Boost Exception

In other libraries, watch for compile error referring to throw_exception_assert_compatibility in boost::throw_exception. Resolve by throwing an exception that derives from std::exception. This is not a new requirement but it is being enforced now.

[SVN r46818]

example/cloning_1.cpp

@@ -0,0 +1,23 @@
+//Copyright (c) 2006-2008 Emil Dotchevski and Reverge Studios, Inc.
+
+//Distributed under the Boost Software License, Version 1.0. (See accompanying
+//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+//This example shows how to enable cloning when throwing a boost::exception.
+
+#include <boost/exception/enable_current_exception.hpp>
+#include <boost/exception/info.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
+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);
+    }