6 Jan
2012
6 Jan
'12
11:37 a.m.
On 06-01-12 11:21, Pedro Lopez-Cabanillas wrote:
On Friday 06 January 2012, you wrote:
Thanks,
I was thinking that maybe it would be nicer to connect from my program
to Hydrogen.
Then I don't have to restart Hydrogen everytime my program has ended.
btw: is there a way to list available
clients/ports from the api.
I know that aconnect -i / -o does this, but is there a c/c++ function?
Dave
The functions are: snd_seq_query_next_client() and
snd_seq_query_next_port();
you need to loop calling these functions while they return a correct answer.
For instance, this is the relevant code in "aconnect.c" :
static void do_search_port(snd_seq_t *seq, int perm, action_func_t do_action)
{
snd_seq_client_info_t *cinfo;
snd_seq_port_info_t *pinfo;
int count;
snd_seq_client_info_alloca(&cinfo);
snd_seq_port_info_alloca(&pinfo);
snd_seq_client_info_set_client(cinfo, -1);
while (snd_seq_query_next_client(seq, cinfo)>= 0) {
/* reset query info */
snd_seq_port_info_set_client(pinfo,
snd_seq_client_info_get_client(cinfo));
snd_seq_port_info_set_port(pinfo, -1);
count = 0;
while (snd_seq_query_next_port(seq, pinfo)>= 0) {
if (check_permission(pinfo, perm)) {
do_action(seq, cinfo, pinfo, count);
count++;
}
}
}
}
See:
http://git.alsa-project.org/?p=alsa-utils.git;a=blob;f=seq/aconnect/aconnec…
I guess you already know the reference documentation site:
http://www.alsa-project.org/alsa-doc/alsa-lib/seq.html
Just for comparison, a similar enumeration using Drumstick looks like this:
QListIterator<PortInfo> it(m_Client->getAvailableOutputs());
while(it.hasNext()) {
PortInfo p = it.next();
cout<< p.getClientName()<< ":"<< p.getPort();
} See Drumstick's example "drumgrid":
http://drumstick.sourceforge.net/docs/drumgrid.cpp-example.html
Regards,
Pedro
Dave