Version 4.0

projects/examples/io.cpp

@@ -0,0 +1,87 @@
+/******************************************/
+/*
+  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"
+#include <stdio.h>
+
+#if defined(__OS_LINUX_) || defined(__OS_IRIX__)
+  #include <sched.h>
+#endif
+
+void usage(void) {
+  // Error function in case of incorrect command-line
+  // argument specifications.
+  printf("\nuseage: io N time \n");
+  printf("    where N = number of channels,\n");
+  printf("    and time = the amount of time to run (in seconds).\n\n");
+  exit(0);
+}
+
+int
+main(int argc, char *argv[])
+{
+  // Minimal command-line checking.
+  if (argc != 3) usage();
+
+  unsigned int channels = (unsigned int) atoi(argv[1]);
+  float time = atof(argv[2]);
+
+  // Open the realtime duplex device.
+  RtDuplex *inout = 0;
+  try {
+    inout = new RtDuplex(channels, Stk::sampleRate(), 0, RT_BUFFER_SIZE, 10);
+  }
+  catch (StkError &) {
+    exit(0);
+  }
+
+#if defined(__OS_LINUX__) || defined(__OS_IRIX__)
+  // 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
+  unsigned long i, counter = 0;
+  MY_FLOAT *newFrame = new MY_FLOAT[channels];
+  const MY_FLOAT *lastFrame = inout->lastFrame();
+  unsigned long samples = (unsigned long) (time * Stk::sampleRate());
+  while ( counter < samples ) {
+    for ( i=0; i<channels; i++ )
+      newFrame[i] = lastFrame[i];
+    lastFrame = inout->tickFrame( newFrame );
+    counter++;
+#if defined(__OS_LINUX__) || defined(__OS_IRIX__)
+    if ( counter % 1024 == 0 )
+      sched_yield();
+#endif
+  }
+
+  // Clean up
+  delete [] newFrame;
+  delete inout;
+  return 0;
+}