[Omnetpp-l] cannot cast cMessage to cPacket

[Vitali Anselm]

Hello,

I use some functions like getByteLength() in my handleMessage(cMessage *msg) function, so I decided to cast msg to cPacket to be able to use these functions. For this I wrote the following code:

cPacket *tempPtr = check_and_cast<cPacket *>(msg);

and then I use tempPtr at places, where the cPacket functions are called.

When I compile all, there is no errors, but when I want to run TKenv there is
the following error:

Error in module(.....):
check_and_cast():cannot cast (cMessage*).......[0].per_second_timer to type
"P7cPacket".

per_second_timer is declared as cMessage:

per_second_timer = new cMessage("per_second_timer");
scheduleAt(simTime(), per_second_timer);

Can you help me?

regards,

Vitali
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[Ahmed]

Hello,

try to use cPacket * PK(cMessage  *) to cast cMessage to cPacket.

regards,
--
Ahmed

[Alfonso Ariza Quintana]

it's inherit problem

cPacket is a descendant of cMessage

if you create a

cPacket *pkt = new cPacket();
cMessage *msg = pkt; // Valid   cPacket is a descendant of cMessage
cPacket *pkt2 = dynamic_cast<cPacket*>(msg);


 pkt2 <> null because msg containt a cPacket


 but if you do

cMessage *msg = new cMessage();
cPacket *pkt2 = dynamic_cast<cPacket*>(msg);

pkt2 = NULL because msg not contain a cPacket, contain a cMessage


> Date: Tue, 7 Apr 2009 10:42:04 +0200
> From: Vitali...@web.de
> To: omne...@omnetpp.org
> Subject: [Omnetpp-l] cannot cast cMessage to cPacket

---

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[ktn varma]

So, can someone help me with a solution to this problem...

[Rudolf Hornig]

This is a 4 year old topic. If you are interested in the solution:

an object with dynamic type cMessage cannot be cast to cPacket. That's why the code has failed on check_and_cast