Re: Exceptions, Go to Hell!

From:

Goran Pusic <goranp@cse-semaphore.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 26 Aug 2010 04:43:05 -0700 (PDT)

Message-ID:

<f966861a-3bf8-457e-b5cc-efa389f78892@x25g2000yqj.googlegroups.com>

On Aug 26, 10:26 am, Kai-Uwe Bux <jkherci...@gmx.net> wrote:

I am curious: if I use a function that communicates failure (or some othe=

condition) via throwing, how can RAII or ScopeGuard help me to avoid a ca=

tch

statement?

Well... I __guessed__ that OP who complained about try/catch had too
many of them (perhaps I was wrong), and that they were caused by the
following situations:

{
  TYPE r = alloc(); // r holds a resource; we must free it at the
block end.
  workworkwork(); might throw, or simply return prematurely
  free(r);
}

so you'd do:

{
  TYPE r = alloc();
  try
  {
    workworkwork();
    free(r);
  }
  catch(...)
  {
    free(r); // must be a no-throw operation.
    throw;
  }
}

This alone is ugly, now imagine that you have another (or more)
resources in that block.

So, if you use RAII (that is, have resource-wrapper class for TYPE),
or scope guard, try/catch-es like above all disappear (as well as
multiple calls to free).

The number of "other types" of try/catch statements in code is IMO
very, very small. And the bigger the code base, the smaller it is
(compared to said size).

Goran.