4 files changed, 21 insertions, 0 deletions
diff --git a/gnuradio-core/src/lib/io/gr_file_sink.cc b/gnuradio-core/src/lib/io/gr_file_sink.cc
index d40235fab..d2c43aac7 100644
--- a/gnuradio-core/src/lib/io/gr_file_sink.cc
+++ b/gnuradio-core/src/lib/io/gr_file_sink.cc
@@ -70,5 +70,8 @@ gr_file_sink::work (int noutput_items,
     nwritten += count;
     inbuf += count * d_itemsize;
   }
+  if (d_unbuffered)
+	  fflush (d_fp);
+	  
   return nwritten;
 }
diff --git a/gnuradio-core/src/lib/io/gr_file_sink_base.cc b/gnuradio-core/src/lib/io/gr_file_sink_base.cc
index 5ddeeb4d5..c43304b0d 100644
--- a/gnuradio-core/src/lib/io/gr_file_sink_base.cc
+++ b/gnuradio-core/src/lib/io/gr_file_sink_base.cc
@@ -118,3 +118,9 @@ gr_file_sink_base::do_update()
     d_updated = false;
   }
 }  
+
+void
+gr_file_sink_base::set_unbuffered(bool unbuffered)
+{
+	d_unbuffered = unbuffered;
+}
diff --git a/gnuradio-core/src/lib/io/gr_file_sink_base.h b/gnuradio-core/src/lib/io/gr_file_sink_base.h
index 0c028d7fd..7b96cdb7f 100644
--- a/gnuradio-core/src/lib/io/gr_file_sink_base.h
+++ b/gnuradio-core/src/lib/io/gr_file_sink_base.h
@@ -37,6 +37,7 @@ class gr_file_sink_base
   bool		d_updated;	// is there a new FILE pointer?
   bool		d_is_binary;
   boost::mutex	d_mutex;
+  bool		d_unbuffered;
 
  protected:
   gr_file_sink_base(const char *filename, bool is_binary);
@@ -61,6 +62,12 @@ class gr_file_sink_base
    * \brief if we've had an update, do it now.
    */
   void do_update();
+  
+  
+  /*!
+   * \brief turn on unbuffered writes for slower outputs
+   */
+  void set_unbuffered(bool unbuffered);
 };
 
 
diff --git a/gnuradio-core/src/lib/io/gr_file_sink_base.i b/gnuradio-core/src/lib/io/gr_file_sink_base.i
index 05a3353bb..ed4342482 100644
--- a/gnuradio-core/src/lib/io/gr_file_sink_base.i
+++ b/gnuradio-core/src/lib/io/gr_file_sink_base.i
@@ -43,4 +43,9 @@ class gr_file_sink_base
    * \brief if we've had an update, do it now.
    */
   void do_update();
+
+  /*!
+   *\brief turn on unbuffered mode for slow outputs
+   */
+  void set_unbuffered(bool unbuffered);
 };