CGAL users discussion list

[Giles Bathgate <>]

C++ destructors should never throw exceptions (they should provide the
"nofail" Exception Guarantee).

In the C++ Programming Language (Third Edition)" by Bjarne Stroustrup,
 Stroustrup says: "The standard library function uncaught_ exception()
returns true if an exception has been thrown but hasn't yet been
caught. This allows the programmer to specify different actions in a
destructor depending on whether an object is destroyed normally or as
part of stack unwinding." .

try
{
// [ ... ]
}
catch(...)
{
if(std::uncaught_exception() == false)
throw;
}

My patch adds the std::uncaught_exception() check to the standard
CGAL_Assertion macro (for that file only)

This works in standard compilers like GCC , but it is not reported to
work on some deviated ones like some versions of Visual C++.

(sourced from the C2.com wiki)

Regards,
Giles

On 20 February 2015 at 20:01, Marius Kintel 
<>
 wrote:
> On Feb 20, 2015, at 14:55 PM, Sebastien Loriot (GeometryFactory) 
> <>
>  wrote:
>> In the meantime you can try:
>> #define CGAL_CT2_WANTS_TO_HAVE_EXTRA_ACTION_FOR_INTERSECTING_CONSTRAINTS
>> #define CGAL_CDT2_EXTRA_ACTION_FOR_INTERSECTING_CONSTRAINTS throw 
>> WhatEverException;
>>
>> This will allow you to throw an exception if constraints intersect.
>>
> Not sure that would make a difference. If those defines are not there, the 
> default action is "CGAL_triangulation_assertion(false);”
> ..which throws an exception. The presence of this exception is what causes 
> the later crash.
>
> My understanding is that what we need is to _not_ throw _any_ exceptions in 
> destructors, as that requires a guarantee that no existing exceptions can 
> be active. Such a guarantee is probably hard or tedious to maintain.
>
>  -Marius
>
>
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