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diff --git a/gr-audio/examples/c++/dial_tone.cc b/gr-audio/examples/c++/dial_tone.cc
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+++ b/gr-audio/examples/c++/dial_tone.cc
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+/*
+ * Copyright 2011 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+/*
+ * GNU Radio C++ example creating dial tone
+ * ("the simplest thing that could possibly work")
+ *
+ * Send a tone each to the left and right channels of stereo audio
+ * output and let the user's brain sum them.
+ *
+ * GNU Radio makes extensive use of Boost shared pointers.  Signal processing
+ * blocks are typically created by calling a "make" factory function, which
+ * returns an instance of the block as a typedef'd shared pointer that can
+ * be used in any way a regular pointer can.  Shared pointers created this way
+ * keep track of their memory and free it at the right time, so the user
+ * doesn't need to worry about it (really).
+ *
+ */
+
+// Include header files for each block used in flowgraph
+#include <gr_top_block.h>
+#include <gr_sig_source_f.h>
+#include <gr_audio_sink.h>
+
+int main(int argc, char **argv)
+{
+  int rate = 48000;		// Audio card sample rate
+  float ampl = 0.1;		// Don't exceed 0.5 or clipping will occur
+
+  // Construct a top block that will contain flowgraph blocks.  Alternatively,
+  // one may create a derived class from gr_top_block and hold instantiated blocks
+  // as member data for later manipulation.
+  gr_top_block_sptr tb = gr_make_top_block("dial_tone");
+
+  // Construct a real-valued signal source for each tone, at given sample rate
+  gr_sig_source_f_sptr src0 = gr_make_sig_source_f(rate, GR_SIN_WAVE, 350, ampl);
+  gr_sig_source_f_sptr src1 = gr_make_sig_source_f(rate, GR_SIN_WAVE, 440, ampl);
+
+  // Construct an audio sink to accept audio tones
+  audio_sink::sptr sink = audio_make_sink(rate);
+
+  // Connect output #0 of src0 to input #0 of sink (left channel)
+  tb->connect(src0, 0, sink, 0);
+
+  // Connect output #0 of src1 to input #1 of sink (right channel)
+  tb->connect(src1, 0, sink, 1);
+
+  // Tell GNU Radio runtime to start flowgraph threads; the foreground thread
+  // will block until either flowgraph exits (this example doesn't) or the
+  // application receives SIGINT (e.g., user hits CTRL-C).
+  //
+  // Real applications may use tb->start() which returns, allowing the foreground
+  // thread to proceed, then later use tb->stop(), followed by tb->wait(), to cleanup
+  // GNU Radio before exiting.
+  tb->run();
+
+  // Exit normally.
+  return 0;
+}