Re: Why C++ Is Not ???Back???

On Wednesday, December 5, 2012 7:36:26 PM UTC+1, Luca Risolia wrote:


If you want that, then you can do:

try
{
  TYPE instance = new TYPE(...);
  try
  {
    use(instance);
  }
  finally
  {
    instance.close(); // etc.
  }
}
finally
{
 // Your "additional" code here.
}

True, this is longer in pure lines of code, but IMO
the intention is clearer than with an if.


Well, for that, same as above, really: you wrap the whole of the function i=
nto a try-catch and rethrow your exception wrapping the original. I would f=
urther argue that you have to do that anyhow. Say that the code is (conside=
ring the "standard" Java "wrap/rethrow" approach to checked exceptions):

void f() throws myException
{
  try
  {
   TYPE instance = new TYPE(...);
   use(instance);
   instance.close();
  }
  catch(Exception e)
  {
    try
    {
      if (instance != null) instance.close();
    }
    catch(Exception e)
    {
       throw new myException(msg, e);
    }
    throw new myException(msg, e);
  }
}

with what I propose, you get

void f() throws myException
{
  try
  {
    TYPE instance = new TYPE(...);
    try
    {
      use(instance);
    }
    finally
    {
      instance.close();
    }
  }
  catch(Exception e)
  {
    throw new myException(msg, e);
  }
}

which is not much different. In fact, there's less duplicated code in the l=
atter (only one call to instance.close, only one "rethrow").


Me neither. I think, because it's cumbersome, people dodge the question in =
various ways (e.g. catch(Exception) {/*swallow*/ }) and get poor end result=
s anyhow ;-).

Goran.