[Winpcap-users] pcap_loop pointers

ceo at triplebit.com ceo at triplebit.com
Tue Sep 11 16:07:08 GMT 2007

Thanks GV,
I experimented a little and saw that if I assign global pointers with the outcome pointers values from the function, they sustain to point to the original pointers data even if I leave the function.
Does that make sense with your reply?
Can I use these global pointers values after returning from the function? 
I. Lesher
  ----- Original Message ----- 
  From: Gianluca Varenni 
  To: ceo at triplebit.com ; winpcap-users at winpcap.org 
  Sent: Tuesday, September 11, 2007 8:34 AM
  Subject: Re: [Winpcap-users] pcap_loop pointers

    ----- Original Message ----- 
    From: ceo at triplebit.com 
    To: winpcap-users at winpcap.org 
    Sent: Monday, September 10, 2007 6:13 AM
    Subject: [Winpcap-users] pcap_loop pointers

    I think that my question represents also other users.
    When using the function "pcap_loop"  the system uses the fallowing callback
    whenever a packet arrives -

          typedef void(* pcap_handler)(u_char *user, const struct pcap_pkthdr
    *pkt_header, const u_char *pkt_data)

    My questions-

    1. I saw that the pointers pkt_data and pkt_header differ from packet to
    Does that mean that the data on which they point occupies different area in


    2. How do I know if the data pointed by them is still valid in a certain

  Those pointers are valid *only* in the context of the pcap_handler callback. Packets are reused as soon as the pcap_handler callback returns.

  Have a nice day


    I. Lesher


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