Re: chained exception

From:

peter koch <peter.koch.larsen@gmail.com>

Newsgroups:

comp.lang.c++

Date:

16 May 2007 09:21:59 -0700

Message-ID:

<1179332519.808311.77860@w5g2000hsg.googlegroups.com>

On 16 Maj, 11:55, josh <xdevel1...@gmail.com> wrote:

On 16 Mag, 10:53, "Sylvester Hesp" <s.h...@oisyn.nl> wrote:

"josh" <xdevel1...@gmail.com> wrote in message

news:1179302043.101088.112800@y80g2000hsf.googlegroups.com...

Hi,
is there a standard way to "read" an exception rethrowed by a catch
and catch in an another extern try/catch?

Thanks

Sure there is, just use nested try/catch statements

#include <iostream>
int main()
{
    try
    {
        try
        {
            std::cout << "throwing..." << std::endl;
            throw 42;
        }
        catch(int i)
        {
            std::cout << "Inner catch: " << i << " - rethrowing..." <<
std::endl;
            throw;
        }
    }
    catch(int i)
    {
        std::cout << "Outer catch: " << i << std::endl;
    }

}

Of course, the inner and outer catches don't have to be in the same
function, and the outer catch can rethrow again if deemed necessary.

- Sylvester

yes but how can I do if I want to save the previous exception object.
In Java in a catch block I can do:

...
catch(Exception e)
{
throw new Exception("new exception", e)

You could create your own exception class for this, but I really do
not see much purpose in that. Rather, I'd create an exception that
derives from both the exceptions you want to combine. And throw thast
one - e.g.

class file_hardware_exception: public file_exception, public
hardware_exception ...

and then the stack trace give me all the exceptions (also who has
caused)

You do not need a stack trace for exception handling. Stack traces are
valuable only when you are debugging stuff, and C++ exceptions were
never meant to be an aid in debugging.
If you'd like to see where an exception is generated, create your own
exception-class and put a breakpoint in the constructor.

/Peter