> unsigned integers would be stored.
>
> The list would be represented, in text form, as a comma-separated list,
> so that's what you'd put in the preferences dialog box, in the
> preferences file, or in a "-o" option.
>
> > I could work around a
> > limitation by having multiple preference panels.  This seems ugly.
>
> Presumably by "multiple preference panels" you mean "multiple preference
> items", as in
>
> 	prefs_register_uint_preference(my_module, "udp.port1", " UDP Port#1",
> 	     ...          10, &global_my_udp_port1)
> 	prefs_register_uint_preference(my_module, "udp.port2", " UDP Port#2",
> 	     ...          10, &global_my_udp_port2)
>
> so that the preference dialog would have
>
> 	UDP Port#1:   [                                            ]
> 	UDP Port#2:   [                                            ]
>
> I.e., there would be only one pane for the protocol, not multiple panes,
> but there'd be two text fields.
>
> If so, what was the GUI you would have expected from
>
> 	prefs_register_uint_preference(my_module, "udp.port", " UDP Port#1",
> 	     ...          10, &global_my_udp_port1)
> 	prefs_register_uint_preference(my_module, "udp.port", " UDP Port#2",
> 	     ...          10, &global_my_udp_port2)
>
> How would the user have modified both ports from the pane for your
> protocol?  There'd have to have been more than one text field, but
> that'd look the same.




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