Hello, I am writing a program that needs jack_get_client_pid (I don't want to use dbus). I first tried to link with libjack, but that function is "not implemented on library side". So, after interpreting some mails in this list I tried linking with libjackserver, which worked. Just to remind: int jack_get_client_pid (const char *name); I do not completely understood what is libjackserver compared to libjack but what I do is that libjackserver defines a larger API and I noticed differences in number/ownage of threads and initialisation of the server. The best way to keep a client's code clean and simple seems to be to link with libjack. If I understood well, libjackserver is supposed to define functions in 'jack/control.h'. What about jack_get_client_pid, then? jack_get_client_pid is declared in 'jack.h'. Moreover, it is declared in 'jack.h' for jack2 (line 225): https://github.com/jackaudio/jack2/blob/master/common/jack/jack.h but it is not in jack1's API: https://github.com/jackaudio/headers/blob/07f1ecf1ce119d861ec631cb4a6a81a1a… I thought about implementing that function in jack2 on library side. I guess that this function is similar to, for instance, jack_get_uuid_for_client_name, even if the process identifier is sort of outside jack. Anyway, jack_get_client_pid seems a bit inconsistent with the rest of the API. Why is it not declared (and renamed): int jack_client_get_pid(jack_client_t* client, const char* name);   ? Moreover, declared like that, the implementation on library side is straightforward (because we have 'client'). But it's too late for the API to change. I actually implemented jack_client_get_pid (thus augmenting the API) and can request for a 'to review with care' pull if you are interested. bye