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/error_info_2.cpp

@@ -0,0 +1,49 @@
+//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 add arbitrary data to active exception objects.
+
+#include <boost/exception.hpp>
+#include <boost/shared_ptr.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 file_read_error() << errno_info(errno);
+    }
+
+//
+
+typedef boost::error_info<struct tag_file_name,std::string> file_name_info;
+
+boost::shared_ptr<FILE> file_open( char const * file_name, char const * mode );
+void file_read( FILE * f, void * buffer, size_t size );
+
+void
+parse_file( char const * file_name )
+    {
+    boost::shared_ptr<FILE> f = file_open(file_name,"rb");
+    assert(f);
+    try
+        {
+        char buf[1024];
+        file_read( f.get(), buf, sizeof(buf) );
+        }
+    catch(
+    boost::exception & e )
+        {
+        e << file_name_info(file_name);
+        throw;
+        }
+    }