example-clients/simple_client.c

   1 /** @file simple_client.c
   2  *
   3  * @brief This simple client demonstrates the basic features of JACK
   4  * as they would be used by many applications.
   5  */
   6
   7 #include <stdio.h>
   8 #include <errno.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <math.h>
  12 #include <signal.h>
  13 #ifndef WIN32
  14 #include <unistd.h>
  15 #endif
  16 #include <jack/jack.h>
  17
  18 jack_port_t *output_port1, *output_port2;
  19 jack_client_t *client;
  20
  21 #ifndef M_PI
  22 #define M_PI  (3.14159265)
  23 #endif
  24
  25 #define TABLE_SIZE   (200)
  26 typedef struct
  27 {
  28         float sine[TABLE_SIZE];
  29         int left_phase;
  30         int right_phase;
  31 }
  32 paTestData;
  33
  34 static void signal_handler(int sig)
  35 {
  36         jack_client_close(client);
  37         fprintf(stderr, "signal received, exiting ...\n");
  38         exit(0);
  39 }
  40
  41 /**
  42  * The process callback for this JACK application is called in a
  43  * special realtime thread once for each audio cycle.
  44  *
  45  * This client follows a simple rule: when the JACK transport is
  46  * running, copy the input port to the output.  When it stops, exit.
  47  */
  48
  49 int
  50 process (jack_nframes_t nframes, void *arg)
  51 {
  52         jack_default_audio_sample_t *out1, *out2;
  53         paTestData *data = (paTestData*)arg;
  54         int i;
  55
  56         out1 = (jack_default_audio_sample_t*)jack_port_get_buffer (output_port1, nframes);
  57         out2 = (jack_default_audio_sample_t*)jack_port_get_buffer (output_port2, nframes);
  58
  59         for( i=0; i<nframes; i++ )
  60         {
  61                 out1[i] = data->sine[data->left_phase];  /* left */
  62                 out2[i] = data->sine[data->right_phase];  /* right */
  63                 data->left_phase += 1;
  64                 if( data->left_phase >= TABLE_SIZE ) data->left_phase -= TABLE_SIZE;
  65                 data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
  66                 if( data->right_phase >= TABLE_SIZE ) data->right_phase -= TABLE_SIZE;
  67         }
  68
  69         return 0;
  70 }
  71
  72 /**
  73  * JACK calls this shutdown_callback if the server ever shuts down or
  74  * decides to disconnect the client.
  75  */
  76 void
  77 jack_shutdown (void *arg)
  78 {
  79         exit (1);
  80 }
  81
  82 int
  83 main (int argc, char *argv[])
  84 {
  85         const char **ports;
  86         const char *client_name;
  87         const char *server_name = NULL;
  88         jack_options_t options = JackNullOption;
  89         jack_status_t status;
  90         paTestData data;
  91         int i;
  92
  93         if (argc >= 2) {                /* client name specified? */
  94                 client_name = argv[1];
  95                 if (argc >= 3) {        /* server name specified? */
  96                         server_name = argv[2];
  97                         int my_option = JackNullOption | JackServerName;
  98                         options = (jack_options_t)my_option;
  99                 }
 100         } else {                        /* use basename of argv[0] */
 101                 client_name = strrchr(argv[0], '/');
 102                 if (client_name == 0) {
 103                         client_name = argv[0];
 104                 } else {
 105                         client_name++;
 106                 }
 107         }
 108
 109         for( i=0; i<TABLE_SIZE; i++ )
 110         {
 111                 data.sine[i] = 0.2 * (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
 112         }
 113         data.left_phase = data.right_phase = 0;
 114
 115
 116         /* open a client connection to the JACK server */
 117
 118         client = jack_client_open (client_name, options, &status, server_name);
 119         if (client == NULL) {
 120                 fprintf (stderr, "jack_client_open() failed, "
 121                          "status = 0x%2.0x\n", status);
 122                 if (status & JackServerFailed) {
 123                         fprintf (stderr, "Unable to connect to JACK server\n");
 124                 }
 125                 exit (1);
 126         }
 127         if (status & JackServerStarted) {
 128                 fprintf (stderr, "JACK server started\n");
 129         }
 130         if (status & JackNameNotUnique) {
 131                 client_name = jack_get_client_name(client);
 132                 fprintf (stderr, "unique name `%s' assigned\n", client_name);
 133         }
 134
 135         /* tell the JACK server to call `process()' whenever
 136            there is work to be done.
 137         */
 138
 139         jack_set_process_callback (client, process, &data);
 140
 141         /* tell the JACK server to call `jack_shutdown()' if
 142            it ever shuts down, either entirely, or if it
 143            just decides to stop calling us.
 144         */
 145
 146         jack_on_shutdown (client, jack_shutdown, 0);
 147
 148         /* create two ports */
 149
 150         output_port1 = jack_port_register (client, "output1",
 151                                           JACK_DEFAULT_AUDIO_TYPE,
 152                                           JackPortIsOutput, 0);
 153
 154         output_port2 = jack_port_register (client, "output2",
 155                                           JACK_DEFAULT_AUDIO_TYPE,
 156                                           JackPortIsOutput, 0);
 157
 158         if ((output_port1 == NULL) || (output_port2 == NULL)) {
 159                 fprintf(stderr, "no more JACK ports available\n");
 160                 exit (1);
 161         }
 162
 163         /* Tell the JACK server that we are ready to roll.  Our
 164          * process() callback will start running now. */
 165
 166         if (jack_activate (client)) {
 167                 fprintf (stderr, "cannot activate client");
 168                 exit (1);
 169         }
 170
 171         /* Connect the ports.  You can't do this before the client is
 172          * activated, because we can't make connections to clients
 173          * that aren't running.  Note the confusing (but necessary)
 174          * orientation of the driver backend ports: playback ports are
 175          * "input" to the backend, and capture ports are "output" from
 176          * it.
 177          */
 178
 179         ports = jack_get_ports (client, NULL, NULL,
 180                                 JackPortIsPhysical|JackPortIsInput);
 181         if (ports == NULL) {
 182                 fprintf(stderr, "no physical playback ports\n");
 183                 exit (1);
 184         }
 185
 186         if (jack_connect (client, jack_port_name (output_port1), ports[0])) {
 187                 fprintf (stderr, "cannot connect output ports\n");
 188         }
 189
 190         if (jack_connect (client, jack_port_name (output_port2), ports[1])) {
 191                 fprintf (stderr, "cannot connect output ports\n");
 192         }
 193
 194         jack_free (ports);
 195
 196     /* install a signal handler to properly quits jack client */
 197 #ifdef WIN32
 198         signal(SIGINT, signal_handler);
 199         signal(SIGABRT, signal_handler);
 200         signal(SIGTERM, signal_handler);
 201 #else
 202         signal(SIGQUIT, signal_handler);
 203         signal(SIGTERM, signal_handler);
 204         signal(SIGHUP, signal_handler);
 205         signal(SIGINT, signal_handler);
 206 #endif
 207
 208         /* keep running until the Ctrl+C */
 209
 210         while (1) {
 211         #ifdef WIN32
 212                 Sleep(1000);
 213         #else
 214                 sleep (1);
 215         #endif
 216         }
 217
 218         jack_client_close (client);
 219         exit (0);
 220 }