Re: [boost] Re: Review: Boost Test Library

From: David Abrahams (abrahams_at_[hidden])
Date: 2001-02-13 18:53:30

Bill,

the try { throw; } idiom is a great way to centralize exception
type-detection (e.g. for reporting) code, but you're right that MSVC has a
problem with multiple destruction in this case. That's I always make sure my
exception classes are resilient to multiple-destruction when targeting MSVC.

-Dave

----- Original Message -----
From: <williamkempf_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Tuesday, February 13, 2001 4:57 PM
Subject: [boost] Re: Review: Boost Test Library

> Just a thought to spark others creativity...
>
> I've been thinking a bit about the desire for catch_exceptions() to
> be able to handle "registered" exception types (during my breaks from
> documenting the BTL, which should be done in a day or two for those
> who are helping me finalize this before submitting), and a trick
> suggested on a programming site I read in the past came to mind
> (sorry, I can't give exact credit here).  Error handling functions
> can be registered and called from catch blocks by using the following
> idiom:
>
> bool handle_my_error_types()
> {
>    try
>    {
>       throw; // re-throw the last exception
>    }
>    catch (my_specific_error_type err)
>    {
>       // handle the error
>       return true; // we handled the error
>    }
>    catch (...)
>    {
>       return false; // we didn't handle the error
>    }
> }
>
> void example()
> {
>    try
>    {
>       // some code that throws
>    }
>    catch (...)
>    {
>       if (handle_my_error_types())
>          cout << "handled" << endl;
>       else
>          cout << "unknown exception type" << endl;
>    }
> }
>
> I think that this idiom could be used to allow test programs
> to "push" handlers for specific exception types that they used onto
> a "handler stack" that would be used by catch_exceptions().  This
> should allow for very specific reports about what exceptions are
> caught by the test framework, even though the framework is not aware
> of library defined exception types.
>
> The one caveat is that (at the time I found this idiom at least) VC++
> couldn't handle this (it tries to destruct the exceptions multiple
> times!).
>
> Any thoughts or comments on the idea?
>
> Bill Kempf
>
>
>
>