Re: [Boost-users] [boost::variant] problems with pointers

From: David Klein (dave_chp_at_[hidden])
Date: 2007-05-09 18:08:50

Jeffrey Holle wrote:
> After much inefficient debugging, I've discovered that adding a pointer 
> type to a boost::variant is a no-no.  It appears to get translated into 
> a bool via get<>, which throws a bad_get exception erroneously (at least 
> in my opinion).
>
> The caviots of using a pointer type in variant really needs to be 
> documented!  It doesn't appear to be done so now.
>
> I've discovered that wrapping the pointer in a boost::shared_pointer is 
> a solution.  But it wasn't obvious.
>
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>
>   
Hi Jeffrey,

f.ex:

variant<int *, double *> v;

int i = 12345;
v = &i;   
cout << *get<int *>(v) << endl;
 
double d = 1.2345;
v = &d;
cout << *get<double *>(v) << endl;
cout << *get<int *>(v) << endl;

output is:
12345
1.2345
*exception*

Thats exactly what I would expect. Am I missing something?

(tested with boost_1_34_beta + gcc 3.4.2)

--
Regards,
dave