added base() function to the interface of the specialized adaptors

[SVN r21619]

example/function_output_iterator_example.cpp

@@ -0,0 +1,48 @@
+// (C) Copyright Jeremy Siek 2001-2004.
+// Permission to copy, use, modify, sell and distribute this software
+// is granted provided this copyright notice appears in all
+// copies. This software is provided "as is" without express or
+// implied warranty, and with no claim as to its suitability for any
+// purpose.
+
+// Revision History:
+
+// 27 Feb 2001   Jeremy Siek
+//      Initial checkin.
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <boost/function_output_iterator.hpp>
+
+struct string_appender
+{
+    string_appender(std::string& s)
+        : m_str(&s)
+    {}
+    
+    void operator()(const std::string& x) const
+    {
+        *m_str += x;
+    }
+
+    std::string* m_str;
+};
+
+int main(int, char*[])
+{
+  std::vector<std::string> x;
+  x.push_back("hello");
+  x.push_back(" ");
+  x.push_back("world");
+  x.push_back("!");
+
+  std::string s = "";
+  std::copy(x.begin(), x.end(), 
+            boost::make_function_output_iterator(string_appender(s)));
+  
+  std::cout << s << std::endl;
+
+  return 0;
+}