jack_port_get_connections() ignores owned port status

[falkTX]

According to the JACK API, jack_port_get_connections() should only return connections if we're the owner of the port. See: http://jackaudio.org/files/docs/html/group__PortFunctions.html#ga4e1bd29a68acb4fb45f75931de0d36b2 (2nd note)

But in JACK2, using that function always returns non-NULL for all ports (like system:* ones). JACK2 should verify if we own the port being passed in the function parameter, and return NULL if not.

related code is at https://github.com/jackaudio/jack2/blob/master/common/JackAPI.cpp#L1097

[sletz]

Le 25 déc. 2013 à 22:55, falkTX notifications@github.com a écrit :

According to the JACK API, jack_port_get_connections() should only return connections if we're the owner of the port. See: http://jackaudio.org/files/docs/html/group__PortFunctions.html#ga4e1bd29a68acb4fb45f75931de0d36b2 (2nd note)

But in JACK2, using that function always returns non-NULL for all ports (like system:* ones). JACK2 should verify if we own the port being passed in the function parameter, and return NULL if not.

related code is at https://github.com/jackaudio/jack2/blob/master/common/JackAPI.cpp#L1097

— Reply to this email directly or view it on GitHub.

How do we know that "we own the port" since jack_port_get_connections does not have a jack_client_t* parameter ?

Stéphane

[falkTX]

afaik "owning the port" refers to the calling process. not sure how jack1 does it, I'll check the code.

EDIT: relevant code is here: https://github.com/jackaudio/jack1/blob/master/libjack/port.c#L345

[sletz]

On Mon, Jan 6, 2014 at 4:21 AM, Stéphane Letz letz@grame.fr wrote:

Le 25 déc. 2013 à 22:55, falkTX notifications@github.com a écrit :

According to the JACK API, jack_port_get_connections() should only return connections if we're the owner of the port. See:

The text reads:

2) You need not be the owner of the port to get information about its connections.

The third word is "NOT"

[falkTX]

Yes, correct.

the _jack_port_get_allconnections function has that info, but perhaps you're missing the context. quoting from http://jackaudio.org/files/docs/html/group__PortFunctions.html#ga4e1bd29a68acb4fb45f75931de0d36b2

const char** jack_port_get_all_connections(....)

This differs from jack_port_get_connections() in two important respects:
2) You need not be the owner of the port to get information about its connections.

This implies that for _jack_port_getconnections() we need to be the owner of the port, while for _jack_port_get_allconnections() we do not.

I was bitten by this because I was using only jack2 and _jack_port_getconnections(). When I tested my app in JACK1 no system connections were shown in my patchbay.

[pauldavisthefirst]

I think that the implication that you read here was not intended, and simply reflects the fact that jack_port_get_connections() requires a jack_port_t* which is hard to have unless you are the owner.

[falkTX]

not sure if this qualifies as "hard"... jack_port_t* port = jack_port_by_name(client, "system:playback_1");

anyway, because JACK1 implementation does returns NULL for ports that are not part of the current process client, my app was not working properly there. JACK2 did return all connections, so I never noticed the issue until I had to use JACK1.

having JACK1 and JACK2 behaving consistently is my target here. thanks

[pauldavisthefirst]

This has been discussed before. JACK2's internal port implementation is wildly different from JACK1's (and weaker, IMO, because of its fixed size design). It allows jack_port_by_name() to work for ports of other clients.

It would have been great if the original "spec" for the function had made the behaviour well-defined, but it didn't.

On Mon, Jan 6, 2014 at 11:22 AM, Filipe Coelho notifications@github.comwrote:

not sure if this qualifies as "hard"... jack_port_t* port = jack_port_by_name(client, "system:playback_1");

anyway, because JACK1 implementation does returns NULL for ports that are not part of the current process client, my app was not working properly there. JACK2 did return all connections, so I never noticed the issue until I had to use JACK1.

having JACK1 and JACK2 behaving consistently is my target here. thanks

— Reply to this email directly or view it on GitHubhttps://github.com/jackaudio/jack2/issues/47#issuecomment-31661309 .

[sletz]

blockquote {padding-left: 1ex; margin: 0px 0px 0px 0.8ex; border-left: #cccccc 1px solid;} p {margin: 0px;padding: 0px;} Dnia Poniedziałek, 6 Stycznia 2014 14:54 Paul Davis paul@linuxaudiosystems.com napisał(a)

On Mon, Jan 6, 2014 at 4:21 AM, Stéphane Letz letz@grame.fr wrote: Le 25 déc. 2013 ŕ 22:55, falkTX notifications@github.com a écrit : > According to the JACK API, jack_port_get_connections() should only return connections if we're the owner of the port. See:   The text reads:   2) You need not be the owner of the port to get information about its connections. The third word is "NOT"  

But this is about jack_port_get_all_connections, while falkTX ask for  jack_port_get_connections.   ;-)

[sletz]

On 6 January 2014 19:33, Pawel xj@wp.pl wrote:

But this is about jack_port_get_all_connections, while falkTX ask for jack_port_get_connections.

Yes, I noticed that, and just because jack_port_get_all_connections says -

"You need not be the owner of the port to get information about its connections."

I wouldn't necessarily read that as jack_port_get_connections meaning -

You need to be the owner of the port to get information about its connections.

I assumed that meant that jack_port_get_connections doesn't guarantee to provide this information for ports you don't own, not that it mustn't.

Best wishes,

Neil

Neil C Smith Artist : Technologist : Adviser http://neilcsmith.net

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