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/** @file simple_client.c
*
* @brief This simple client demonstrates the most basic features of JACK
* as they would be used by many applications.
*/
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <jack/jack.h>
jack_port_t *input_port;
jack_port_t *output_port;
jack_client_t *client;
/**
* The process callback for this JACK application is called in a
* special realtime thread once for each audio cycle.
*
* This client does nothing more than copy data from its input
* port to its output port. It will exit when stopped by
* the user (e.g. using Ctrl-C on a unix-ish operating system)
*/
int
process (jack_nframes_t nframes, void *arg)
{
jack_default_audio_sample_t *in, *out;
in = jack_port_get_buffer (input_port, nframes);
out = jack_port_get_buffer (output_port, nframes);
memcpy (out, in,
sizeof (jack_default_audio_sample_t) * nframes);
return 0;
}
/**
* JACK calls this shutdown_callback if the server ever shuts down or
* decides to disconnect the client.
*/
void
jack_shutdown (void *arg)
{
exit (1);
}
int
main (int argc, char *argv[])
{
const char **ports;
const char *client_name = "simple";
const char *server_name = NULL;
jack_options_t options = JackNullOption;
jack_status_t status;
/* open a client connection to the JACK server */
client = jack_client_open (client_name, options, &status, server_name);
if (client == NULL) {
fprintf (stderr, "jack_client_open() failed, "
"status = 0x%2.0x\n", status);
if (status & JackServerFailed) {
fprintf (stderr, "Unable to connect to JACK server\n");
}
exit (1);
}
if (status & JackServerStarted) {
fprintf (stderr, "JACK server started\n");
}
if (status & JackNameNotUnique) {
client_name = jack_get_client_name(client);
fprintf (stderr, "unique name `%s' assigned\n", client_name);
}
/* tell the JACK server to call `process()' whenever
there is work to be done.
*/
jack_set_process_callback (client, process, 0);
/* tell the JACK server to call `jack_shutdown()' if
it ever shuts down, either entirely, or if it
just decides to stop calling us.
*/
jack_on_shutdown (client, jack_shutdown, 0);
/* display the current sample rate.
*/
printf ("engine sample rate: %" PRIu32 "\n",
jack_get_sample_rate (client));
/* create two ports */
input_port = jack_port_register (client, "input",
JACK_DEFAULT_AUDIO_TYPE,
JackPortIsInput, 0);
output_port = jack_port_register (client, "output",
JACK_DEFAULT_AUDIO_TYPE,
JackPortIsOutput, 0);
if ((input_port == NULL) || (output_port == NULL)) {
fprintf(stderr, "no more JACK ports available\n");
exit (1);
}
/* Tell the JACK server that we are ready to roll. Our
* process() callback will start running now. */
if (jack_activate (client)) {
fprintf (stderr, "cannot activate client");
exit (1);
}
/* Connect the ports. You can't do this before the client is
* activated, because we can't make connections to clients
* that aren't running. Note the confusing (but necessary)
* orientation of the driver backend ports: playback ports are
* "input" to the backend, and capture ports are "output" from
* it.
*/
ports = jack_get_ports (client, NULL, NULL,
JackPortIsPhysical|JackPortIsOutput);
if (ports == NULL) {
fprintf(stderr, "no physical capture ports\n");
exit (1);
}
if (jack_connect (client, ports[0], jack_port_name (input_port))) {
fprintf (stderr, "cannot connect input ports\n");
}
free (ports);
ports = jack_get_ports (client, NULL, NULL,
JackPortIsPhysical|JackPortIsInput);
if (ports == NULL) {
fprintf(stderr, "no physical playback ports\n");
exit (1);
}
if (jack_connect (client, jack_port_name (output_port), ports[0])) {
fprintf (stderr, "cannot connect output ports\n");
}
free (ports);
/* keep running until stopped by the user */
sleep (-1);
/* this is never reached but if the program
had some other way to exit besides being killed,
they would be important to call.
*/
jack_client_close (client);
exit (0);
}
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