How can you make exception handling fall through multiple catch blocks in a single case?

Question

Let's say you have the following hierarchy. You have a base class Animal, with a bunch of sub classes like Cat, Mouse, Dog, etc.

Now, we have the following scenario:

void ftn()
{
   throw Dog();
}

int main()
{
   try
   {
       ftn();
   }
   catch(Dog &d)
   {
    //some dog specific code
   }
   catch(Cat &c)
   {
    //some cat specific code
   }
   catch(Animal &a)
   {
    //some generic animal code that I want all exceptions to also run
   }
}

So, what I want is that even if a Dog is thrown, I want the Dog catch case to execute, and also the Animal catch case to execute. How do you make this happen?

Answer 1

Another alternative (aside from the try-within-a-try) is to isolate your generic Animal-handling code in a function that is called from whatever catch blocks you want:

void handle(Animal const & a)
{
   // ...
}

int main()
{
   try
   {
      ftn();
   }
   catch(Dog &d)
   {
      // some dog-specific code
      handle(d);
   }
   // ...
   catch(Animal &a)
   {
      handle(a);
   }
}

Answer 2

AFAIK, you need to split that in two try-catch-blocks and rethrow:

void ftn(){
   throw Dog();
}

int main(){
   try{
     try{
       ftn();
     }catch(Dog &d){
      //some dog specific code
      throw; // rethrows the current exception
     }catch(Cat &c){
      //some cat specific code
      throw; // rethrows the current exception
     }
   }catch(Animal &a){
    //some generic animal code that I want all exceptions to also run
   }
}