Version 3.2

projects/examples/ioN.cpp

@@ -0,0 +1,99 @@
+/******************************************/
+/*
+  Example program for realtime input/output
+  by Gary P. Scavone, 2000
+
+  This program reads N channels of realtime
+  audio input for a specified amount of time
+  and immediately play them back in realtime
+  (duplex mode).  This program also demonstrates
+  the use of FIFO scheduling priority.  To be
+  run with such priority, the program must be
+  set suid (chmod +s) and owned by root.
+*/
+/******************************************/
+
+#include "RtDuplex.h"
+
+#if !defined(__OS_Win_)
+  #include <sched.h>
+#endif
+
+void usage(void) {
+  /* Error function in case of incorrect command-line
+     argument specifications
+  */
+  printf("\nuseage: ioN N time \n");
+  printf("    where N = number of channels,\n");
+  printf("    and time = the amount of time to record (in seconds).\n\n");
+  exit(0);
+}
+
+int
+main(int argc, char *argv[])
+{
+  int i=0;
+
+  // minimal command-line checking
+  if (argc != 3) usage();
+
+  int chans = (int) atoi(argv[1]);
+  float time = atof(argv[2]);
+  float sample_rate = SRATE;
+  MY_FLOAT *inSamples;
+  MY_FLOAT *lastSamples;
+
+  // allocate the lastSamples array
+  lastSamples = (MY_FLOAT *) new MY_FLOAT[chans];
+  for (i=0; i<chans; i++)
+    lastSamples[i] = 0.0;
+
+  // Define and open the realtime duplex device
+  RtDuplex *inout;
+  try {
+    inout = new RtDuplex(chans, sample_rate);
+  }
+  catch (StkError& m) {
+    m.printMessage();
+    exit(0);
+  }
+
+#if !defined(__OS_Win_)
+  // set schedulling priority to SCHED_FIFO
+  struct sched_param p;
+  int min, max, priority;
+
+  if (!getuid() || !geteuid()) {
+    min=sched_get_priority_min(SCHED_FIFO);
+    max=sched_get_priority_max(SCHED_FIFO);
+    priority=min+(max-min)/2;
+    p.sched_priority=priority;
+    if (sched_setscheduler(0, SCHED_FIFO, &p)==-1) {
+	    fprintf(stderr, "\ncould not activate scheduling with priority %d\n", priority);
+    }
+    seteuid(getuid());
+  }
+#endif
+
+  // Here's the runtime loop
+
+  int j=0;
+  int samples = (int) (time*SRATE);
+  while (i<samples) {
+    inSamples = inout->mtick(lastSamples);
+    for (int k=0; k<chans; k++)
+      lastSamples[k] = inSamples[k];
+    i++;
+#if !defined(__OS_Win_)
+    j++;
+    if (j>=256) {
+      sched_yield();
+      j = 0;
+    }
+#endif
+  }
+
+  // Clean up
+  delete inout;
+  delete [] lastSamples;
+}