Re: pcap_loop

[Michael Krüger <mickrulist () voipfuture com>]

Am Dienstag, 3. Juni 2008 10:13:49 schrieb m. kh:
> HI
> how to use a the last argument of pcap_loop ?
> in my program i use :
>                      u_char *user;
>                       user="the message ";
>                       pcap_loop(handle, -1, (pcap_handler) callback , user);
>
> but not succe ,help me
> give me example ?

Well this is very useful if you use C++ class instances. In that case you are able to pass the class instance pointer 
to the method, so that a specific class instance is called by the pcap_loop method.

CMyConsumer consumer;

...
pcap_loop(handle, -1, (pcap_handler) callback ,  &consumer);

...

The consumer class needs to have a static member like processData... which does take the packet data as well as the 
user parameter:


...
// this is within the pcap_handler method
CMyConsumer::processData(user /*which is the user data*/, pcap_t* data /*which is the packet data*/
...

The static processData method can now invoke a instance private method of the class to process the data:

void CMyConsumer::processData(void* instance, pcap_t* data)
{
        ((CMyConsumer* )instance)->processInternal(data);
        ... 
} 

Regards,
Michael
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