[Click] dynamic_cast ?

[Eddie Kohler]

Hi Harald,

Click already provides a cast() method on Element that should do what 
you want.

http://www.read.cs.ucla.edu/click/doxygen/classElement.html#e19904c6060f3d4411e32cba0dd2e3c1

So something like

Foo *foo = (Foo *) output(0).element()->cast("Foo");

Eddie


Harald Schiöberg wrote:
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> Michael Neufeld wrote:
>> Last time I looked Linux kernel mode Click disables RTTI (as well as
>> exceptions), so I wouldn't expect dynamic_cast to work in the Linux kernel.
>>
>> -Mike
> 
> Thanks, that's what I almost anticipated. Is there any other solution
> that does the same thing in click, some method of Element that one can
> use? Basically I need to find out at initialization time whether my
> neighbor elements are derived from a special subclass of element.
> 
> The "dirty" way would be to implement a "i_am_foo" handler and check for
> it's existence....
> 
> 	harald
> 
>> Harald Schiöberg wrote:
>> does anyone know whether this is safe to do in click ?
>>
>> class Foo : public Element { ... }
>> class FooBar : public Foo { ... }
>>
>> Foo::some_method() {
>>     Element downstream;
>>     downstream  = output[0].element();
>>
>>     if ( dynamic_cast<Foo>(e) ) {
>>     ... e is a foo ...
>>     } else {
>>     .... e is not a foo ...
>>     }
>> }
>>
>> I currently have no linuxkernel installation, so I can't check for this
>> case, but I see potential breakage, since this requires a bit of
>> compiler magic.
>>
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> - --
> Harald Schiöberg
> Technische Universität Berlin | T-Laboratories | FG INET
> www: http://www.net.t-labs.tu-berlin.de
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