/** call-seq: write_use() -> int

Returns: the number of write-subscriptions on the port
*/
static VALUE
wrap_snd_seq_port_info_get_write_use(VALUE v_port_info)
{
  snd_seq_port_info_t *port_info;
  Data_Get_Struct(v_port_info, snd_seq_port_info_t, port_info);
  return INT2NUM(snd_seq_port_info_get_write_use(port_info));
}
/*
 * Class:     org_tritonus_lowlevel_alsa_AlsaSeqPortInfo
 * Method:    getWriteUse
 * Signature: ()I
 */
JNIEXPORT jint JNICALL
Java_org_tritonus_lowlevel_alsa_AlsaSeqPortInfo_getWriteUse
(JNIEnv* env, jobject obj)
{
	snd_seq_port_info_t*	handle;
	int			nReturn;

	if (debug_flag) { fprintf(debug_file, "Java_org_tritonus_lowlevel_alsa_AlsaSeqPortInfo_getWriteUse(): begin\n"); }
	handle = getHandle(env, obj);
	nReturn = snd_seq_port_info_get_write_use(handle);
	if (debug_flag) { fprintf(debug_file, "Java_org_tritonus_lowlevel_alsa_AlsaSeqPortInfo_getWriteUse(): end\n"); }
	return nReturn;
}
Exemple #3
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int MidiDriver_ALSA::open() {
	if (_isOpen)
		return MERR_ALREADY_OPEN;
	_isOpen = true;

	if (my_snd_seq_open(&seq_handle) < 0) {
		error("Can't open sequencer");
		return -1;
	}

	my_client = snd_seq_client_id(seq_handle);
	if (snd_seq_set_client_name(seq_handle, "RESIDUALVM") < 0) {
		error("Can't set sequencer client name");
	}
	snd_seq_set_client_group(seq_handle, "input");

	// According to http://www.alsa-project.org/~tiwai/alsa-subs.html
	// you can set read or write capabilities to allow other clients to
	// read or write the port. I don't think we need that, unless maybe
	// to be able to record the sound, but I can't get that to work even
	// with those capabilities.

	my_port = snd_seq_create_simple_port(seq_handle, "RESIDUALVM port 0", 0,
	                                     SND_SEQ_PORT_TYPE_MIDI_GENERIC | SND_SEQ_PORT_TYPE_APPLICATION);

	if (my_port < 0) {
		snd_seq_close(seq_handle);
		error("Can't create port");
		return -1;
	}

	if (seq_client != SND_SEQ_ADDRESS_SUBSCRIBERS) {
		// Subscribe to MIDI port. Prefer one that doesn't already have
		// any connections, unless we've forced a port number already.
		if (seq_port == -1) {
			snd_seq_client_info_t *cinfo;
			snd_seq_port_info_t *pinfo;

			snd_seq_client_info_alloca(&cinfo);
			snd_seq_port_info_alloca(&pinfo);

			snd_seq_get_any_client_info(seq_handle, seq_client, cinfo);

			int first_port = -1;
			int found_port = -1;

			snd_seq_port_info_set_client(pinfo, seq_client);
			snd_seq_port_info_set_port(pinfo, -1);
			while (found_port == -1 && snd_seq_query_next_port(seq_handle, pinfo) >= 0) {
				if (check_permission(pinfo)) {
					if (first_port == -1)
						first_port = snd_seq_port_info_get_port(pinfo);
					if (found_port == -1 && snd_seq_port_info_get_write_use(pinfo) == 0)
						found_port = snd_seq_port_info_get_port(pinfo);
				}
			}

			if (found_port == -1) {
				// Should we abort here? For now, use the first
				// available port.
				seq_port = first_port;
				warning("MidiDriver_ALSA: All ports on client %d (%s) are already in use", seq_client, snd_seq_client_info_get_name(cinfo));
			} else {
				seq_port = found_port;
			}
		}

		if (snd_seq_connect_to(seq_handle, my_port, seq_client, seq_port) < 0) {
			error("Can't subscribe to MIDI port (%d:%d) see README for help", seq_client, seq_port);
		}
	}

	printf("Connected to Alsa sequencer client [%d:%d]\n", seq_client, seq_port);
	printf("ALSA client initialized [%d:0]\n", my_client);

	return 0;
}