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
  23 #include <jack/jack.h>
  24 #include <jack/transport.h>
  25
  26 jack_client_t *client;
  27
  28 static void
  29 showtime ()
  30 {
  31         jack_position_t current;
  32         jack_transport_state_t transport_state;
  33         jack_nframes_t frame_time;
  34
  35         transport_state = jack_transport_query (client, &current);
  36         frame_time = jack_frame_time (client);
  37
  38         printf ("frame = %u  frame_time = %u usecs = %lld \t",  current.frame, frame_time, current.usecs);
  39
  40         switch (transport_state) {
  41         case JackTransportStopped:
  42                 printf ("state: Stopped");
  43                 break;
  44         case JackTransportRolling:
  45                 printf ("state: Rolling");
  46                 break;
  47         case JackTransportStarting:
  48                 printf ("state: Starting");
  49                 break;
  50         default:
  51                 printf ("state: [unknown]");
  52         }
  53
  54         if (current.valid & JackPositionBBT)
  55                 printf ("\tBBT: %3" PRIi32 "|%" PRIi32 "|%04"
  56                         PRIi32, current.bar, current.beat, current.tick);
  57
  58         if (current.valid & JackPositionTimecode)
  59                 printf ("\tTC: (%.6f, %.6f)",
  60                         current.frame_time, current.next_time);
  61         printf ("\n");
  62 }
  63
  64 static void
  65 jack_shutdown (void *arg)
  66 {
  67     fprintf(stderr, "JACK shut down, exiting ...\n");
  68         exit (1);
  69 }
  70
  71 void
  72 signal_handler (int sig)
  73 {
  74         jack_client_close (client);
  75         fprintf (stderr, "signal received, exiting ...\n");
  76         exit (0);
  77 }
  78
  79 int
  80 main (int argc, char *argv[])
  81 {
  82         /* try to become a client of the JACK server */
  83
  84         if ((client = jack_client_open ("showtime", JackNullOption, NULL)) == 0) {
  85                 fprintf (stderr, "JACK server not running?\n");
  86                 return 1;
  87         }
  88
  89         signal (SIGQUIT, signal_handler);
  90         signal (SIGTERM, signal_handler);
  91         signal (SIGHUP, signal_handler);
  92         signal (SIGINT, signal_handler);
  93
  94         /* tell the JACK server to call `jack_shutdown()' if
  95            it ever shuts down, either entirely, or if it
  96            just decides to stop calling us.
  97         */
  98
  99         jack_on_shutdown (client, jack_shutdown, 0);
 100
 101         /* tell the JACK server that we are ready to roll */
 102
 103         if (jack_activate (client)) {
 104                 fprintf (stderr, "cannot activate client");
 105                 return 1;
 106         }
 107
 108         while (1) {
 109                 usleep (20);
 110                 showtime ();
 111         }
 112
 113         jack_client_close (client);
 114         exit (0);
 115 }