3) Support for linking multiple error tags in a single expression might be useful and help in standarizing errors throughout an application.
throw boost:::exception() << boost::error_info<tag_errorno,tag_filename,tag_size,tag_width>( (1,"output.txt",100,200);
Could you clarify what you mean?
Well, I could do something like this: typedef boost::error_info<tag_errorno, tag_filename,tag_size,tag_width> error_t; throw error_t(1,"output.txt",100,200); If this error was common throughtout an application, this typedef would make the code more readable. Many boost components support variable number of template arguments. It would be trivial to implement I think. You could even default the template arguments, to shorten the expression even further, such as: typedef boost::standard_error<> standard_error_t; throw standard_error_t(); You could do this instead of the "ugly" macros that you have for the "_LINE_", "_FILE_" and "_FUNCTION_".
Usage of the stream operator (<<) for data insertion.
I like using (<<) for data insertion and see no reason to remove it.