example-clients/showtime.c

   1 /*
   2     This program is free software; you can redistribute it and/or modify
   3     it under the terms of the GNU General Public License as published by
   4     the Free Software Foundation; either version 2 of the License, or
   5     (at your option) any later version.
   6
   7     This program is distributed in the hope that it will be useful,
   8     but WITHOUT ANY WARRANTY; without even the implied warranty of
   9     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10     GNU General Public License for more details.
  11
  12     You should have received a copy of the GNU General Public License
  13     along with this program; if not, write to the Free Software
  14     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  15 */
  16
  17 #include <stdio.h>
  18 #include <errno.h>
  19 #include <unistd.h>
  20 #include <signal.h>
  21 #include <stdlib.h>
  22 #include <inttypes.h>
  23
  24 #include <jack/jack.h>
  25 #include <jack/transport.h>
  26
  27 jack_client_t *client;
  28
  29 static void
  30 showtime ()
  31 {
  32         jack_position_t current;
  33         jack_transport_state_t transport_state;
  34         jack_nframes_t frame_time;
  35
  36         transport_state = jack_transport_query (client, &current);
  37         frame_time = jack_frame_time (client);
  38
  39         printf ("frame = %u  frame_time = %u usecs = %" PRIu64 "\t",  current.frame, frame_time, current.usecs);
  40
  41         switch (transport_state) {
  42         case JackTransportStopped:
  43                 printf ("state: Stopped");
  44                 break;
  45         case JackTransportRolling:
  46                 printf ("state: Rolling");
  47                 break;
  48         case JackTransportStarting:
  49                 printf ("state: Starting");
  50                 break;
  51         default:
  52                 printf ("state: [unknown]");
  53         }
  54
  55         if (current.valid & JackPositionBBT)
  56                 printf ("\tBBT: %3" PRIi32 "|%" PRIi32 "|%04"
  57                         PRIi32, current.bar, current.beat, current.tick);
  58
  59         if (current.valid & JackPositionTimecode)
  60                 printf ("\tTC: (%.6f, %.6f)",
  61                         current.frame_time, current.next_time);
  62         printf ("\n");
  63 }
  64
  65 static void
  66 jack_shutdown (void *arg)
  67 {
  68     fprintf(stderr, "JACK shut down, exiting ...\n");
  69         exit (1);
  70 }
  71
  72 void
  73 signal_handler (int sig)
  74 {
  75         jack_client_close (client);
  76         fprintf (stderr, "signal received, exiting ...\n");
  77         exit (0);
  78 }
  79
  80 int
  81 main (int argc, char *argv[])
  82 {
  83         /* try to become a client of the JACK server */
  84
  85         if ((client = jack_client_open ("showtime", JackNullOption, NULL)) == 0) {
  86                 fprintf (stderr, "JACK server not running?\n");
  87                 return 1;
  88         }
  89
  90 #ifndef WIN32
  91         signal (SIGQUIT, signal_handler);
  92         signal (SIGHUP, signal_handler);
  93 #endif
  94
  95         signal (SIGTERM, signal_handler);
  96         signal (SIGINT, signal_handler);
  97
  98         /* tell the JACK server to call `jack_shutdown()' if
  99            it ever shuts down, either entirely, or if it
 100            just decides to stop calling us.
 101         */
 102
 103         jack_on_shutdown (client, jack_shutdown, 0);
 104
 105         /* tell the JACK server that we are ready to roll */
 106
 107         if (jack_activate (client)) {
 108                 fprintf (stderr, "cannot activate client");
 109                 return 1;
 110         }
 111
 112         while (1) {
 113                 usleep (20);
 114                 showtime ();
 115         }
 116
 117         jack_client_close (client);
 118         exit (0);
 119 }