[Winpcap-users] pcap_loop pointers

[Gianluca Varenni]

  ----- 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
  packet.
  Does that mean that the data on which they point occupies different area in
  memory?

Yes.

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

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
GV


  Regards

  I. Lesher




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