Code reuse in exception handling

Question

I'm developing a C api for some functionality written in C++ and I want to make sure that no exceptions are propagated out of any of the exported C functions.

The simple way to do it is making sure each exported function is contained in a:

try {
   // Do the actual code
} catch (...) {
   return ERROR_UNHANDLED_EXCEPTION;
}

Let's say I know one exception that is often missed inside the C++ code is std::bad_alloc and I want to treat it specially I'd write something like this instead:

try {
   // Run the actual code
} catch (std::bad_alloc& e) {
   return ERROR_BAD_ALLOC;
} catch (...) {
   return ERROR_UNHANDLED_EXCEPTION;
}

Is it possible to decompose this in some clever way so that I can globally treat some errors differently without adding a new catch statement for the exception handler around every exported function?

I'm aware of that this is possible to solve using the preprocessor, but before going down that road, I'd make sure there is no other way to do it.

Answer 1

You can use only one handler function for all possible exceptions, and call it from each or your API implementation functions, as below:

int HandleException()
{
    try 
    {
        throw;
    }

    // TODO: add more types of exceptions

    catch( std::bad_alloc & ) 
    {
       return ERROR_BAD_ALLOC;
    }
    catch( ... )
    {
        return ERROR_UNHANDLED_EXCEPTION;
    }
}

And in each exported function:

try
{
    ...
}
catch( ... )
{
    return HandleException();
}

Answer 2

There already is a good answer. But just FYI, its called 'exception-dispatcher' idiom, see C++ FAQ.