Re: Deleting exceptions after throwing

From:

Emil Berg <emilbergg@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 24 Sep 2009 05:40:13 -0700 (PDT)

Message-ID:

<d343f4c3-6517-49f2-82e3-8bbc59b9c832@e34g2000vbm.googlegroups.com>

On Sep 24, 3:18 pm, p...@informatimago.com (Pascal J. Bourguignon)
wrote:

Emil Berg <emilbe...@gmail.com> writes:

On Sep 24, 1:57 pm, Alan Woodland <aj...@aber.ac.uk> wrote:

Emil Berg wrote:

[snip]

What I want to do is pass exceptions between threads. I have some
exception classes that derive from CBaseException class.
Now I'm doing the following steps:
1. Throw FileNotFoundException on thread A
2. Catch it as CBaseException and save it in an CBaseException*
pointer.
3. Pass this pointer to thread B
4. Throw this exception manually.
5. Catching the exception on thread B as FileNotFoundException
reference

Steps 2,3,4 are part of a threading/messaging infrastructure that I'=

building, so I'd like to delete the exception on thread B after
throwing it (inside the infrastructure).
I don't want the user to delete the exception.

I hope that I explained it well and maybe you have a good idea to
solve it.

Why not use something like auto_ptr around step 4 so that when you hit
the throw it gets deleted during stack unwinding?

Alan

If I throw auto_ptr<FileNotFoundException> then the user needs to
catch auto_ptr<FileNotFoundException>.
I want the user to catch just FileNotFoundException and not its
auto_ptr.

class TheActualFileNotFoundException:public std::exception {
...};

typedef auto_ptr<TheActualFileNotFoundException> FileNotFoundException;

--
__Pascal Bourguignon__

So the user needs to catch FileNotFoundException and call get()
function to get the actual exception.
It's more complicated for the user from just deleting it :)