Catch Multiple Custom Exceptions? – C++

If you have multiple exception types, and assuming there’s a hierarchy of exceptions (and all derived publicly from some subclass of std::exception,) start from the most specific and continue to more general:

try
{
    // throws something
}
catch ( const MostSpecificException& e )
{
    // handle custom exception
}
catch ( const LessSpecificException& e )
{
    // handle custom exception
}
catch ( const std::exception& e )
{
    // standard exceptions
}
catch ( ... )
{
    // everything else
}

On the other hand, if you are interested in just the error message – throw same exception, say std::runtime_error with different messages, and then catch that:

try
{
    // code throws some subclass of std::exception
}
catch ( const std::exception& e )
{
    std::cerr << "ERROR: " << e.what() << std::endl;
}

Also remember – throw by value, catch by [const] reference.