On Sat, Jul 21, 2012 at 2:50 PM, Andreas M. Iwanowski <namezero@afim.info> wrote:

Dear boost experts.

We are using boost::exception in a project of ours, and are trying to extract some information from an exception

to display to the user.

For example, diagnostic_information(e) returns this:

d:\projects\<project>\ClassName.cpp(376): Throw in function void __thiscall ClassName::CInetExceptionHandler<struct ClassName::BadLoginException>(class CInternetException *) const

Dynamic exception type: class boost::exception_detail::clone_impl<struct ClassName::BadLoginException>

std::exception::what: Unknown exception

[struct tag_implementation_ClassName_SpecificInfo_errstr *] = Error: 12014 Context: 0 Message: The password was not allowed

[struct tag_interface_CDataInterface_errstr *] = ClassName reports: Bad FTP login

What I want is to extract "Error: 12014 Context: 0 Message: The password was not allowed" or "ClassName reports: Bad FTP login"

from that exception.

However, these exceptions may be generated in DLLs that the main program know nothing about.

To simplify, here is what I do and want ot be happening:

1. Main program calls method in DLL

2. Main program knows this method can throw expections of type boost::exception

3. Main program catches such exception

4. Main program obtains string that is user-friendly from this exception

Use boost::get_error_info. See www.boost.org/doc/libs/release/libs/exception/doc/get_error_info.html.

Ideally, error messages shouldn't be passed in exception objects. Instead, pass the information that the catch site needs to format the message. So, I'd suggest that the "4. Main program obtains a string that is user-friendly" should probably be "4. Main program formats a user-friendly message out of the error_info objects stored in the exception."