Imported Upstream version 4.2-build2006upstream/4.2-build2006upstream

1 files changed, 154 insertions, 0 deletions

diff --git a/tutorials/sndkit/samples/dsp_geterror_demo.c b/tutorials/sndkit/samples/dsp_geterror_demo.c
new file mode 100644
index 0000000..793de09
--- /dev/null
+++ b/tutorials/sndkit/samples/dsp_geterror_demo.c
@@ -0,0 +1,154 @@
+/*
+ * Purpose: A simple demonstration of 
+ * Copyright (C) 4Front Technologies, 2007. All rights reserved.
+ *
+ * Description:
+ * This program is seriously broken. It's only purpose is to fail so that
+ * the !nlink SNDCTL_DSP_GETERROR} ioctl call can be tested. Otherwise this 
+ * program is based on the {!nlink singen.c} program.
+ *
+ * However this program demonstrates how SNDCTL_DSP_GETERROR can be used in 
+ * applications.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <soundcard.h>
+
+int fd_out;
+
+static int
+open_audio_device (char *name, int mode)
+{
+  int tmp, fd;
+  int sample_rate;
+
+  if ((fd = open (name, mode, 0)) == -1)
+    {
+      perror (name);
+      exit (-1);
+    }
+
+/*
+ * Setup the device. Note that it's important to set the
+ * sample format, number of channels and sample rate exactly in this order.
+ * Some devices depend on the order.
+ */
+
+/*
+ * Set the sample format
+ */
+  tmp = AFMT_S16_NE;		/* Native 16 bits */
+  if (ioctl (fd, SNDCTL_DSP_SETFMT, &tmp) == -1)
+    {
+      perror ("SNDCTL_DSP_SETFMT");
+      exit (-1);
+    }
+
+  if (tmp != AFMT_S16_NE)
+    {
+      fprintf (stderr,
+	       "The device doesn't support the 16 bit sample format.\n");
+      exit (-1);
+    }
+
+/*
+ * Set the number of channels
+ */
+  tmp = 1;
+  if (ioctl (fd, SNDCTL_DSP_CHANNELS, &tmp) == -1)
+    {
+      perror ("SNDCTL_DSP_CHANNELS");
+      exit (-1);
+    }
+
+  if (tmp != 1)
+    {
+      fprintf (stderr, "The device doesn't support mono mode.\n");
+      exit (-1);
+    }
+
+/*
+ * Set the sample rate
+ */
+  sample_rate = 48000;
+  if (ioctl (fd, SNDCTL_DSP_SPEED, &sample_rate) == -1)
+    {
+      perror ("SNDCTL_DSP_SPEED");
+      exit (-1);
+    }
+
+/*
+ * No need for error checking because we will automatically adjust the
+ * signal based on the actual sample rate. However most application must
+ * check the value of sample_rate and compare it to the requested rate.
+ *
+ * Small differences between the rates (10% or less) are normal and the
+ * applications should usually tolerate them. However larger differences may
+ * cause annoying pitch problems (Mickey Mouse).
+ */
+
+  return fd;
+}
+
+int
+main (int argc, char *argv[])
+{
+  char *name_out = "/dev/dsp";
+  int tmp;
+
+  audio_errinfo ei;
+  audio_buf_info bi;
+
+  if (argc > 1)
+    name_out = argv[1];
+
+  fd_out = open_audio_device (name_out, O_WRONLY);
+
+/*
+ * Cause an intentional error by using wrong parameter to SNDCTL_DSP_STEREO
+ * which expects 0 or 1. Don't do error checking in this case because
+ * we would like to see two errors reported.
+ */
+  tmp = 2;
+  ioctl (fd_out, SNDCTL_DSP_STEREO, &tmp);
+
+/*
+ * Cause an intentional failure by calling {!nlink SNDCTL_DSP_GETISPACE}
+ * which is not permitted on write-only devices.
+ */
+
+  if (ioctl (fd_out, SNDCTL_DSP_GETISPACE, &bi) == -1)
+    {
+      perror ("SNDCTL_DSP_GETISPACE");	/* Report the "primary" error first */
+
+      /*
+       * Next show the explanation to the user.
+       */
+      fprintf (stderr,
+	       "Audio error: Cannot obtain recorded byte count from the device.\n");
+      fprintf (stderr, "\n");
+
+      /*
+       * Next call {!nlink SNDCTL_DSP_GETERROR} to see if there is
+       * any additional info available.
+       */
+
+      if (ioctl (fd_out, SNDCTL_DSP_GETERROR, &ei) != -1)
+	{
+	  if (ei.play_errorcount > 0 && ei.play_lasterror != 0)
+	    fprintf (stderr, "%d OSS play event(s), last=%05d:%d\n",
+		     ei.play_errorcount, ei.play_lasterror,
+		     ei.play_errorparm);
+
+	  if (ei.rec_errorcount > 0 && ei.rec_lasterror != 0)
+	    fprintf (stderr, "%d OSS rec event(s), last=%05d:%d\n",
+		     ei.rec_errorcount, ei.rec_lasterror, ei.rec_errorparm);
+	}
+    }
+  else
+    fprintf (stderr, "SNDCTL_DSP_GETISPACE didn't fail as expected.\n");
+
+  exit (0);
+}