How to simulate inner exception in C++

Question

Basically I want to simulate .NET Exception.InnerException in C++. I want to catch exception from bottom layer and wrap it with another exception and throw again to upper la

Answer 1

As stated by others, boost::exception is a nice option. However, like all options that use a common base class approach, they rely on all thrown exceptions being derived from that base class. If your intermediary catch handlers need to add information to an exception from a third party library it won't work.

An option that might be sufficient is to have intermediary catch handlers like this:

catch (std::exception& ex)
{
   std::string msg = ex.what();
   msg.append(" - my extra info");
   ex = std::exception(msg.c_str()); // slicing assignment
   throw;                            // re-throws 'ex', preserving it's original type
}

This only works for implementations of std::exception that provide a constructor taking a string parameter (e.g. VC++). The std::exception constructor taking a string is a non-standard extension.