Question

just a quick question. Is there any difference between

void f(Foo x) try
{
   ...
}
catch(exception& e)
{
   ...
}

and

void f(Foo x)
{
    try { ... }
    catch (exception& e)
    {
        ...
    }
}

?

If no, why are function try blocks for (the case of initialization lists for constructors being put aside) ? What happens if the copy constructor of Foo throws an exception when x is passed to f ?

Answer 1

Function try blocks are only ever needed in constructors. In all other cases exactly the same effect can be achieved by enclosing the entire body of the function in a normal try/catch block.

If the copy constructor used to initialize a parameter throws an exception this happens before the function call. It cannot be caught by a function try block or exceptional handler in the function as the function doesn’t get called.