pcap_major_version, pcap_minor_version - get the version number of a savefile
#include <pcap/pcap.h>
int pcap_major_version(pcap_t *p);
int pcap_minor_version(pcap_t *p);
If p refers to a ``savefile'', pcap_major_version() returns the
  major number of the file format of the ``savefile'' and
  pcap_minor_version() returns the minor number of the file format of the
  ``savefile''. The version number is stored in the ``savefile''; note that the
  meaning of its values depends on the type of ``savefile'' (for example, pcap
  or pcapng).
If p refers to a live capture, the values returned by
    pcap_major_version() and pcap_minor_version() are not
    meaningful.