Documentation and examples update.

[SVN r54831]

example/cloning_1.cpp

@@ -6,11 +6,10 @@
 //This example shows how to enable cloning when throwing a boost::exception.
 
 #include <boost/exception/info.hpp>
+#include <boost/exception/errinfo_errno.hpp>
 #include <stdio.h>
 #include <errno.h>
 
-typedef boost::error_info<struct tag_errno,int> errno_info;
-
 class file_read_error: public boost::exception { };
 
 void
@@ -18,5 +17,5 @@ file_read( FILE * f, void * buffer, size_t size )
     {
     if( size!=fread(buffer,1,size,f) )
         throw boost::enable_current_exception(file_read_error()) <<
-            errno_info(errno);
+			boost::errinfo_errno(errno);
     }